Alprostadil review
The second-line option that works when pills don't
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Written by J. Porter, MPH
Medically reviewed by R. Okafor, PharmD
Last reviewed
The short version
Alprostadil is not a pill and not a PDE5 inhibitor. Delivered by injection into the penis or as a urethral suppository, it dilates blood vessels directly rather than amplifying the body's own signal — which means it can work when PDE5 inhibitors have failed, including after prostate surgery or nerve damage.
Best for: People for whom oral PDE5 inhibitors have failed or are contraindicated.
What works
- Works independently of nerve signaling, so it can succeed where pills fail
- Very fast onset
- An option for people who cannot take PDE5 inhibitors
- High response rates in clinical use
What to watch
- Requires self-injection or a urethral suppository
- Penile pain or aching is a common complaint
- Higher risk of prolonged erection than oral medications
- The first dose must be given and titrated in a clinical setting
Get emergency help for these
- An erection lasting more than 4 hours — this can cause permanent damage
- Sudden loss of vision or hearing
- Chest pain during or after sex — tell responders you took a PDE5 inhibitor
At a glance
- Generic name
- Alprostadil
- Brand name
- Caverject / MUSE
- Drug class
- Prostaglandin E1 (non-PDE5)
- FDA approved
- 1995
- Typical doses
- Individually titrated under medical supervision
- Usual starting dose
- Determined by an in-office test dose, not self-selected
- Onset
- 5–20 minutes
- Duration
- 30–60 minutes
- Half-life
- Minutes — it is metabolized very rapidly
- Effect of food
- None — it is not taken orally
- Generic available
- Yes
- Typical cost
- Varies widely by formulation and pharmacy; often costly without coverageChecked July 15, 2026. Prices vary widely by pharmacy — treat as a ballpark, not a quote.
A different mechanism entirely
Every drug on the rest of this page works by amplifying a signal your body produces during arousal. If that signal is absent — because of nerve damage from prostate surgery, advanced diabetes, or spinal injury — there may be nothing for a PDE5 inhibitor to amplify.
Alprostadil is a synthetic form of prostaglandin E1. It relaxes the smooth muscle and dilates the arteries of the penis directly, without needing the nitric oxide signal. That is why it remains effective for many people whose pills have stopped working, and why it is standard second-line therapy in urology practice.
Two delivery routes
| Intracavernosal injection | Intraurethral suppository | |
|---|---|---|
| Brand examples | Caverject, Edex | MUSE |
| How it's given | A fine needle into the side of the shaft | A small pellet inserted into the urethra |
| Onset | 5–20 minutes | 5–10 minutes |
| Effectiveness | Higher | Lower than injection |
| Main drawback | Needle aversion; injection-site scarring over time | Penile and urethral burning; less reliable |
Risks
- Penile pain or aching — the most common complaint, reported by a substantial share of users
- Priapism — an erection lasting over 4 hours. The risk is higher than with oral medications and is a medical emergency
- Fibrosis or scarring at injection sites with long-term use, which is part of why technique and site rotation are taught
- Bleeding or bruising at the injection site
- Urethral burning with the suppository form
The cream Americans cannot get
There is a third delivery route for alprostadil that does not involve a needle or a suppository: a topical cream, marketed as Vitaros. It is applied to the tip of the penis using an absorption enhancer to carry the drug through the skin, and it works in roughly five to thirty minutes.
It is approved in Canada, Mexico, and much of Europe. It is not approved in the United States, and the reason is worth knowing.
So a genuinely useful middle option — alprostadil without the injection — exists in other countries and is unavailable here for commercial rather than clinical reasons. If you encounter a website offering to ship you Vitaros in the US, it is operating outside the approval system, with all the sourcing risks that implies. See how to buy ED medication online without getting scammed.
Where it sits in the treatment ladder
Clinical guidance generally puts oral PDE5 inhibitors first, then offers alprostadil, vacuum erection devices, or a penile prosthesis for people who do not respond or cannot take them. Alprostadil is a genuine option rather than a last resort — but the delivery method means most people reasonably try pills first.
One thing worth knowing if you are considering injections at all: alprostadil on its own is the FDA-approved option, but it is not the one most commonly prescribed. Trimix — a compounded blend of alprostadil with two other drugs — usually causes less penile aching, because it contains a much lower dose of the component responsible for it, and it typically costs far less per dose than single-use branded syringes. If injection therapy is on the table, ask about it specifically.
The non-drug alternative at the same rung is a vacuum erection device, which asks you to accept a pump rather than a needle. Below both sits a penile implant — the most effective option of all, and the only one that cannot be reversed.
Common questions
Does the injection hurt?
The needle itself is very fine and most people describe the stick as minor. The more common complaint is an aching sensation in the penis afterward, caused by the drug rather than the needle.
Can I use alprostadil if I take nitrates?
Alprostadil does not carry the nitrate interaction that PDE5 inhibitors do, which is one reason it's considered for people with cardiac disease. That said, it still requires medical evaluation, and sexual activity itself carries cardiac considerations worth discussing.
Is the suppository as effective as the injection?
No. The intraurethral form is generally less effective than injection, and many people who try it end up moving to injection if they need reliability.
Can alprostadil be combined with a PDE5 inhibitor?
Combination therapy is used in some cases, but only under direct medical supervision — combining vasodilators raises the risk of priapism and low blood pressure. Do not do this on your own.
Sources
- 1.Caverject (alprostadil) prescribing information — U.S. Food and Drug Administration
- 2.Erectile Dysfunction: AUA Guideline — American Urological Association