Another form of treatment is an injection of a drug called Caverject or Viridal Duo (alprostadil) into the penis. This can be a successful treatment for ED in around seven out of ten men (70 per cent of men). The first time you use the drug, a nurse or doctor  will show you how to inject it into the base of the penis with a very fine needle. The drug causes the penis to fill with blood and you will get an erection within around 15 minutes. The erection will normally last for 30 to 40 minutes if the treatment has worked. The idea of an injection may sound alarming but the nurse or doctor will make sure you are confident giving the injection yourself in the clinic before you go home. You may also be able to use an injection pen which means you do not have to look at the needle. Generally this treatment does not cause significant side effects although many men do find that the injection is moderately painful. If you have any other problems, tell your specialist team. Occasionally the erection may persist beyond a comfortable length of time. This is called a priapism which is rare and affects less than one in 100 men (one per cent). If your erection lasts for over four hours some health professionals suggest putting a cold compress at the base of the penis. Alternatively, exercising to help you raise your heartbeat, for example running up and down stairs, may help your body to flush out the drug more quickly. If this does not work you should go to your local hospital accident and emergency (A&E) department for treatment.


The same drug alprostadil is also available as a small pellet, called MUSE. This is not as effective as using the injections but may be a good alternative if you do not like the idea of an injection. You use a disposable applicator to insert the pellet into the opening or ‘eye’ of the penis. You or your partner can then massage or stimulate your penis to melt the pellet and help the absorption of the drug. If the pellet works you should get an erection within five to 15 minutes, which will last between 30 and 60 minutes. MUSE may cause some pain in the penis or testicles and dizziness in some men. Injections or pellets can be used by men who have little or no sexual desire (libido), but they work better when you have some sexual interest and stimulation.