This information is for men who have erection problems. It tells you about alprostadil pellets, a treatment used for erection problems. It is based on the best and most up-to-date research.
Do they work?
Yes. If you have erection problems, a drug called alprostadil may help you get or keep an erection. You can take this drug as pellets that you put up your urethra (the tube in your penis that carries urine and semen).
In studies, between 6 and 7 out of 10 men who used alprostadil pellets found that they worked.
Alprostadil pellets don't work as well as alprostadil injections. We don't know if they work as well as other erection drugs that you take as tablets. But you may decide to use pellets if you don't want to have injections or take erection drugs, or if these other treatments haven't worked.
What are they?
Alprostadil is a drug that widens the blood vessels in your penis so that more blood flows through. This makes your penis firmer.
Alprostadil pellets are tiny tablets that you put into your urethra using a special device:
The device has a thin stem that you push into your urethra
You push a button at the top of the device that pushes out the pellet of medicine
The medicine goes straight to the part of your penis that becomes stiff during an erection.
The brand name for alprostadil pellets is Muse. You may hear doctors call it intraurethral alprostadil.
You can also take alprostadil as an injection.
Alprostadil isn't available to everyone on the NHS. For more, see Treatment for erection problems on the NHS.
How can they help?
Alprostadil pellets can help by: 
Giving you an erection that is firm enough to have sex
Making sex more enjoyable for you and your partner
Making you feel better about your relationship.
Alprostadil pellets work for between 6 and 7 out of 10 men who try them.
Alprostadil pellets can also help you get erections if you've had surgery to remove your prostate gland (an operation called a prostatectomy). More than half the men studied were helped. 
But pellets don't work as well as taking alprostadil as an injection.    In one study, 9 in 10 men who had alprostadil injections were able to have sex compared with 6 in 10 men who used alprostadil pellets. 
How do they work?
Alprostadil pellets have a chemical called prostaglandin E1 (or PGE1 for short). This is like a chemical made naturally by your body. It makes blood vessels open wider so that more blood can flow through.
When you put a pellet into your penis, the chemicals can easily get to the blood vessels in your penis. These blood vessels get wider and more blood flows into your penis, making it firmer. Getting a firmer penis helps you get a better erection.