A prostaglandin for erectile dysfunction
Alprostadil
A prostaglandin used as an injection, urethral pellet or cream to produce an erection when tablets do not work.
What is Alprostadil?
Alprostadil is a prostaglandin medicine used to treat erectile dysfunction (difficulty getting or keeping an erection), usually when tablets such as sildenafil have not worked or are not suitable. Unlike tablets, it is applied directly to the penis: as an injection into the side of the penis, a small pellet placed into the tip of the penis (MUSE), or a cream put into the opening at the tip (Vitaros). It widens blood vessels so blood flows in and an erection follows, often within minutes. It is important to seek urgent medical help if an erection lasts too long (priapism), as this can damage the penis.
Education and reference only. This is a plain-language guide to Alprostadil — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Alprostadil is a man-made version of a natural body chemical called a prostaglandin. It is used to treat erectile dysfunction, the inability to get or keep an erection firm enough for sex, particularly when tablets have not helped or cannot be used. Rather than being swallowed, it is delivered straight to the penis in one of three ways: as an injection into the side of the shaft (brands such as Caverject and Viridal), as a tiny pellet inserted into the tube at the tip of the penis (MUSE), or as a cream applied to the opening at the tip (Vitaros). It produces an erection by improving blood flow into the penis.
How it works
Alprostadil relaxes and widens the blood vessels and muscle inside the penis. This lets more blood flow in and become trapped, producing an erection, usually within several minutes of using it. Because it works directly on the blood vessels in the penis rather than relying on nerve signals or sexual stimulation in the way tablets do, it can work for men in whom tablets have failed. The erection it produces should fade after intercourse; if it lasts too long, this needs urgent treatment.
Company & origin
Originated / developed by: Various (Pfizer, others).
A prostaglandin medicine used in the UK to produce an erection in men with erectile dysfunction, usually when tablets have not worked.
What it treats
Conditions Alprostadil is used for
Practical use
How to take Alprostadil
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Use exactly the method and amount you were shown for your brand, whether injection, pellet (MUSE) or cream (Vitaros).
- For the injection, follow the training you were given on technique and on rotating the site, and never use more than your agreed amount.
- Do not use it more often than advised, and leave the recommended gap between uses.
- Seek urgent medical help if your erection lasts too long or becomes painful, as this can damage the penis.
- Store it as directed and keep it, and any needles, well out of the reach of children.
Weighing it up
Advantages & disadvantages of Alprostadil
Advantages
- Can produce an erection in men for whom tablets have not worked or are unsuitable.
- Works fairly quickly, often within minutes, acting directly on the penis.
- Comes in different forms (injection, urethral pellet or cream) to suit different preferences.
Disadvantages
- Must be injected into, or applied directly to, the penis rather than taken as a tablet.
- Can cause pain or aching in the penis, particularly with the injection or pellet.
- Carries a risk of a prolonged, painful erection (priapism) that needs urgent treatment.
Practical use
Good to know
The most important safety point is priapism: an erection that lasts too long (often described as several hours) is a medical emergency, because a prolonged erection can starve the penis of oxygen and cause lasting damage, so you should seek urgent medical help rather than waiting. With the injection, a healthcare professional will teach you the correct technique and the lowest amount that works for you, to reduce the risk of a long-lasting or painful erection. Some men get aching or pain in the penis, particularly with the injection or pellet. It should not be used more often than advised, and not by men for whom an erection is medically inadvisable. It is for the man being treated and should not be shared; the urethral pellet and cream can also affect a partner, so a condom may be advised in some situations such as pregnancy.
Who should not take it / use with caution
- Men in whom sexual activity is inadvisable, or who have certain conditions that predispose to a prolonged erection (such as sickle cell disease or some blood cancers), should not use it.
- It should not be used by men with a penile implant or with certain anatomical problems of the penis, unless a specialist advises.
- It is for the man being treated and should not be shared with anyone else.
Monitoring
- Teaching and checking correct technique, and finding the lowest amount that works for you.
- Reviewing how well it works and whether you get pain or other side effects.
- Making sure you know to seek urgent help for an erection that lasts too long.
Side effects
- Pain or aching in the penis is common, especially with the injection or pellet.
- Redness, mild bleeding or bruising at an injection site, or a burning feeling with the pellet or cream.
- A prolonged or painful erection (priapism) is uncommon but serious and needs urgent help.
Key interactions
- Other medicines for erectile problems, such as sildenafil, should not be combined with it without specialist advice.
- Blood-thinning medicines can increase bruising or bleeding at an injection site.
- Medicines that lower blood pressure may add to any drop in blood pressure or dizziness.
Available as: Solution for injection into the penis, a urethral pellet (MUSE) and a cream applied to the tip of the penis (Vitaros).
Answers
Alprostadil: frequently asked questions
How is alprostadil used?
Depending on the brand, it is injected into the side of the penis, inserted as a small pellet into the tip of the penis (MUSE), or applied as a cream to the opening at the tip (Vitaros).
When is it used instead of tablets?
It is usually used when tablets such as sildenafil have not worked or are not suitable, as it acts directly on the penis.
What should I do if my erection won't go down?
An erection that lasts too long is a medical emergency. Seek urgent medical help straight away, as a prolonged erection can damage the penis.
Does it hurt?
Some men get aching or pain in the penis, particularly with the injection or pellet; a healthcare professional will help you find the form and amount that suits you best.
Can it affect my partner?
The urethral pellet and cream can pass to a partner, so a condom may be advised in some situations, such as if your partner is or could become pregnant.
Authoritative sources
- BNF
- NICE CKS
Building a medicines information resource?
We create evidence-led, dose-free drug and formulary references for teams.