Alprostadil: ingredient and formulations

Alprostadil belongs to a different medicine family from oral PDE5 inhibitors. It is prostaglandin E1 and relaxes smooth muscle in erectile tissue. Its route of delivery changes the practical treatment, side effects and interpretation of the evidence.

Key points

• Cream, injection and intraurethral preparations are separate treatments, not dose-conversion options.
• Local delivery avoids taking an oral PDE5 tablet, but does not remove the need for medical assessment.
• Cream-study results should not inherit injection success rates.
• Training, local discomfort, partner exposure and follow-up can determine whether a route is workable.
• This catalogue currently profiles Vitaros cream; the ingredient overview has broader scope.

Three routes, three sets of questions

Vitaros cream uses a single-use container and has product-specific application instructions. The UK information requires instruction by a medical professional. Local burning, pain or irritation can matter to the user, and a partner can experience vaginal irritation. Its label includes barrier-protection advice and pregnancy-related precautions.

Intracavernosal injection delivers alprostadil into erectile tissue. The Caverject UK label requires supervised selection of treatment amounts, initial injections by trained personnel and an assessment of competence before home use. Injection-site bleeding, penile pain and fibrosis require a different discussion from cream irritation. Regular examination and follow-up are part of that treatment context.

Intraurethral products deliver a preparation into the urethra. Their applicator, amounts and precautions are specific to that route. An Irish MUSE leaflet retrieved here provides a route-specific reference, but its dated document does not establish current stock or availability. None of these routes should be improvised using another presentation’s instructions.

The cream evidence: modest average improvement

A pooled analysis of two randomized trials included 1,732 men treated for twelve weeks with placebo or three investigated cream amounts. Mean changes in the erectile-function questionnaire were −0.7 points with placebo and 1.6, 2.5 and 2.4 with the active treatments. Penetration and erection-maintenance measures also improved slightly but significantly relative to placebo.

The distinction between statistical and practical benefit matters. The study found a treatment effect, but its average questionnaire changes were modest. It does not say that every participant achieved satisfactory intercourse or that cream is as effective as injection. Most reported adverse events were local and resolved within two hours in the trial, which does not eliminate all local or systemic risks for an individual.

The intraurethral study: notice who was randomized

A 1997 trial first tested 1,511 men in the clinic. About 65.9% achieved an erection sufficient for intercourse during that testing. Men with an adequate response were then assigned to active treatment or placebo for home use over three months.

Among those who reported at least one home treatment, successful intercourse at least once occurred in 64.9% with alprostadil versus 18.6% with placebo. Those home-treatment percentages concern preselected responders, not all 1,511 men initially assessed. The study is therefore useful evidence for that route, but a poor basis for promising a universal success rate or attributing the same result to Vitaros cream.

Suitability is more than avoiding an oral tablet

Local alprostadil can cause dizziness or low blood pressure as well as route-specific discomfort. Prolonged erections need urgent assessment. Penile conditions, bleeding risk, cardiovascular suitability and the ability to use the device correctly can affect the choice. A person’s partner may also have relevant questions about exposure and protection.

The UK Vitaros information advises against combination with PDE5 inhibitors because safety and efficacy of that combination have not been established for the product. The injection label likewise has combination restrictions. A different mechanism does not make unsupervised addition to an ED tablet a routine solution.

The decision is a comparison of desired benefit, delivery burden, training, tolerability and the applicable product record. This page explains those tradeoffs without teaching an administration technique.

Sources

5 sources

Checked October 4, 2026.

1. Vitaros UK product information — emc
2. Caverject UK product information — emc
3. Pooled topical alprostadil trials — Urology, 2006
4. Intraurethral alprostadil randomized trial — New England Journal of Medicine, 1997
5. MUSE route-specific information (dated document) — HPRA, Ireland