What dose did you use?
Here's a comprehensive side-by-side comparison of
Caverject and
Invicorp:
Caverject vs. Invicorp: Full Comparison
Active Ingredients & Mechanism
| Caverject (alprostadil) | Invicorp (aviptadil + phentolamine) | |
|---|
| Active ingredient(s) | Alprostadil (synthetic PGE1) | Aviptadil (synthetic VIP) + Phentolamine mesilate |
| Drug class | Prostaglandin E1 agonist | VIP analogue + alpha-adrenergic antagonist |
| Mechanism | Smooth muscle relaxant; vasodilator that increases arterial inflow and reduces venous outflow | Dual complementary action: phentolamine increases arterial inflow; aviptadil reduces venous outflow |
| Number of agents | Single agent | Combination (two agents) |
The two active components of Invicorp have complementary mechanisms: phentolamine mesilate increases the flow of blood into the penis, while aviptadil reduces the flow of blood from the penis. This is a fundamentally different pharmacological approach compared to alprostadil's single-agent action.
Inactive Ingredients (Excipients)
Caverject (standard vial): Inactive ingredients include lactose, sodium citrate, benzyl alcohol (contained in the final solution), and hydrochloric acid and/or sodium hydroxide for pH adjustment.
Caverject Impulse (pre-filled dual-chamber device): Inactive ingredients: alpha cyclodextrin, lactose, sodium citrate, benzyl alcohol, and hydrochloric and/or sodium hydroxide for pH adjustment. Note the addition of alpha-cyclodextrin as a solubilizing agent in the Impulse formulation.
Invicorp: The other ingredients are sodium chloride, disodium edetate, phosphoric acid, hydrochloric acid, sodium hydroxide, and water for injections.
Key difference: Invicorp uses
disodium edetate (EDTA, a chelating/stabilizing agent) and
sodium chloride as its base excipients, making it a ready-to-use aqueous solution — no reconstitution required. Caverject is a lyophilized powder requiring reconstitution.
Formulation & Preparation
| Caverject | Invicorp | |
|---|
| Form | Lyophilized powder — requires reconstitution | Ready-to-use sterile solution |
| Volume | 1 mL reconstituted | 0.35 mL per ampoule |
| Container | Glass vial (or dual-chamber syringe for Impulse) | Light brown glass ampoule |
| Diluent needed | Bacteriostatic water for injection (benzyl alcohol 0.945%) | None |
| Strengths | 5, 10, 20, or 40 mcg alprostadil per vial | Fixed: 25 mcg aviptadil + 2 mg phentolamine |
The deliverable amount of alprostadil is 5, 10, 20, or 40 micrograms per milliliter, with a small amount lost due to adsorption to the vial and syringe.
Dosing
| Caverject | Invicorp | |
|---|
| Starting dose | 1.25–2.5 mcg (neurogenic); 2.5 mcg (vasculogenic/psychogenic) | 25 mcg/2 mg (fixed) or half-dose 12.5 mcg/1 mg |
| Titration visits | Minimum 3 clinic visits for dose titration | 1 clinic visit typically sufficient |
| Max dose | 60 mcg | One injection per day at fixed dose |
| Frequency | No more than 3x/week | No more than 1x/day |
Invicorp offers savings from not requiring 3 dose titration visits — only one appointment is required.
Efficacy
| Caverject | Invicorp | |
|---|
| Overall efficacy | ~87% erections satisfactory for intercourse | >80% of men achieve adequate erection |
| In alprostadil non-responders | N/A (first-line ICI) | 61–63% success rate |
| Onset | 5–20 minutes | 5–10 minutes |
| Duration | Up to 1 hour | ~1 hour; may subside naturally after ejaculation |
Clinical studies showed that Invicorp is effective in ≥80% of men with ED, including those who have failed to respond to other therapies.
Aviptadil/phentolamine 25 mcg/2 mg is regarded as equally efficacious to alprostadil 20 mcg, based on evidence from the VP 007 trial and supported by clinical expert opinion.
Safety & Side Effects
| Side Effect | Caverject | Invicorp |
|---|
| Penile pain | 37% reported at least once | Virtually none reported |
| Priapism risk | ~0.4% (priapism >6 hrs); 4% prolonged erection | Rare; ~50% lower than alprostadil |
| Penile fibrosis | Up to 7.8% with long-term use (18 months) | Lower (less local inflammation) |
| Facial flushing | Uncommon | Common (37–53%) — systemic VIP effect |
| Dizziness/hypotension | ~1% | Present (VIP vasodilatory effect) |
| Hematoma/ecchymosis | 3–4% | ~20% bruising reported |
| Injection site pain | Frequent | Minimal penile pain; some needle pain |
In clinical studies, penile pain after Caverject was reported at least once by 37% of patients, and the frequency of prolonged erection was 4%, while priapism occurred in 0.4%.
Invicorp users did not experience penile pain after the injection and experienced a 50% reduction in incidence of priapism compared to alprostadil.
The main trade-off with Invicorp is systemic vasodilation: minor side effects with Invicorp include transient facial flushing in 53% of patients, truncal flushing in 9%, bruising in 20%, and pain from the injection needle in 11%, with no patients reporting priapism or other serious adverse events in one study.
Contraindications
Both drugs share most contraindications (sickle cell disease, leukemia, multiple myeloma, penile implants, conditions where sex is inadvisable). Key difference:
Invicorp is contraindicated in patients taking heparin or oral anticoagulants. Other contraindications are the same as with alprostadil. Caverject also advises caution with anticoagulants but is less absolute in its labeling.
Storage
| Caverject | Invicorp | |
|---|
| Storage | Room temperature before reconstitution; use within 24 hrs after mixing | Refrigerator 2–8°C; do not freeze |
Regulatory Status
| Caverject | Invicorp | |
|---|
| US FDA approved | Yes (1995) | No — not FDA-approved; available in Europe (Denmark, UK, etc.) |
| Manufacturer | Pfizer | Evolan Pharma AB (Sweden) |
| Place in therapy | Second-line (after PDE5i failure) | Third-line (after alprostadil failure or intolerance) |
Bottom Line for Clinical Practice
Choose Caverject when: the patient is new to ICI therapy, FDA-approval matters (US), and flexible dosing titration is needed.
Choose Invicorp when: the patient has failed or cannot tolerate alprostadil due to
penile pain, or when priapism risk needs to be minimized. Invicorp offers an effective and acceptable third-line option for men who have failed most non-surgical treatment for ED, with the largest study to date showing 63% efficacy in this refractory population.
