CYP3A interactions with TRT Meds

Thread starter #1
I sent @Dr Justin Saya MD (my doc) a message, but not sure how soon he'll be able to respond.

I am being put on a cancer med that interacts/has interaction warnings with CYP3A4 and CYP3A5. I have searched around the web and found precious few references for any contraindications or interactions with the TRT drugs I take. Have found no evidence whatsoever for discontinuing or adjusting doses.

Does anyone know of any other info, have references regarding CYP3A and:
-Testosterone cypionate

-HCG
-DHEA
-Pregnenelone
-Anastrozole
 
#2
I sent @Dr Justin Saya MD (my doc) a message, but not sure how soon he'll be able to respond.

I am being put on a cancer med that interacts/has interaction warnings with CYP3A4 and CYP3A5. I have searched around the web and found precious few references for any contraindications or interactions with the TRT drugs I take. Have found no evidence whatsoever for discontinuing or adjusting doses.

Does anyone know of any other info, have references regarding CYP3A and:
-Testosterone cypionate

-HCG
-DHEA
-Pregnenelone
-Anastrozole
Didn’t get the message just yet, but came across your post. Your new medication is an inducer or inhibitor of CYP450 3A4? T cyp and anastrozole are metabolized (hydroxylated for anastrozole) by CYP450 3A4.
 
Thread starter #3
Thanks Dr Saya, LOL! I wish the message had reached you directly, but glad to know it hasn't, I wouldn;t have known otherwise. Message sent to your email this morning, perhaps blocked on your end due to attachment or included link? Should I re-send?

I believe the doctor said Venetoclax in an inducer, but this document says substrate, Page 5 http://www.bccancer.bc.ca/drug-database-site/Drug Index/Venetoclax_monograph.pdf

There are some contraindications for inhibitors, and strong inducers. I think that the metabolic clearance of T and anastrozole are not at issue unless they are inhibitors or strong inducers. Sounds like you are concerned with how the Venetoclax affect the hormone drugs and the onc is concerned with the effect of the hormone drugs on the venetoclax! I reckon both are on the table!

https://www.rxabbvie.com/pdf/venclexta.pdf
Dosage modifications for CYP3A: section 2.4 PDF page 9
Contraindications CYP3A: Section 4 PDF page 11
CYP3A inhibitors and tumor Lysis: Section 5.1 paragraph 5 PDF page 11
Drug interactions: Section 7.1 PDF page 26
Metabolism: PDF page 31
Other in vitro study info: PDF page 32


EDIT: Also: Quantitative Prediction of the Effect of CYP3A Inhibitors and Inducers on Venetoclax Pharmacokinetics Using a Physiologically Based Pharmacokinetic Model: Journal of Clinical Pharmacology | Request PDF
 
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#4
Thanks Dr Saya, LOL! I wish the message had reached you directly, but glad to know it hasn't, I wouldn;t have known otherwise. Message sent to your email this morning, perhaps blocked on your end due to attachment or included link? Should I re-send?

I believe the doctor said Venetoclax in an inducer, but this document says substrate, Page 5 http://www.bccancer.bc.ca/drug-database-site/Drug Index/Venetoclax_monograph.pdf

There are some contraindications for inhibitors, and strong inducers. I think that the metabolic clearance of T and anastrozole are not at issue unless they are inhibitors or strong inducers. Sounds like you are concerned with how the Venetoclax affect the hormone drugs and the onc is concerned with the effect of the hormone drugs on the venetoclax! I reckon both are on the table!

https://www.rxabbvie.com/pdf/venclexta.pdf
Dosage modifications for CYP3A: section 2.4 PDF page 9
Contraindications CYP3A: Section 4 PDF page 11
CYP3A inhibitors and tumor Lysis: Section 5.1 paragraph 5 PDF page 11
Drug interactions: Section 7.1 PDF page 26
Metabolism: PDF page 31
Other in vitro study info: PDF page 32


EDIT: Also: Quantitative Prediction of the Effect of CYP3A Inhibitors and Inducers on Venetoclax Pharmacokinetics Using a Physiologically Based Pharmacokinetic Model: Journal of Clinical Pharmacology | Request PDF
Checked junk folder and sure enough your email from earlier today was there...something must have triggered the filter.

Nonetheless, I wouldn’t worry. Your medication and some components of HRT are CYP 3A4 substrates, but not significant inhibitors or inducers. You shouldn’t have any issues.
 
Thread starter #5
Checked junk folder and sure enough your email from earlier today was there...something must have triggered the filter.

Nonetheless, I wouldn’t worry. Your medication and some components of HRT are CYP 3A4 substrates, but not significant inhibitors or inducers. You shouldn’t have any issues.
Thank you sir! I'll pass this onto my oncologist.
 
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