Nelson Vergel
Founder, ExcelMale.com
TESTOSTERONE DRUG INTERACTIONS
The interplay between medications and testosterone involves a complex network of biochemical interactions that can significantly affect a patient's health. Below is a detailed discussion of various medications and how they interact with testosterone. It is important to understand these interactions to optimize treatment outcomes and minimize adverse effects. As always, healthcare professionals should carefully consider these factors when prescribing medications to ensure the best possible patient care.
Definitions of Terms:
Abarelix: (Major) Concomitant use of androgens or estrogens with abarelix is relatively contraindicated, as both could counteract the therapeutic effect of abarelix.
Acarbose: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Alogliptin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Alogliptin; Metformin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Alogliptin; Pioglitazone: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Alpha-glucosidase Inhibitors: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Ambrisentan: (Moderate) Ambrisentan is a substrate for P-glycoprotein (P-gp). The inhibition of P-gp, by drugs such as testosterone, may lead to a decrease in the intestinal metabolism and an increase in the oral absorption of ambrisentan. If ambrisentan is coadministered with a P-gp inhibitor, patients should be monitored closely for adverse effects.
Aprepitant, Fosaprepitant: (Moderate) Use caution if systemic testosterone and aprepitant, fosaprepitant are used concurrently and monitor for an increase in testosterone-related adverse effects for several days after administration of a multi-day aprepitant regimen. Topical preparations of testosterone are not expected to have this interaction. Testosterone is a CYP3A4 substrate. Aprepitant, when administered as a 3-day oral regimen (125 mg/80 mg/80 mg), is a moderate CYP3A4 inhibitor and inducer and may increase plasma concentrations of testosterone. For example, a 5-day oral aprepitant regimen increased the AUC of another CYP3A4 substrate, midazolam (single dose), by 2.3-fold on day 1 and by 3.3-fold on day 5. After a 3-day oral aprepitant regimen, the AUC of midazolam (given on days 1, 4, 8, and 15) increased by 25% on day 4, and then decreased by 19% and 4% on days 8 and 15, respectively. As a single 125 mg or 40 mg oral dose, the inhibitory effect of aprepitant on CYP3A4 is weak, with the AUC of midazolam increased by 1.5-fold and 1.2-fold, respectively. After administration, fosaprepitant is rapidly converted to aprepitant and shares many of the same drug interactions. However, as a single 150 mg intravenous dose, fosaprepitant only weakly inhibits CYP3A4 for a duration of 2 days; there is no evidence of CYP3A4 induction. Fosaprepitant 150 mg IV as a single dose increased the AUC of midazolam (given on days 1 and 4) by approximately 1.8-fold on day 1; there was no effect on day 4. Less than a 2-fold increase in the midazolam AUC is not considered clinically important.
Atazanavir: (Minor) The plasma concentrations of testosterone may be significantly elevated when administered concurrently with atazanavir. Clinical monitoring for adverse effects, such as libido changes and other hormone-induced effects, is recommended during coadministration. Atazanavir is an inhibitor of CYP3A4. Testosterone is a CYP3A4 substrate.
Atazanavir; Cobicistat: (Minor) Plasma concentrations of testosterone may be significantly elevated when administered with cobicistat. Clinical monitoring for adverse effects, such as libido changes and other hormone-induced effects, is recommended during coadministration. Cobicistat is a CYP3A4 and P-glycoprotein (P-gp) inhibitor, while testosterone is a CYP3A4 and P-gp substrate. (Minor) The plasma concentrations of testosterone may be significantly elevated when administered concurrently with atazanavir. Clinical monitoring for adverse effects, such as libido changes and other hormone-induced effects, is recommended during coadministration. Atazanavir is an inhibitor of CYP3A4. Testosterone is a CYP3A4 substrate.
Boceprevir: (Moderate) Close clinical monitoring is advised when administering testosterone with boceprevir due to an increased potential for testosterone-related adverse events. If testosterone dose adjustments are made, re-adjust the dose upon completion of boceprevir treatment. Although this interaction has not been studied, predictions about the interaction can be made based on the metabolic pathway of testosterone. Testosterone is a substrate of the drug efflux transporter P-glycoprotein (PGP) and of the hepatic isoenzyme CYP3A4; boceprevir is an inhibitor of both the efflux protein and the isoenzyme. Coadministration may result in elevated testosterone plasma concentrations.
Cabozantinib: (Minor) Monitor for an increase in testosterone-related adverse reactions if coadministration of a systemic testosterone preparation with cabozantinib is necessary. Testosterone is a P-glycoprotein (P-gp) substrate. Cabozantinib is a P-gp inhibitor and has the potential to increase plasma concentrations of P-gp substrates; however, the clinical relevance of this finding is unknown. Interactions are not expected with topical testosterone preparations.
Canagliflozin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Canagliflozin; Metformin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Carvedilol: (Moderate) Altered concentrations of testosterone and/or carvedilol may occur during coadministration. Carvedilol and testosterone are both substrates and inhibitors of P-glycoprotein (P-gp). Use caution if concomitant use is necessary and monitor for increased side effects.
Cobicistat: (Minor) Plasma concentrations of testosterone may be significantly elevated when administered with cobicistat. Clinical monitoring for adverse effects, such as libido changes and other hormone-induced effects, is recommended during coadministration. Cobicistat is a CYP3A4 and P-glycoprotein (P-gp) inhibitor, while testosterone is a CYP3A4 and P-gp substrate.
Cobicistat; Elvitegravir; Emtricitabine; Tenofovir Alafenamide: (Minor) Plasma concentrations of testosterone may be significantly elevated when administered with cobicistat. Clinical monitoring for adverse effects, such as libido changes and other hormone-induced effects, is recommended during coadministration. Cobicistat is a CYP3A4 and P-glycoprotein (P-gp) inhibitor, while testosterone is a CYP3A4 and P-gp substrate.
Cobicistat; Elvitegravir; Emtricitabine; Tenofovir Disoproxil Fumarate: (Moderate) Caution is advised when administering tenofovir, PMPA, a P-glycoprotein (P-gp) substrate, concurrently with inhibitors of P-gp, such as testosterone. Coadministration may result in increased absorption of tenofovir. Monitor for tenofovir-associated adverse reactions. (Minor) Plasma concentrations of testosterone may be significantly elevated when administered with cobicistat. Clinical monitoring for adverse effects, such as libido changes and other hormone-induced effects, is recommended during coadministration. Cobicistat is a CYP3A4 and P-glycoprotein (P-gp) inhibitor, while testosterone is a CYP3A4 and P-gp substrate.
Cobimetinib: (Minor) If concurrent use of cobimetinib and testosterone is necessary, use caution and monitor for a possible increase in cobimetinib-related adverse effects. Cobimetinib is a P-glycoprotein (P-gp) substrate, and testosterone is a P-gp inhibitor; coadministration may result in increased cobimetinib exposure. However, coadministration of cobimetinib with another P-gp inhibitor, vemurafenib (960 mg twice daily), did not result in clinically relevant pharmacokinetic drug interactions. Topical preparations of testosterone are not expected to have this interaction.
Conivaptan: (Major) Avoid coadministration of conivaptan, a CYP3A4/P-glycoprotein (P-gp) inhibitor and testosterone, a CYP3A4/P-gp substrate. Concurrent use may result in elevated testosterone serum concentrations. According to the manufacturer, concomitant use of conivaptan, a strong CYP3A4 inhibitor, and CYP3A substrates, such as testosterone, should be avoided. Coadministration of conivaptan with other CYP3A substrates has resulted in increased mean AUC values (2 to 3 times). Theoretically, similar pharmacokinetic effects could be seen with testosterone. Treatment with testosterone may be initiated no sooner than 1 week after completion of conivaptan therapy.
Corticosteroids: (Moderate) Coadministration of corticosteroids and testosterone may increase the risk of edema, especially in patients with underlying cardiac or hepatic disease. Corticosteroids with greater mineralocorticoid activity, such as fludrocortisone, may be more likely to cause edema. Administer these drugs in combination with caution.
Cyclosporine: (Moderate) Androgens may increase concentrations of cyclosporine, potentially increasing the risk of nephrotoxicity. Until further data are available, close monitoring of cyclosporine serum concentrations is prudent during coadministration with androgens.
Dabigatran: (Moderate) Increased serum concentrations of dabigatran are possible when dabigatran, a P-glycoprotein (P-gp) substrate, is coadministered with testosterone, a P-gp inhibitor. Patients should be monitored for increased adverse effects of dabigatran. When dabigatran is administered for treatment or reduction in risk of recurrence of deep venous thrombosis (DVT) or pulmonary embolism (PE), or prophylaxis of DVT or PE following hip replacement surgery, avoid coadministration with P-gp inhibitors like testosterone in patients with CrCl less than 50 mL/minute. When dabigatran is used in patients with non-valvular atrial fibrillation and severe renal impairment (CrCl less than 30 mL/minute), avoid coadministration with testosterone, as serum concentrations of dabigatran are expected to be higher than when administered to patients with normal renal function. P-gp inhibition and renal impairment are the major independent factors that result in increased exposure to dabigatran.
Daclatasvir: (Minor) Systemic exposure of testosterone, a P-glycoprotein (P-gp) substrate, may be increased when administered concurrently with daclatasvir, a P-gp inhibitor. Taking these drugs together could increase or prolong the therapeutic effects of testosterone; monitor patients for potential adverse effects.
Dapagliflozin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Dapagliflozin; Metformin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Dapagliflozin; Saxagliptin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Darbepoetin Alfa: (Moderate) Androgens are known to stimulate erythropoiesis. Concurrent administration of androgens can increase the patient's response to darbepoetin alfa, reducing the amount required to treat anemia.
Darunavir: (Minor) The plasma concentrations of testosterone may be significantly elevated when administered concurrently with darunavir. Clinical monitoring for adverse effects, such as libido changes and other hormone-induced effects, is recommended during coadministration. Darunavir is an inhibitor of CYP3A4. Testosterone is a CYP3A4 substrate.
Darunavir; Cobicistat: (Minor) Plasma concentrations of testosterone may be significantly elevated when administered with cobicistat. Clinical monitoring for adverse effects, such as libido changes and other hormone-induced effects, is recommended during coadministration. Cobicistat is a CYP3A4 and P-glycoprotein (P-gp) inhibitor, while testosterone is a CYP3A4 and P-gp substrate. (Minor) The plasma concentrations of testosterone may be significantly elevated when administered concurrently with darunavir. Clinical monitoring for adverse effects, such as libido changes and other hormone-induced effects, is recommended during coadministration. Darunavir is an inhibitor of CYP3A4. Testosterone is a CYP3A4 substrate.
Darunavir; Cobicistat; Emtricitabine; Tenofovir alafenamide: (Minor) Plasma concentrations of testosterone may be significantly elevated when administered with cobicistat. Clinical monitoring for adverse effects, such as libido changes and other hormone-induced effects, is recommended during coadministration. Cobicistat is a CYP3A4 and P-glycoprotein (P-gp) inhibitor, while testosterone is a CYP3A4 and P-gp substrate. (Minor) The plasma concentrations of testosterone may be significantly elevated when administered concurrently with darunavir. Clinical monitoring for adverse effects, such as libido changes and other hormone-induced effects, is recommended during coadministration. Darunavir is an inhibitor of CYP3A4. Testosterone is a CYP3A4 substrate.
Dasabuvir; Ombitasvir; Paritaprevir; Ritonavir: (Moderate) Concurrent administration of testosterone with dasabuvir; ombitasvir; paritaprevir; ritonavir may result in elevated plasma concentrations of testosterone, dasabuvir, ombitasvir, paritaprevir, and ritonavir. Testosterone is a substrate of the hepatic isoenzyme CYP3A4 and the drug transporter P-glycoprotein (P-gp). Ritonavir is a potent CYP3A4 inhibitor; it also inhibits P-gp. In addition, testosterone inhibits the drug transporter P-glycoprotein (P-gp); dasabuvir, ombitasvir, paritaprevir and ritonavir are all substrates of P-gp. Caution and close monitoring are advised if these drugs are administered together. (Moderate) Concurrent administration of testosterone with dasabuvir; ombitasvir; paritaprevir; ritonavir or ombitasvir; paritaprevir; ritonavir may result in elevated plasma concentrations of testosterone, dasabuvir, ombitasvir, paritaprevir, and ritonavir. Testosterone is a substrate of the hepatic isoenzyme CYP3A4 and the drug transporter P-glycoprotein (P-gp). Ritonavir is a potent CYP3A4 inhibitor; it also inhibits P-gp. Paritaprevir also inhibits P-gp. In addition, testosterone inhibits the drug transporter P-glycoprotein (P-gp); dasabuvir, ombitasvir, paritaprevir and ritonavir are all substrates of P-gp. Caution and close monitoring are advised if these drugs are administered together. (Moderate) Concurrent administration of testosterone with ritonavir may result in elevated plasma concentrations of testosterone and ritonavir. Testosterone is a substrate of the hepatic isoenzyme CYP3A4 and the drug transporter P-glycoprotein (P-gp). Ritonavir is a CYP3A4 and P-gp inhibitor. In addition, testosterone inhibits P-gp; ritonavir is a substrate of P-gp. Caution and close monitoring are advised if these drugs are administered together.
Degarelix: (Major) Concomitant use of androgens with degarelix is relatively contraindicated, as androgens could counteract the therapeutic effect of degarelix.
Dipeptidyl Peptidase-4 Inhibitors: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Doravirine; Lamivudine; Tenofovir disoproxil fumarate: (Moderate) Caution is advised when administering tenofovir, PMPA, a P-glycoprotein (P-gp) substrate, concurrently with inhibitors of P-gp, such as testosterone. Coadministration may result in increased absorption of tenofovir. Monitor for tenofovir-associated adverse reactions.
Dronedarone: (Moderate) Dronedarone is metabolized by and is an inhibitor of CYP3A; dronedarone also inhibits P-gp. Testosterone is a substrate for CYP3A4 and P-gp. The concomitant administration of dronedarone with CYP3A4 and P-gp substrates may result in increased exposure of the substrate and should, therefore, be undertaken with caution.
Edoxaban: (Moderate) Coadministration of edoxaban and testosterone may result in increased concentrations of edoxaban. Edoxaban is a P-glycoprotein (P-gp) substrate and testosterone is a P-gp inhibitor. Increased concentrations of edoxaban may occur during concomitant use of testosterone; monitor for increased adverse effects of edoxaban. Dosage reduction may be considered for patients being treated for deep venous thrombosis (DVT) or pulmonary embolism.
Efavirenz; Emtricitabine; Tenofovir: (Moderate) Caution is advised when administering tenofovir, PMPA, a P-glycoprotein (P-gp) substrate, concurrently with inhibitors of P-gp, such as testosterone. Coadministration may result in increased absorption of tenofovir. Monitor for tenofovir-associated adverse reactions.
Efavirenz; Lamivudine; Tenofovir Disoproxil Fumarate: (Moderate) Caution is advised when administering tenofovir, PMPA, a P-glycoprotein (P-gp) substrate, concurrently with inhibitors of P-gp, such as testosterone. Coadministration may result in increased absorption of tenofovir. Monitor for tenofovir-associated adverse reactions.
Elbasvir; Grazoprevir: (Minor) Administering testosterone with grazoprevir may result in elevated testosterone plasma concentrations. Testosterone is a substrate of CYP3A; grazoprevir is a weak CYP3A inhibitor. If these drugs are used together, closely monitor for signs of adverse events.
Eliglustat: (Moderate) Coadministration of testosterone and eliglustat may result in increased plasma concentrations of testosterone. Monitor patients closely for testosterone-related adverse effects. Testosterone is a P-glycoprotein (P-gp) substrate; eliglustat is a P-gp inhibitor.
Empagliflozin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Empagliflozin; Linagliptin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Empagliflozin; Metformin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Emtricitabine; Rilpivirine; Tenofovir disoproxil fumarate: (Moderate) Caution is advised when administering tenofovir, PMPA, a P-glycoprotein (P-gp) substrate, concurrently with inhibitors of P-gp, such as testosterone. Coadministration may result in increased absorption of tenofovir. Monitor for tenofovir-associated adverse reactions.
Emtricitabine; Tenofovir disoproxil fumarate: (Moderate) Caution is advised when administering tenofovir, PMPA, a P-glycoprotein (P-gp) substrate, concurrently with inhibitors of P-gp, such as testosterone. Coadministration may result in increased absorption of tenofovir. Monitor for tenofovir-associated adverse reactions.
Epoetin Alfa: (Moderate) Androgens are known to stimulate erythropoiesis. Concurrent administration of androgens can increase the patient's response to epoetin alfa, reducing the amount required to treat anemia. Because adverse reactions have been associated with an abrupt increase in blood viscosity, this drug combination should be avoided, if possible. Further evaluation of this combination needs to be made.
Ertugliflozin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Ertugliflozin; Metformin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Ertugliflozin; Sitagliptin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Etoposide, VP-16: (Major) Monitor for an increased incidence of etoposide-related adverse effects if used concomitantly with testosterone. Testosterone is an inhibitor of P-glycoprotein (P-gp) and etoposide, VP-16 is a P-gp substrate. Coadministration may increase etoposide concentrations.
Everolimus: (Major) Everolimus is an inhibitor and substrate of CYP3A4 and Pgp. Coadministration with inhibitors of Pgp, such as testosterone, is not recommended. Patients may experience an increase in systemic exposure to everolimus if these drugs are coadministered. In addition, testosterone is a substrate of CYP3A4. The effect of everolimus on testosterone pharmacokinetics has not been established; however, pharmacokinetic studies showed no significant impact of the coadministration of everolimus with the CYP3A4 and Pgp substrate atorvastatin.
Fluconazole: (Minor) Testosterone concentrations may increase during fluconazole administration. Fluconazole is an inhibitor of CYP3A4, the hepatic microsomal isoenzyme responsible for metabolism of testosterone. The clinical significance of this interaction is unclear at this time.
Fosamprenavir: (Moderate) Concomitant use of testosterone and fosamprenavir may result in elevated fosamprenavir and altered testosterone plasma concentrations. Testosterone is a substrate of the hepatic isoenzyme CYP3A4 and a substrate/inhibitor of the drug transporter P-glycoprotein (P-gp). Amprenavir, the active metabolite of fosamprenavir, is substrate/inducer of P-gp and a potent inhibitor/moderate inducer of CYP3A4.
Glipizide; Metformin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Glyburide; Metformin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Goserelin: (Major) Goserelin inhibits steroidogenesis. Concomitant use of androgens, like fluoxymesterone, with goserelin is relatively contraindicated and would defeat the purpose of goserelin therapy.
Histrelin: (Major) Avoid concurrent use of androgens with gonadotropin releasing hormone (GnRH) agonists such as histrelin. Histrelin inhibits steroidogenesis; concomitant use with androgens may counteract this therapeutic effect.
Hydrochlorothiazide, HCTZ; Propranolol: (Moderate) Testosterone cypionate has been shown to increase the clearance of propranolol in one study. Monitor patients taking testosterone and propranolol together for decreased therapeutic efficacy of propranolol.
Idelalisib: (Major) Avoid concomitant use of idelalisib, a strong CYP3A inhibitor, with testosterone, a CYP3A substrate, as testosterone toxicities may be significantly increased. The AUC of a sensitive CYP3A substrate was increased 5.4-fold when coadministered with idelalisib.
Incretin Mimetics: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Insulins: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Isavuconazonium: (Moderate) The plasma concentrations of testosterone may be elevated when administered concurrently with isavuconazonium. Clinical monitoring for adverse effects, such as libido changes and other hormone-induced effects, is recommended during coadministration. Testosterone is a substrate of the hepatic isoenzyme CYP3A4 and drug transporter P-glycoprotein (P-gp); isavuconazole, the active moiety of isavuconazonium, is an inhibitor of CYP3A4 and P-gp.
Ixabepilone: (Minor) Testosterone is an inhibitor of and substrate for P-glycoprotein (Pgp). Ixabepilone is a mild inhibitor of and substrate for Pgp. Concomitant use of these agents may cause an increase in ixabepilone concentrations and/or an increase in testosterone concentrations. Caution is recommended if ixabepilone is coadministered with a Pgp inhibitor.
Lamivudine; Tenofovir Disoproxil Fumarate: (Moderate) Caution is advised when administering tenofovir, PMPA, a P-glycoprotein (P-gp) substrate, concurrently with inhibitors of P-gp, such as testosterone. Coadministration may result in increased absorption of tenofovir. Monitor for tenofovir-associated adverse reactions.
Leuprolide: (Major) Leuprolide inhibits steroidogenesis. While no drug interactions have been reported with leuprolide, therapy with androgens would be relatively contraindicated and would counteract the therapeutic effect of leuprolide.
Leuprolide; Norethindrone: (Major) Leuprolide inhibits steroidogenesis. While no drug interactions have been reported with leuprolide, therapy with androgens would be relatively contraindicated and would counteract the therapeutic effect of leuprolide.
Linagliptin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Linagliptin; Metformin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Loperamide: (Moderate) The plasma concentration of loperamide, a P-glycoprotein (P-gp) substrate, may be increased when administered concurrently with testosterone, a P-gp inhibitor. If these drugs are used together, monitor for loperamide-associated adverse reactions, such as CNS effects and cardiac toxicities (i.e., syncope, ventricular tachycardia, QT prolongation, torsade de pointes, cardiac arrest).
Loperamide; Simethicone: (Moderate) The plasma concentration of loperamide, a P-glycoprotein (P-gp) substrate, may be increased when administered concurrently with testosterone, a P-gp inhibitor. If these drugs are used together, monitor for loperamide-associated adverse reactions, such as CNS effects and cardiac toxicities (i.e., syncope, ventricular tachycardia, QT prolongation, torsade de pointes, cardiac arrest).
Lopinavir; Ritonavir: (Moderate) Concurrent administration of testosterone with lopinavir; ritonavir may result in elevated plasma concentrations of testosterone and ritonavir. Testosterone is a substrate of the hepatic isoenzyme CYP3A4 and the drug transporter P-glycoprotein (P-gp). Ritonavir is a CYP3A4 and P-gp inhibitor, while lopinavir also inhibits P-gp. In addition, testosterone inhibits P-gp; ritonavir is a substrate of P-gp. Caution and close monitoring are advised if these drugs are administered together. (Moderate) Concurrent administration of testosterone with ritonavir may result in elevated plasma concentrations of testosterone and ritonavir. Testosterone is a substrate of the hepatic isoenzyme CYP3A4 and the drug transporter P-glycoprotein (P-gp). Ritonavir is a CYP3A4 and P-gp inhibitor. In addition, testosterone inhibits P-gp; ritonavir is a substrate of P-gp. Caution and close monitoring are advised if these drugs are administered together.
Lumacaftor; Ivacaftor: (Minor) Lumacaftor; ivacaftor may alter the exposure of testosterone. Testosterone is a substrate of CYP3A and the P-glycoprotein (P-gp) drug transporter. Lumacaftor is a strong CYP3A inducer; in vitro data suggest lumacaftor; ivacaftor may also induce and/or inhibit P-gp. Although induction of testosterone metabolism through the CYP3A pathway may lead to decreased drug efficacy, the net effect of lumacaftor; ivacaftor on P-gp transport is not clear.
Maraviroc: (Moderate) Use caution and careful monitoring with the coadministration of maraviroc and testosterone as increased maraviroc concentrations may occur. Maraviroc is a substrate of P-glycoprotein (P-gp); testosterone is an inhibitor of P-gp. The effects of P-gp on the concentrations of maraviroc are unknown, although an increase in concentrations and thus, toxicity, are possible.
Meglitinides: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Metformin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Metformin; Pioglitazone: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Metformin; Repaglinide: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Metformin; Rosiglitazone: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Metformin; Saxagliptin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Metformin; Sitagliptin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Methoxy polyethylene glycol-epoetin beta: (Moderate) Androgens are known to stimulate erythropoiesis. Despite the fact that endogenous generation of erythropoietin is depressed in patients with chronic renal failure, other tissues besides the kidney can synthesize erythropoietin, albeit in small amounts. Concurrent administration of androgens can increase the patient's response to MPG-epoetin beta, reducing the amount required to treat anemia. Because adverse reactions have been associated with an abrupt increase in blood viscosity, this drug combination should be avoided, if possible. Further evaluation of this combination needs to be made.
Miglitol: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Mitotane: (Moderate) Use caution if mitotane and testosterone are used concomitantly, and monitor for decreased efficacy of testosterone and a possible change in dosage requirements. Mitotane is a strong CYP3A4 inducer and testosterone is a CYP3A4 substrate; coadministration may result in decreased plasma concentrations of testosterone. Topical preparations of testosterone are not expected to have this interaction.
Nafarelin: (Major) Gonadotropin releasing hormone (GnRH) agonists (i.e.,nafarelin) inhibit steroidogenesis, therefore the concomitant use of these agents with androgens may counteract this therapeutic effect. Avoid concurrent use of androgens with GnRH agonists.
Nanoparticle Albumin-Bound Paclitaxel: (Minor) Paclitaxel is metabolized by hepatic cytochrome P450 (CYP) isoenzymes 2C8 and 3A4. Testosterone inhibited the formation of paclitaxel metabolites in vitro. Combining the drugs in clinical practice may require close monitoring to ensure proper therapeutic responses.
Ombitasvir; Paritaprevir; Ritonavir: (Moderate) Concurrent administration of testosterone with dasabuvir; ombitasvir; paritaprevir; ritonavir may result in elevated plasma concentrations of testosterone, dasabuvir, ombitasvir, paritaprevir, and ritonavir. Testosterone is a substrate of the hepatic isoenzyme CYP3A4 and the drug transporter P-glycoprotein (P-gp). Ritonavir is a potent CYP3A4 inhibitor; it also inhibits P-gp. In addition, testosterone inhibits the drug transporter P-glycoprotein (P-gp); dasabuvir, ombitasvir, paritaprevir and ritonavir are all substrates of P-gp. Caution and close monitoring are advised if these drugs are administered together. (Moderate) Concurrent administration of testosterone with dasabuvir; ombitasvir; paritaprevir; ritonavir or ombitasvir; paritaprevir; ritonavir may result in elevated plasma concentrations of testosterone, dasabuvir, ombitasvir, paritaprevir, and ritonavir. Testosterone is a substrate of the hepatic isoenzyme CYP3A4 and the drug transporter P-glycoprotein (P-gp). Ritonavir is a potent CYP3A4 inhibitor
Oritavancin:
(Minor) Testosterone is metabolized by CYP3A4; oritavancin is a weak CYP3A4 inducer. Plasma concentrations and efficacy of testosterone may be reduced if these drugs are administered concurrently.
Oxymetazoline:
(Moderate) The drug interaction potential between intranasal testosterone (e.g., Natesto) and other intranasally administered drugs other than sympathomimetic decongestants is unknown. Therefore, concomitant use of intranasal testosterone with intranasal drugs other than sympathomimetic decongestants (e.g., oxymetazoline) is not recommended. Eighteen males with seasonal allergic rhinitis were treated with intranasal testosterone and randomized to receive oxymetazoline (30 minutes prior to intranasal testosterone) or no treatment. In general, serum total testosterone concentrations were decreased by 21-24% in males with symptomatic allergic rhinitis, due to the underlying condition. A mean decrease in AUC and Cmax (2.6% and 3.6%, respectively) for total testosterone was observed in males with symptomatic seasonal rhinitis when treated with oxymetazoline compared to untreated patients. Concomitant use of oxymetazoline does not impact the absorption of testosterone.
Pazopanib:
(Moderate) Pazopanib is a weak inhibitor of CYP3A4 and a substrate for P-glycoprotein (Pgp). Testosterone is a substrate for CYP3A4 and an inhibitor of Pgp. Concurrent administration of testosterone and pazopanib may result in increased pazopanib concentrations and/or increased testosterone concentrations. Use caution when concurrent administration of testosterone and pazopanib is necessary.
Posaconazole:
(Major) Posaconazole and testosterone should be coadministered with caution due to an increased potential for adverse events. This complex interaction may cause alterations in the plasma concentrations of both posaconazole and testosterone, ultimately resulting in an increased risk of adverse events. Posaconazole is a potent inhibitor of CYP3A4, an isoenzyme partially responsible for the metabolism of testosterone. Further, both testosterone and posaconazole are inhibitors and substrates of the drug efflux protein, P-glycoprotein, which when administered together may increase the absorption or decrease the clearance of the other drug.
Pramlintide:
(Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Propranolol:
(Moderate) Testosterone cypionate has been shown to increase the clearance of propranolol in one study. Monitor patients taking testosterone and propranolol together for decreased therapeutic efficacy of propranolol.
Ranolazine:
(Moderate) Testosterone is an inhibitor of P-glycoprotein transport. Ranolazine is a substrate of P-glycoprotein, and inhibitors of P-glycoprotein may increase the absorption of ranolazine. In addition, ranolazine inhibits CYP3A and may increase plasma concentrations of drugs that are primarily metabolized by CYP3A4 such as testosterone.
Rifaximin:
(Moderate) Although the clinical significance of this interaction is unknown, concurrent use of rifaximin, a P-glycoprotein (P-gp) substrate, and testosterone, a P-gp inhibitor, may substantially increase the systemic exposure to rifaximin; caution is advised if these drugs must be administered together. During one in vitro study, coadministration with cyclosporine, a potent P-gp inhibitor, resulted in an 83-fold and 124-fold increase in the mean Cmax and AUC of rifaximin, respectively. In patients with hepatic impairment, the effects of reduced metabolism and P-gp inhibition may further increase exposure to rifaximin.
Ritonavir:
(Moderate) Concurrent administration of testosterone with ritonavir may result in elevated plasma concentrations of testosterone and ritonavir. Testosterone is a substrate of the hepatic isoenzyme CYP3A4 and the drug transporter P-glycoprotein (P-gp). Ritonavir is a CYP3A4 and P-gp inhibitor. In addition, testosterone inhibits P-gp; ritonavir is a substrate of P-gp. Caution and close monitoring are advised if these drugs are administered together.
Rivaroxaban:
(Minor) Coadministration of rivaroxaban and testosterone may result in increases in rivaroxaban exposure and may increase bleeding risk. Testosterone is an inhibitor of P-gp, and rivaroxaban is a substrate of P-gp. If these drugs are administered concurrently, monitor the patient for signs and symptoms of bleeding.
Romidepsin:
(Moderate) Romidepsin is a substrate for P-glycoprotein. Testosterone is an inhibitor of P-gp. Concurrent administration of romidepsin with an inhibitor of P-gp may cause an increase in systemic romidepsin concentrations. Use caution when concomitant administration of these agents is necessary.
Sapropterin:
(Minor) Caution is advised with the concomitant use of sapropterin and testosterone as coadministration may result in increased systemic exposure of testosterone. Testosterone is a substrate for the drug transporter P-glycoprotein (P-gp); in vitro data show that sapropterin may inhibit P-gp. If these drugs are used together, closely monitor for increased side effects of testosterone.
Saw Palmetto, Serenoa repens:
(Major) Drug interactions with Saw palmetto, Serenoa repens have not been specifically studied or reported. Saw palmetto extracts appear to have antiandrogenic effects. The antiandrogenic effects of Saw palmetto, Serenoa repens would be expected to antagonize the actions of androgens; it would seem illogical for patients taking androgens to use this herbal supplement.
Saxagliptin:
(Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
SGLT2 Inhibitors:
(Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Simvastatin; Sitagliptin:
(Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Sitagliptin:
(Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Sofosbuvir; Velpatasvir:
(Moderate) Use caution when administering velpatasvir with testosterone. Taking these medications together may increase the plasma concentrations of both drugs, potentially resulting in adverse events. Both drugs are substrates and inhibitors of the drug transporter P-glycoprotein (P-gp).
Sofosbuvir; Velpatasvir; Voxilaprevir:
(Moderate) Plasma concentrations of testosterone, a P-glycoprotein (P-gp) substrate, may be increased when administered concurrently with voxilaprevir, a P-gp inhibitor. Monitor patients for increased side effects if these drugs are administered concurrently. (Moderate) Use caution when administering velpatasvir with testosterone. Taking these medications together may increase the plasma concentrations of both drugs, potentially resulting in adverse events. Both drugs are substrates and inhibitors of the drug transporter P-glycoprotein (P-gp).
Somatropin, rh-GH:
(Moderate) Somatropin can induce (i.e., increase) the activity of cytochrome-mediated metabolism of antipyrine clearance in man. Thus, this predicts that somatropin may affect other drugs metabolized via this pathway, like testosterone.
Soy Isoflavones:
(Moderate) Theoretically, the soy isoflavones may counteract the activity of the androgens.
St. John's Wort, Hypericum perforatum:
(Moderate) St. John's Wort appears to induce several isoenzymes of the hepatic cytochrome P450 enzyme system, including CYP3A4, CYP1A2, and potentially CYP2C9. Co-administration of St. John's Wort could decrease the efficacy of some medications metabolized by these enzymes, including testosterone.
Sulfonylureas:
(Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Telaprevir:
(Moderate) Close clinical monitoring is advised when administering testosterone with telaprevir due to an increased potential for testosterone-related adverse events. Coadministration may result in elevated testosterone plasma concentrations. If testosterone dose adjustments are made, re-adjust the dose upon completion of telaprevir treatment. Although this interaction has not been studied, predictions about the interaction can be made based on the metabolic pathway of testosterone. Testosterone is a substrate of the drug efflux transporter P-glycoprotein (P-gp) and of the hepatic isoenzyme CYP3A4; telaprevir is an inhibitor of both the efflux protein and the isoenzyme.
Telotristat Ethyl:
(Moderate) Use caution if coadministration of telotristat ethyl and testosterone is necessary, as the systemic exposure of testosterone may be decreased resulting in reduced efficacy; exposure to telotristat ethyl may also be increased. If these drugs are used together, monitor patients for suboptimal efficacy of testosterone as well as an increase in adverse reactions related to telotristat ethyl. Consider increasing the dose of testosterone if necessary. Testosterone is a CYP3A4 substrate. The mean Cmax and AUC of another sensitive CYP3A4 substrate was decreased by 25% and 48%, respectively, when coadministered with telotristat ethyl; the mechanism of this interaction appears to be that telotristat ethyl increases the glucuronidation of the CYP3A4 substrate. Additionally, the active metabolite of telotristat ethyl, telotristat, is a substrate of P-glycoprotein (P-gp) and testosterone is a P-gp inhibitor. Exposure to telotristat ethyl may increase.
Tenofovir Alafenamide:
(Minor) Caution is advised when administering tenofovir alafenamide concurrently with testosterone, as coadministration may result in elevated tenofovir alafenamide plasma concentrations. Inhibitors of the drug transporter P-glycoprotein (P-gp), such as testosterone, may increase absorption of tenofovir alafenamide, a P-gp substrate. If these medications are administered together, monitor for tenofovir-associated adverse reactions. Of note, when tenofovir alafenamide is administered as part of a cobicistat-containing product, its availability is increased by cobicistat and a further increase of tenofovir alafenamide concentrations is not expected upon coadministration of an additional P-gp inhibitor.
Tenofovir, PMPA:
(Moderate) Caution is advised when administering tenofovir, PMPA, a P-glycoprotein (P-gp) substrate, concurrently with inhibitors of P-gp, such as testosterone. Coadministration may result in increased absorption of tenofovir. Monitor for tenofovir-associated adverse reactions.
Thiazolidinediones:
(Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Ticagrelor:
(Moderate) Coadministration of ticagrelor and testosterone may result in increased exposure to ticagrelor which may increase the bleeding risk. Ticagrelor is a P-glycoprotein (P-gp) substrate and testosterone is a P-gp inhibitor. Based on drug information data with cyclosporine, no dose adjustment is recommended by the manufacturer of ticagrelor. Use combination with caution and monitor for evidence of bleeding.
Tolvaptan:
(Major) Tolvaptan is a substrate for P-gp. Testosterone is an inhibitor of P-gp. Coadministration may result in increased exposure of tolvaptan; a reduction in the dose of tolvaptan may be required.
Triptorelin:
(Major) Gonadotropin releasing hormone (GnRH) agonists (i.e.,triptorelin) inhibit steroidogenesis, therefore the concomitant use of these agents with androgens may counteract this therapeutic effect. Avoid concurrent use of androgens with GnRH agonists.
Vandetanib: (Moderate) Use caution if coadministration of vandetanib with testosterone is necessary, due to a possible increase in testosterone-related adverse reactions. Testosterone is a partial substrate of P-glycoprotein (P-gp). Coadministration with vandetanib increased the Cmax and AUC of another P-gp substrate by 29% and 23%, respectively. This interaction is not expected for topical preparations of testosterone.
Vemurafenib: (Moderate) Concomitant use of vemurafenib and testosterone may result in altered concentrations of testosterone and increased concentrations of vemurafenib. Vemurafenib is a substrate/inducer of CYP3A4 and a substrate/inhibitor of P-glycoprotein (PGP).Testosterone is a substrate of CYP3A4 and a substrate/inhibitor of PGP. Use caution and monitor patients for toxicity and efficacy.
Vinblastine: (Minor) Testosterone is an inhibitor of the efflux transporter P-glycoprotein. Vinblastine is a P-glycoprotein substrate. Increased concentrations of vinblastine are likely if it is coadministered with testosterone; exercise caution.
Vincristine Liposomal: (Major) Testosterone inhibits P-glycoprotein (P-gp), and vincristine is a P-gp substrate. Coadministration could increase exposure to vincristine; monitor patients for increased side effects if these drugs are given together.
Vincristine: (Major) Testosterone inhibits P-glycoprotein (P-gp), and vincristine is a P-gp substrate. Coadministration could increase exposure to vincristine; monitor patients for increased side effects if these drugs are given together.
Voriconazole: (Minor) Limited data suggest that testosterone concentrations increase during fluconazole administration. Although data are not available, a similar reaction may occur with voriconazole. Also, voriconazole is an inhibitor of CYP3A4, the hepatic microsomal isoenzyme responsible for metabolism of testosterone.
Warfarin: (Moderate) Testosterone can increase the anticoagulant action of warfarin. Serious bleeding has been reported in some patients with this drug-drug interaction. Although the mechanism is unclear, testosterone may reduce procoagulant factors. Reduction of warfarin dosage may be necessary if testosterone therapy is coadministered. More frequent monitoring of INR and prothrombin time in patients taking such oral anticoagulants is recommended, especially at the initiation and termination of androgen therapy. It is unclear if testosterone can augment the anticoagulant response to heparin therapy or if testosterone alters the effect of other non-coumarin oral anticoagulants in a similar manner.
Zonisamide: (Minor) Zonisamide is a weak inhibitor of P-glycoprotein (P-gp), and testosterone is a substrate of P-gp. There is theoretical potential for zonisamide to affect the pharmacokinetics of drugs that are P-gp substrates. Use caution when starting or stopping zonisamide or changing the zonisamide dosage in patients also receiving drugs which are P-gp substrates.
Reference: Depo-Testosterone (testosterone cypionate) dose, indications, adverse effects, interactions... from PDR.net
The interplay between medications and testosterone involves a complex network of biochemical interactions that can significantly affect a patient's health. Below is a detailed discussion of various medications and how they interact with testosterone. It is important to understand these interactions to optimize treatment outcomes and minimize adverse effects. As always, healthcare professionals should carefully consider these factors when prescribing medications to ensure the best possible patient care.
Definitions of Terms:
- P-glycoprotein (P-gp): P-glycoprotein is a type of efflux transporter. It's a protein that pumps various substances out of cells. In the context of drug interactions, P-gp can affect the absorption, distribution, and elimination of many drugs, including testosterone. It's known for its role in contributing to multidrug resistance in cancer cells.
- CYP3A4: This is a member of the cytochrome P450 family of enzymes. Cytochrome P450 enzymes are responsible for the metabolism of many drugs in the liver. CYP3A4, in particular, metabolizes a wide variety of drugs and is known for its role in drug-drug interactions. When a medication is a substrate of CYP3A4, it means that CYP3A4 enzymes metabolize it. If a drug is an inducer or inhibitor of this enzyme, it can increase or decrease the metabolism of other drugs that are substrates of CYP3A4.
- Substrate: In pharmacology, a substrate is a substance that is metabolized by an enzyme. When the content refers to a drug as a "substrate" of an enzyme like P-gp or CYP3A4, it means that the drug is acted upon and metabolized by that enzyme.
- Inducer: An inducer is a substance that increases the activity of an enzyme. In the context of drug metabolism, when a drug is an inducer of an enzyme like CYP3A4, it increases the metabolism of all the substrates of that enzyme, often leading to decreased effectiveness of the substrates.
- Inhibitor: An inhibitor is a substance that decreases the activity of an enzyme. A drug that acts as an inhibitor of an enzyme will decrease the metabolism of substrates for that enzyme. This can lead to increased concentrations of the substrates, potentially leading to an increased risk of side effects or toxicity.
- Cmax: This term refers to the maximum serum concentration that a drug achieves in a specified compartment or measurement in the body after the drug has been administered and prior to the administration of a second dose.
- AUC (Area Under the Curve): This is a measure of the total exposure to the drug. It represents the integral of the concentration-time curve (usually blood or plasma concentration) from the time of administration to the time of the last measurable concentration.
Abarelix: (Major) Concomitant use of androgens or estrogens with abarelix is relatively contraindicated, as both could counteract the therapeutic effect of abarelix.
Acarbose: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Alogliptin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Alogliptin; Metformin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Alogliptin; Pioglitazone: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Alpha-glucosidase Inhibitors: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Ambrisentan: (Moderate) Ambrisentan is a substrate for P-glycoprotein (P-gp). The inhibition of P-gp, by drugs such as testosterone, may lead to a decrease in the intestinal metabolism and an increase in the oral absorption of ambrisentan. If ambrisentan is coadministered with a P-gp inhibitor, patients should be monitored closely for adverse effects.
Aprepitant, Fosaprepitant: (Moderate) Use caution if systemic testosterone and aprepitant, fosaprepitant are used concurrently and monitor for an increase in testosterone-related adverse effects for several days after administration of a multi-day aprepitant regimen. Topical preparations of testosterone are not expected to have this interaction. Testosterone is a CYP3A4 substrate. Aprepitant, when administered as a 3-day oral regimen (125 mg/80 mg/80 mg), is a moderate CYP3A4 inhibitor and inducer and may increase plasma concentrations of testosterone. For example, a 5-day oral aprepitant regimen increased the AUC of another CYP3A4 substrate, midazolam (single dose), by 2.3-fold on day 1 and by 3.3-fold on day 5. After a 3-day oral aprepitant regimen, the AUC of midazolam (given on days 1, 4, 8, and 15) increased by 25% on day 4, and then decreased by 19% and 4% on days 8 and 15, respectively. As a single 125 mg or 40 mg oral dose, the inhibitory effect of aprepitant on CYP3A4 is weak, with the AUC of midazolam increased by 1.5-fold and 1.2-fold, respectively. After administration, fosaprepitant is rapidly converted to aprepitant and shares many of the same drug interactions. However, as a single 150 mg intravenous dose, fosaprepitant only weakly inhibits CYP3A4 for a duration of 2 days; there is no evidence of CYP3A4 induction. Fosaprepitant 150 mg IV as a single dose increased the AUC of midazolam (given on days 1 and 4) by approximately 1.8-fold on day 1; there was no effect on day 4. Less than a 2-fold increase in the midazolam AUC is not considered clinically important.
Atazanavir: (Minor) The plasma concentrations of testosterone may be significantly elevated when administered concurrently with atazanavir. Clinical monitoring for adverse effects, such as libido changes and other hormone-induced effects, is recommended during coadministration. Atazanavir is an inhibitor of CYP3A4. Testosterone is a CYP3A4 substrate.
Atazanavir; Cobicistat: (Minor) Plasma concentrations of testosterone may be significantly elevated when administered with cobicistat. Clinical monitoring for adverse effects, such as libido changes and other hormone-induced effects, is recommended during coadministration. Cobicistat is a CYP3A4 and P-glycoprotein (P-gp) inhibitor, while testosterone is a CYP3A4 and P-gp substrate. (Minor) The plasma concentrations of testosterone may be significantly elevated when administered concurrently with atazanavir. Clinical monitoring for adverse effects, such as libido changes and other hormone-induced effects, is recommended during coadministration. Atazanavir is an inhibitor of CYP3A4. Testosterone is a CYP3A4 substrate.
Boceprevir: (Moderate) Close clinical monitoring is advised when administering testosterone with boceprevir due to an increased potential for testosterone-related adverse events. If testosterone dose adjustments are made, re-adjust the dose upon completion of boceprevir treatment. Although this interaction has not been studied, predictions about the interaction can be made based on the metabolic pathway of testosterone. Testosterone is a substrate of the drug efflux transporter P-glycoprotein (PGP) and of the hepatic isoenzyme CYP3A4; boceprevir is an inhibitor of both the efflux protein and the isoenzyme. Coadministration may result in elevated testosterone plasma concentrations.
Cabozantinib: (Minor) Monitor for an increase in testosterone-related adverse reactions if coadministration of a systemic testosterone preparation with cabozantinib is necessary. Testosterone is a P-glycoprotein (P-gp) substrate. Cabozantinib is a P-gp inhibitor and has the potential to increase plasma concentrations of P-gp substrates; however, the clinical relevance of this finding is unknown. Interactions are not expected with topical testosterone preparations.
Canagliflozin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Canagliflozin; Metformin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Carvedilol: (Moderate) Altered concentrations of testosterone and/or carvedilol may occur during coadministration. Carvedilol and testosterone are both substrates and inhibitors of P-glycoprotein (P-gp). Use caution if concomitant use is necessary and monitor for increased side effects.
Cobicistat: (Minor) Plasma concentrations of testosterone may be significantly elevated when administered with cobicistat. Clinical monitoring for adverse effects, such as libido changes and other hormone-induced effects, is recommended during coadministration. Cobicistat is a CYP3A4 and P-glycoprotein (P-gp) inhibitor, while testosterone is a CYP3A4 and P-gp substrate.
Cobicistat; Elvitegravir; Emtricitabine; Tenofovir Alafenamide: (Minor) Plasma concentrations of testosterone may be significantly elevated when administered with cobicistat. Clinical monitoring for adverse effects, such as libido changes and other hormone-induced effects, is recommended during coadministration. Cobicistat is a CYP3A4 and P-glycoprotein (P-gp) inhibitor, while testosterone is a CYP3A4 and P-gp substrate.
Cobicistat; Elvitegravir; Emtricitabine; Tenofovir Disoproxil Fumarate: (Moderate) Caution is advised when administering tenofovir, PMPA, a P-glycoprotein (P-gp) substrate, concurrently with inhibitors of P-gp, such as testosterone. Coadministration may result in increased absorption of tenofovir. Monitor for tenofovir-associated adverse reactions. (Minor) Plasma concentrations of testosterone may be significantly elevated when administered with cobicistat. Clinical monitoring for adverse effects, such as libido changes and other hormone-induced effects, is recommended during coadministration. Cobicistat is a CYP3A4 and P-glycoprotein (P-gp) inhibitor, while testosterone is a CYP3A4 and P-gp substrate.
Cobimetinib: (Minor) If concurrent use of cobimetinib and testosterone is necessary, use caution and monitor for a possible increase in cobimetinib-related adverse effects. Cobimetinib is a P-glycoprotein (P-gp) substrate, and testosterone is a P-gp inhibitor; coadministration may result in increased cobimetinib exposure. However, coadministration of cobimetinib with another P-gp inhibitor, vemurafenib (960 mg twice daily), did not result in clinically relevant pharmacokinetic drug interactions. Topical preparations of testosterone are not expected to have this interaction.
Conivaptan: (Major) Avoid coadministration of conivaptan, a CYP3A4/P-glycoprotein (P-gp) inhibitor and testosterone, a CYP3A4/P-gp substrate. Concurrent use may result in elevated testosterone serum concentrations. According to the manufacturer, concomitant use of conivaptan, a strong CYP3A4 inhibitor, and CYP3A substrates, such as testosterone, should be avoided. Coadministration of conivaptan with other CYP3A substrates has resulted in increased mean AUC values (2 to 3 times). Theoretically, similar pharmacokinetic effects could be seen with testosterone. Treatment with testosterone may be initiated no sooner than 1 week after completion of conivaptan therapy.
Corticosteroids: (Moderate) Coadministration of corticosteroids and testosterone may increase the risk of edema, especially in patients with underlying cardiac or hepatic disease. Corticosteroids with greater mineralocorticoid activity, such as fludrocortisone, may be more likely to cause edema. Administer these drugs in combination with caution.
Cyclosporine: (Moderate) Androgens may increase concentrations of cyclosporine, potentially increasing the risk of nephrotoxicity. Until further data are available, close monitoring of cyclosporine serum concentrations is prudent during coadministration with androgens.
Dabigatran: (Moderate) Increased serum concentrations of dabigatran are possible when dabigatran, a P-glycoprotein (P-gp) substrate, is coadministered with testosterone, a P-gp inhibitor. Patients should be monitored for increased adverse effects of dabigatran. When dabigatran is administered for treatment or reduction in risk of recurrence of deep venous thrombosis (DVT) or pulmonary embolism (PE), or prophylaxis of DVT or PE following hip replacement surgery, avoid coadministration with P-gp inhibitors like testosterone in patients with CrCl less than 50 mL/minute. When dabigatran is used in patients with non-valvular atrial fibrillation and severe renal impairment (CrCl less than 30 mL/minute), avoid coadministration with testosterone, as serum concentrations of dabigatran are expected to be higher than when administered to patients with normal renal function. P-gp inhibition and renal impairment are the major independent factors that result in increased exposure to dabigatran.
Daclatasvir: (Minor) Systemic exposure of testosterone, a P-glycoprotein (P-gp) substrate, may be increased when administered concurrently with daclatasvir, a P-gp inhibitor. Taking these drugs together could increase or prolong the therapeutic effects of testosterone; monitor patients for potential adverse effects.
Dapagliflozin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Dapagliflozin; Metformin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Dapagliflozin; Saxagliptin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Darbepoetin Alfa: (Moderate) Androgens are known to stimulate erythropoiesis. Concurrent administration of androgens can increase the patient's response to darbepoetin alfa, reducing the amount required to treat anemia.
Darunavir: (Minor) The plasma concentrations of testosterone may be significantly elevated when administered concurrently with darunavir. Clinical monitoring for adverse effects, such as libido changes and other hormone-induced effects, is recommended during coadministration. Darunavir is an inhibitor of CYP3A4. Testosterone is a CYP3A4 substrate.
Darunavir; Cobicistat: (Minor) Plasma concentrations of testosterone may be significantly elevated when administered with cobicistat. Clinical monitoring for adverse effects, such as libido changes and other hormone-induced effects, is recommended during coadministration. Cobicistat is a CYP3A4 and P-glycoprotein (P-gp) inhibitor, while testosterone is a CYP3A4 and P-gp substrate. (Minor) The plasma concentrations of testosterone may be significantly elevated when administered concurrently with darunavir. Clinical monitoring for adverse effects, such as libido changes and other hormone-induced effects, is recommended during coadministration. Darunavir is an inhibitor of CYP3A4. Testosterone is a CYP3A4 substrate.
Darunavir; Cobicistat; Emtricitabine; Tenofovir alafenamide: (Minor) Plasma concentrations of testosterone may be significantly elevated when administered with cobicistat. Clinical monitoring for adverse effects, such as libido changes and other hormone-induced effects, is recommended during coadministration. Cobicistat is a CYP3A4 and P-glycoprotein (P-gp) inhibitor, while testosterone is a CYP3A4 and P-gp substrate. (Minor) The plasma concentrations of testosterone may be significantly elevated when administered concurrently with darunavir. Clinical monitoring for adverse effects, such as libido changes and other hormone-induced effects, is recommended during coadministration. Darunavir is an inhibitor of CYP3A4. Testosterone is a CYP3A4 substrate.
Dasabuvir; Ombitasvir; Paritaprevir; Ritonavir: (Moderate) Concurrent administration of testosterone with dasabuvir; ombitasvir; paritaprevir; ritonavir may result in elevated plasma concentrations of testosterone, dasabuvir, ombitasvir, paritaprevir, and ritonavir. Testosterone is a substrate of the hepatic isoenzyme CYP3A4 and the drug transporter P-glycoprotein (P-gp). Ritonavir is a potent CYP3A4 inhibitor; it also inhibits P-gp. In addition, testosterone inhibits the drug transporter P-glycoprotein (P-gp); dasabuvir, ombitasvir, paritaprevir and ritonavir are all substrates of P-gp. Caution and close monitoring are advised if these drugs are administered together. (Moderate) Concurrent administration of testosterone with dasabuvir; ombitasvir; paritaprevir; ritonavir or ombitasvir; paritaprevir; ritonavir may result in elevated plasma concentrations of testosterone, dasabuvir, ombitasvir, paritaprevir, and ritonavir. Testosterone is a substrate of the hepatic isoenzyme CYP3A4 and the drug transporter P-glycoprotein (P-gp). Ritonavir is a potent CYP3A4 inhibitor; it also inhibits P-gp. Paritaprevir also inhibits P-gp. In addition, testosterone inhibits the drug transporter P-glycoprotein (P-gp); dasabuvir, ombitasvir, paritaprevir and ritonavir are all substrates of P-gp. Caution and close monitoring are advised if these drugs are administered together. (Moderate) Concurrent administration of testosterone with ritonavir may result in elevated plasma concentrations of testosterone and ritonavir. Testosterone is a substrate of the hepatic isoenzyme CYP3A4 and the drug transporter P-glycoprotein (P-gp). Ritonavir is a CYP3A4 and P-gp inhibitor. In addition, testosterone inhibits P-gp; ritonavir is a substrate of P-gp. Caution and close monitoring are advised if these drugs are administered together.
Degarelix: (Major) Concomitant use of androgens with degarelix is relatively contraindicated, as androgens could counteract the therapeutic effect of degarelix.
Dipeptidyl Peptidase-4 Inhibitors: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Doravirine; Lamivudine; Tenofovir disoproxil fumarate: (Moderate) Caution is advised when administering tenofovir, PMPA, a P-glycoprotein (P-gp) substrate, concurrently with inhibitors of P-gp, such as testosterone. Coadministration may result in increased absorption of tenofovir. Monitor for tenofovir-associated adverse reactions.
Dronedarone: (Moderate) Dronedarone is metabolized by and is an inhibitor of CYP3A; dronedarone also inhibits P-gp. Testosterone is a substrate for CYP3A4 and P-gp. The concomitant administration of dronedarone with CYP3A4 and P-gp substrates may result in increased exposure of the substrate and should, therefore, be undertaken with caution.
Edoxaban: (Moderate) Coadministration of edoxaban and testosterone may result in increased concentrations of edoxaban. Edoxaban is a P-glycoprotein (P-gp) substrate and testosterone is a P-gp inhibitor. Increased concentrations of edoxaban may occur during concomitant use of testosterone; monitor for increased adverse effects of edoxaban. Dosage reduction may be considered for patients being treated for deep venous thrombosis (DVT) or pulmonary embolism.
Efavirenz; Emtricitabine; Tenofovir: (Moderate) Caution is advised when administering tenofovir, PMPA, a P-glycoprotein (P-gp) substrate, concurrently with inhibitors of P-gp, such as testosterone. Coadministration may result in increased absorption of tenofovir. Monitor for tenofovir-associated adverse reactions.
Efavirenz; Lamivudine; Tenofovir Disoproxil Fumarate: (Moderate) Caution is advised when administering tenofovir, PMPA, a P-glycoprotein (P-gp) substrate, concurrently with inhibitors of P-gp, such as testosterone. Coadministration may result in increased absorption of tenofovir. Monitor for tenofovir-associated adverse reactions.
Elbasvir; Grazoprevir: (Minor) Administering testosterone with grazoprevir may result in elevated testosterone plasma concentrations. Testosterone is a substrate of CYP3A; grazoprevir is a weak CYP3A inhibitor. If these drugs are used together, closely monitor for signs of adverse events.
Eliglustat: (Moderate) Coadministration of testosterone and eliglustat may result in increased plasma concentrations of testosterone. Monitor patients closely for testosterone-related adverse effects. Testosterone is a P-glycoprotein (P-gp) substrate; eliglustat is a P-gp inhibitor.
Empagliflozin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Empagliflozin; Linagliptin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Empagliflozin; Metformin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Emtricitabine; Rilpivirine; Tenofovir disoproxil fumarate: (Moderate) Caution is advised when administering tenofovir, PMPA, a P-glycoprotein (P-gp) substrate, concurrently with inhibitors of P-gp, such as testosterone. Coadministration may result in increased absorption of tenofovir. Monitor for tenofovir-associated adverse reactions.
Emtricitabine; Tenofovir disoproxil fumarate: (Moderate) Caution is advised when administering tenofovir, PMPA, a P-glycoprotein (P-gp) substrate, concurrently with inhibitors of P-gp, such as testosterone. Coadministration may result in increased absorption of tenofovir. Monitor for tenofovir-associated adverse reactions.
Epoetin Alfa: (Moderate) Androgens are known to stimulate erythropoiesis. Concurrent administration of androgens can increase the patient's response to epoetin alfa, reducing the amount required to treat anemia. Because adverse reactions have been associated with an abrupt increase in blood viscosity, this drug combination should be avoided, if possible. Further evaluation of this combination needs to be made.
Ertugliflozin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Ertugliflozin; Metformin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Ertugliflozin; Sitagliptin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Etoposide, VP-16: (Major) Monitor for an increased incidence of etoposide-related adverse effects if used concomitantly with testosterone. Testosterone is an inhibitor of P-glycoprotein (P-gp) and etoposide, VP-16 is a P-gp substrate. Coadministration may increase etoposide concentrations.
Everolimus: (Major) Everolimus is an inhibitor and substrate of CYP3A4 and Pgp. Coadministration with inhibitors of Pgp, such as testosterone, is not recommended. Patients may experience an increase in systemic exposure to everolimus if these drugs are coadministered. In addition, testosterone is a substrate of CYP3A4. The effect of everolimus on testosterone pharmacokinetics has not been established; however, pharmacokinetic studies showed no significant impact of the coadministration of everolimus with the CYP3A4 and Pgp substrate atorvastatin.
Fluconazole: (Minor) Testosterone concentrations may increase during fluconazole administration. Fluconazole is an inhibitor of CYP3A4, the hepatic microsomal isoenzyme responsible for metabolism of testosterone. The clinical significance of this interaction is unclear at this time.
Fosamprenavir: (Moderate) Concomitant use of testosterone and fosamprenavir may result in elevated fosamprenavir and altered testosterone plasma concentrations. Testosterone is a substrate of the hepatic isoenzyme CYP3A4 and a substrate/inhibitor of the drug transporter P-glycoprotein (P-gp). Amprenavir, the active metabolite of fosamprenavir, is substrate/inducer of P-gp and a potent inhibitor/moderate inducer of CYP3A4.
Glipizide; Metformin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Glyburide; Metformin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Goserelin: (Major) Goserelin inhibits steroidogenesis. Concomitant use of androgens, like fluoxymesterone, with goserelin is relatively contraindicated and would defeat the purpose of goserelin therapy.
Histrelin: (Major) Avoid concurrent use of androgens with gonadotropin releasing hormone (GnRH) agonists such as histrelin. Histrelin inhibits steroidogenesis; concomitant use with androgens may counteract this therapeutic effect.
Hydrochlorothiazide, HCTZ; Propranolol: (Moderate) Testosterone cypionate has been shown to increase the clearance of propranolol in one study. Monitor patients taking testosterone and propranolol together for decreased therapeutic efficacy of propranolol.
Idelalisib: (Major) Avoid concomitant use of idelalisib, a strong CYP3A inhibitor, with testosterone, a CYP3A substrate, as testosterone toxicities may be significantly increased. The AUC of a sensitive CYP3A substrate was increased 5.4-fold when coadministered with idelalisib.
Incretin Mimetics: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Insulins: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Isavuconazonium: (Moderate) The plasma concentrations of testosterone may be elevated when administered concurrently with isavuconazonium. Clinical monitoring for adverse effects, such as libido changes and other hormone-induced effects, is recommended during coadministration. Testosterone is a substrate of the hepatic isoenzyme CYP3A4 and drug transporter P-glycoprotein (P-gp); isavuconazole, the active moiety of isavuconazonium, is an inhibitor of CYP3A4 and P-gp.
Ixabepilone: (Minor) Testosterone is an inhibitor of and substrate for P-glycoprotein (Pgp). Ixabepilone is a mild inhibitor of and substrate for Pgp. Concomitant use of these agents may cause an increase in ixabepilone concentrations and/or an increase in testosterone concentrations. Caution is recommended if ixabepilone is coadministered with a Pgp inhibitor.
Lamivudine; Tenofovir Disoproxil Fumarate: (Moderate) Caution is advised when administering tenofovir, PMPA, a P-glycoprotein (P-gp) substrate, concurrently with inhibitors of P-gp, such as testosterone. Coadministration may result in increased absorption of tenofovir. Monitor for tenofovir-associated adverse reactions.
Leuprolide: (Major) Leuprolide inhibits steroidogenesis. While no drug interactions have been reported with leuprolide, therapy with androgens would be relatively contraindicated and would counteract the therapeutic effect of leuprolide.
Leuprolide; Norethindrone: (Major) Leuprolide inhibits steroidogenesis. While no drug interactions have been reported with leuprolide, therapy with androgens would be relatively contraindicated and would counteract the therapeutic effect of leuprolide.
Linagliptin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Linagliptin; Metformin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Loperamide: (Moderate) The plasma concentration of loperamide, a P-glycoprotein (P-gp) substrate, may be increased when administered concurrently with testosterone, a P-gp inhibitor. If these drugs are used together, monitor for loperamide-associated adverse reactions, such as CNS effects and cardiac toxicities (i.e., syncope, ventricular tachycardia, QT prolongation, torsade de pointes, cardiac arrest).
Loperamide; Simethicone: (Moderate) The plasma concentration of loperamide, a P-glycoprotein (P-gp) substrate, may be increased when administered concurrently with testosterone, a P-gp inhibitor. If these drugs are used together, monitor for loperamide-associated adverse reactions, such as CNS effects and cardiac toxicities (i.e., syncope, ventricular tachycardia, QT prolongation, torsade de pointes, cardiac arrest).
Lopinavir; Ritonavir: (Moderate) Concurrent administration of testosterone with lopinavir; ritonavir may result in elevated plasma concentrations of testosterone and ritonavir. Testosterone is a substrate of the hepatic isoenzyme CYP3A4 and the drug transporter P-glycoprotein (P-gp). Ritonavir is a CYP3A4 and P-gp inhibitor, while lopinavir also inhibits P-gp. In addition, testosterone inhibits P-gp; ritonavir is a substrate of P-gp. Caution and close monitoring are advised if these drugs are administered together. (Moderate) Concurrent administration of testosterone with ritonavir may result in elevated plasma concentrations of testosterone and ritonavir. Testosterone is a substrate of the hepatic isoenzyme CYP3A4 and the drug transporter P-glycoprotein (P-gp). Ritonavir is a CYP3A4 and P-gp inhibitor. In addition, testosterone inhibits P-gp; ritonavir is a substrate of P-gp. Caution and close monitoring are advised if these drugs are administered together.
Lumacaftor; Ivacaftor: (Minor) Lumacaftor; ivacaftor may alter the exposure of testosterone. Testosterone is a substrate of CYP3A and the P-glycoprotein (P-gp) drug transporter. Lumacaftor is a strong CYP3A inducer; in vitro data suggest lumacaftor; ivacaftor may also induce and/or inhibit P-gp. Although induction of testosterone metabolism through the CYP3A pathway may lead to decreased drug efficacy, the net effect of lumacaftor; ivacaftor on P-gp transport is not clear.
Maraviroc: (Moderate) Use caution and careful monitoring with the coadministration of maraviroc and testosterone as increased maraviroc concentrations may occur. Maraviroc is a substrate of P-glycoprotein (P-gp); testosterone is an inhibitor of P-gp. The effects of P-gp on the concentrations of maraviroc are unknown, although an increase in concentrations and thus, toxicity, are possible.
Meglitinides: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Metformin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Metformin; Pioglitazone: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Metformin; Repaglinide: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Metformin; Rosiglitazone: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Metformin; Saxagliptin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Metformin; Sitagliptin: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Methoxy polyethylene glycol-epoetin beta: (Moderate) Androgens are known to stimulate erythropoiesis. Despite the fact that endogenous generation of erythropoietin is depressed in patients with chronic renal failure, other tissues besides the kidney can synthesize erythropoietin, albeit in small amounts. Concurrent administration of androgens can increase the patient's response to MPG-epoetin beta, reducing the amount required to treat anemia. Because adverse reactions have been associated with an abrupt increase in blood viscosity, this drug combination should be avoided, if possible. Further evaluation of this combination needs to be made.
Miglitol: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Mitotane: (Moderate) Use caution if mitotane and testosterone are used concomitantly, and monitor for decreased efficacy of testosterone and a possible change in dosage requirements. Mitotane is a strong CYP3A4 inducer and testosterone is a CYP3A4 substrate; coadministration may result in decreased plasma concentrations of testosterone. Topical preparations of testosterone are not expected to have this interaction.
Nafarelin: (Major) Gonadotropin releasing hormone (GnRH) agonists (i.e.,nafarelin) inhibit steroidogenesis, therefore the concomitant use of these agents with androgens may counteract this therapeutic effect. Avoid concurrent use of androgens with GnRH agonists.
Nanoparticle Albumin-Bound Paclitaxel: (Minor) Paclitaxel is metabolized by hepatic cytochrome P450 (CYP) isoenzymes 2C8 and 3A4. Testosterone inhibited the formation of paclitaxel metabolites in vitro. Combining the drugs in clinical practice may require close monitoring to ensure proper therapeutic responses.
Ombitasvir; Paritaprevir; Ritonavir: (Moderate) Concurrent administration of testosterone with dasabuvir; ombitasvir; paritaprevir; ritonavir may result in elevated plasma concentrations of testosterone, dasabuvir, ombitasvir, paritaprevir, and ritonavir. Testosterone is a substrate of the hepatic isoenzyme CYP3A4 and the drug transporter P-glycoprotein (P-gp). Ritonavir is a potent CYP3A4 inhibitor; it also inhibits P-gp. In addition, testosterone inhibits the drug transporter P-glycoprotein (P-gp); dasabuvir, ombitasvir, paritaprevir and ritonavir are all substrates of P-gp. Caution and close monitoring are advised if these drugs are administered together. (Moderate) Concurrent administration of testosterone with dasabuvir; ombitasvir; paritaprevir; ritonavir or ombitasvir; paritaprevir; ritonavir may result in elevated plasma concentrations of testosterone, dasabuvir, ombitasvir, paritaprevir, and ritonavir. Testosterone is a substrate of the hepatic isoenzyme CYP3A4 and the drug transporter P-glycoprotein (P-gp). Ritonavir is a potent CYP3A4 inhibitor
Oritavancin:
(Minor) Testosterone is metabolized by CYP3A4; oritavancin is a weak CYP3A4 inducer. Plasma concentrations and efficacy of testosterone may be reduced if these drugs are administered concurrently.
Oxymetazoline:
(Moderate) The drug interaction potential between intranasal testosterone (e.g., Natesto) and other intranasally administered drugs other than sympathomimetic decongestants is unknown. Therefore, concomitant use of intranasal testosterone with intranasal drugs other than sympathomimetic decongestants (e.g., oxymetazoline) is not recommended. Eighteen males with seasonal allergic rhinitis were treated with intranasal testosterone and randomized to receive oxymetazoline (30 minutes prior to intranasal testosterone) or no treatment. In general, serum total testosterone concentrations were decreased by 21-24% in males with symptomatic allergic rhinitis, due to the underlying condition. A mean decrease in AUC and Cmax (2.6% and 3.6%, respectively) for total testosterone was observed in males with symptomatic seasonal rhinitis when treated with oxymetazoline compared to untreated patients. Concomitant use of oxymetazoline does not impact the absorption of testosterone.
Pazopanib:
(Moderate) Pazopanib is a weak inhibitor of CYP3A4 and a substrate for P-glycoprotein (Pgp). Testosterone is a substrate for CYP3A4 and an inhibitor of Pgp. Concurrent administration of testosterone and pazopanib may result in increased pazopanib concentrations and/or increased testosterone concentrations. Use caution when concurrent administration of testosterone and pazopanib is necessary.
Posaconazole:
(Major) Posaconazole and testosterone should be coadministered with caution due to an increased potential for adverse events. This complex interaction may cause alterations in the plasma concentrations of both posaconazole and testosterone, ultimately resulting in an increased risk of adverse events. Posaconazole is a potent inhibitor of CYP3A4, an isoenzyme partially responsible for the metabolism of testosterone. Further, both testosterone and posaconazole are inhibitors and substrates of the drug efflux protein, P-glycoprotein, which when administered together may increase the absorption or decrease the clearance of the other drug.
Pramlintide:
(Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Propranolol:
(Moderate) Testosterone cypionate has been shown to increase the clearance of propranolol in one study. Monitor patients taking testosterone and propranolol together for decreased therapeutic efficacy of propranolol.
Ranolazine:
(Moderate) Testosterone is an inhibitor of P-glycoprotein transport. Ranolazine is a substrate of P-glycoprotein, and inhibitors of P-glycoprotein may increase the absorption of ranolazine. In addition, ranolazine inhibits CYP3A and may increase plasma concentrations of drugs that are primarily metabolized by CYP3A4 such as testosterone.
Rifaximin:
(Moderate) Although the clinical significance of this interaction is unknown, concurrent use of rifaximin, a P-glycoprotein (P-gp) substrate, and testosterone, a P-gp inhibitor, may substantially increase the systemic exposure to rifaximin; caution is advised if these drugs must be administered together. During one in vitro study, coadministration with cyclosporine, a potent P-gp inhibitor, resulted in an 83-fold and 124-fold increase in the mean Cmax and AUC of rifaximin, respectively. In patients with hepatic impairment, the effects of reduced metabolism and P-gp inhibition may further increase exposure to rifaximin.
Ritonavir:
(Moderate) Concurrent administration of testosterone with ritonavir may result in elevated plasma concentrations of testosterone and ritonavir. Testosterone is a substrate of the hepatic isoenzyme CYP3A4 and the drug transporter P-glycoprotein (P-gp). Ritonavir is a CYP3A4 and P-gp inhibitor. In addition, testosterone inhibits P-gp; ritonavir is a substrate of P-gp. Caution and close monitoring are advised if these drugs are administered together.
Rivaroxaban:
(Minor) Coadministration of rivaroxaban and testosterone may result in increases in rivaroxaban exposure and may increase bleeding risk. Testosterone is an inhibitor of P-gp, and rivaroxaban is a substrate of P-gp. If these drugs are administered concurrently, monitor the patient for signs and symptoms of bleeding.
Romidepsin:
(Moderate) Romidepsin is a substrate for P-glycoprotein. Testosterone is an inhibitor of P-gp. Concurrent administration of romidepsin with an inhibitor of P-gp may cause an increase in systemic romidepsin concentrations. Use caution when concomitant administration of these agents is necessary.
Sapropterin:
(Minor) Caution is advised with the concomitant use of sapropterin and testosterone as coadministration may result in increased systemic exposure of testosterone. Testosterone is a substrate for the drug transporter P-glycoprotein (P-gp); in vitro data show that sapropterin may inhibit P-gp. If these drugs are used together, closely monitor for increased side effects of testosterone.
Saw Palmetto, Serenoa repens:
(Major) Drug interactions with Saw palmetto, Serenoa repens have not been specifically studied or reported. Saw palmetto extracts appear to have antiandrogenic effects. The antiandrogenic effects of Saw palmetto, Serenoa repens would be expected to antagonize the actions of androgens; it would seem illogical for patients taking androgens to use this herbal supplement.
Saxagliptin:
(Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
SGLT2 Inhibitors:
(Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Simvastatin; Sitagliptin:
(Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Sitagliptin:
(Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Sofosbuvir; Velpatasvir:
(Moderate) Use caution when administering velpatasvir with testosterone. Taking these medications together may increase the plasma concentrations of both drugs, potentially resulting in adverse events. Both drugs are substrates and inhibitors of the drug transporter P-glycoprotein (P-gp).
Sofosbuvir; Velpatasvir; Voxilaprevir:
(Moderate) Plasma concentrations of testosterone, a P-glycoprotein (P-gp) substrate, may be increased when administered concurrently with voxilaprevir, a P-gp inhibitor. Monitor patients for increased side effects if these drugs are administered concurrently. (Moderate) Use caution when administering velpatasvir with testosterone. Taking these medications together may increase the plasma concentrations of both drugs, potentially resulting in adverse events. Both drugs are substrates and inhibitors of the drug transporter P-glycoprotein (P-gp).
Somatropin, rh-GH:
(Moderate) Somatropin can induce (i.e., increase) the activity of cytochrome-mediated metabolism of antipyrine clearance in man. Thus, this predicts that somatropin may affect other drugs metabolized via this pathway, like testosterone.
Soy Isoflavones:
(Moderate) Theoretically, the soy isoflavones may counteract the activity of the androgens.
St. John's Wort, Hypericum perforatum:
(Moderate) St. John's Wort appears to induce several isoenzymes of the hepatic cytochrome P450 enzyme system, including CYP3A4, CYP1A2, and potentially CYP2C9. Co-administration of St. John's Wort could decrease the efficacy of some medications metabolized by these enzymes, including testosterone.
Sulfonylureas:
(Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Telaprevir:
(Moderate) Close clinical monitoring is advised when administering testosterone with telaprevir due to an increased potential for testosterone-related adverse events. Coadministration may result in elevated testosterone plasma concentrations. If testosterone dose adjustments are made, re-adjust the dose upon completion of telaprevir treatment. Although this interaction has not been studied, predictions about the interaction can be made based on the metabolic pathway of testosterone. Testosterone is a substrate of the drug efflux transporter P-glycoprotein (P-gp) and of the hepatic isoenzyme CYP3A4; telaprevir is an inhibitor of both the efflux protein and the isoenzyme.
Telotristat Ethyl:
(Moderate) Use caution if coadministration of telotristat ethyl and testosterone is necessary, as the systemic exposure of testosterone may be decreased resulting in reduced efficacy; exposure to telotristat ethyl may also be increased. If these drugs are used together, monitor patients for suboptimal efficacy of testosterone as well as an increase in adverse reactions related to telotristat ethyl. Consider increasing the dose of testosterone if necessary. Testosterone is a CYP3A4 substrate. The mean Cmax and AUC of another sensitive CYP3A4 substrate was decreased by 25% and 48%, respectively, when coadministered with telotristat ethyl; the mechanism of this interaction appears to be that telotristat ethyl increases the glucuronidation of the CYP3A4 substrate. Additionally, the active metabolite of telotristat ethyl, telotristat, is a substrate of P-glycoprotein (P-gp) and testosterone is a P-gp inhibitor. Exposure to telotristat ethyl may increase.
Tenofovir Alafenamide:
(Minor) Caution is advised when administering tenofovir alafenamide concurrently with testosterone, as coadministration may result in elevated tenofovir alafenamide plasma concentrations. Inhibitors of the drug transporter P-glycoprotein (P-gp), such as testosterone, may increase absorption of tenofovir alafenamide, a P-gp substrate. If these medications are administered together, monitor for tenofovir-associated adverse reactions. Of note, when tenofovir alafenamide is administered as part of a cobicistat-containing product, its availability is increased by cobicistat and a further increase of tenofovir alafenamide concentrations is not expected upon coadministration of an additional P-gp inhibitor.
Tenofovir, PMPA:
(Moderate) Caution is advised when administering tenofovir, PMPA, a P-glycoprotein (P-gp) substrate, concurrently with inhibitors of P-gp, such as testosterone. Coadministration may result in increased absorption of tenofovir. Monitor for tenofovir-associated adverse reactions.
Thiazolidinediones:
(Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
Ticagrelor:
(Moderate) Coadministration of ticagrelor and testosterone may result in increased exposure to ticagrelor which may increase the bleeding risk. Ticagrelor is a P-glycoprotein (P-gp) substrate and testosterone is a P-gp inhibitor. Based on drug information data with cyclosporine, no dose adjustment is recommended by the manufacturer of ticagrelor. Use combination with caution and monitor for evidence of bleeding.
Tolvaptan:
(Major) Tolvaptan is a substrate for P-gp. Testosterone is an inhibitor of P-gp. Coadministration may result in increased exposure of tolvaptan; a reduction in the dose of tolvaptan may be required.
Triptorelin:
(Major) Gonadotropin releasing hormone (GnRH) agonists (i.e.,triptorelin) inhibit steroidogenesis, therefore the concomitant use of these agents with androgens may counteract this therapeutic effect. Avoid concurrent use of androgens with GnRH agonists.
Vandetanib: (Moderate) Use caution if coadministration of vandetanib with testosterone is necessary, due to a possible increase in testosterone-related adverse reactions. Testosterone is a partial substrate of P-glycoprotein (P-gp). Coadministration with vandetanib increased the Cmax and AUC of another P-gp substrate by 29% and 23%, respectively. This interaction is not expected for topical preparations of testosterone.
Vemurafenib: (Moderate) Concomitant use of vemurafenib and testosterone may result in altered concentrations of testosterone and increased concentrations of vemurafenib. Vemurafenib is a substrate/inducer of CYP3A4 and a substrate/inhibitor of P-glycoprotein (PGP).Testosterone is a substrate of CYP3A4 and a substrate/inhibitor of PGP. Use caution and monitor patients for toxicity and efficacy.
Vinblastine: (Minor) Testosterone is an inhibitor of the efflux transporter P-glycoprotein. Vinblastine is a P-glycoprotein substrate. Increased concentrations of vinblastine are likely if it is coadministered with testosterone; exercise caution.
Vincristine Liposomal: (Major) Testosterone inhibits P-glycoprotein (P-gp), and vincristine is a P-gp substrate. Coadministration could increase exposure to vincristine; monitor patients for increased side effects if these drugs are given together.
Vincristine: (Major) Testosterone inhibits P-glycoprotein (P-gp), and vincristine is a P-gp substrate. Coadministration could increase exposure to vincristine; monitor patients for increased side effects if these drugs are given together.
Voriconazole: (Minor) Limited data suggest that testosterone concentrations increase during fluconazole administration. Although data are not available, a similar reaction may occur with voriconazole. Also, voriconazole is an inhibitor of CYP3A4, the hepatic microsomal isoenzyme responsible for metabolism of testosterone.
Warfarin: (Moderate) Testosterone can increase the anticoagulant action of warfarin. Serious bleeding has been reported in some patients with this drug-drug interaction. Although the mechanism is unclear, testosterone may reduce procoagulant factors. Reduction of warfarin dosage may be necessary if testosterone therapy is coadministered. More frequent monitoring of INR and prothrombin time in patients taking such oral anticoagulants is recommended, especially at the initiation and termination of androgen therapy. It is unclear if testosterone can augment the anticoagulant response to heparin therapy or if testosterone alters the effect of other non-coumarin oral anticoagulants in a similar manner.
Zonisamide: (Minor) Zonisamide is a weak inhibitor of P-glycoprotein (P-gp), and testosterone is a substrate of P-gp. There is theoretical potential for zonisamide to affect the pharmacokinetics of drugs that are P-gp substrates. Use caution when starting or stopping zonisamide or changing the zonisamide dosage in patients also receiving drugs which are P-gp substrates.
Reference: Depo-Testosterone (testosterone cypionate) dose, indications, adverse effects, interactions... from PDR.net
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