Mayo Clinic: Men’s Health Center


You use a fine needle to inject the medication alprostadil (Caverject Impulse, Edex) into the base or side of your penis. In some cases, medications generally used for other conditions are used for penile injections on their own or in combination. Examples include papaverine, alprostadil and phentolamine. Often these combination medications are known as bimix (if two medications are included) or trimix (if three are included).

Each injection is dosed to create an erection lasting no longer than an hour. Because the needle used is very fine, pain from the injection site is usually minor.

During the procedure

A nurse injects medicine into the side of the penis. This can cause minor pain, typically rated 0-3 on a scale of 0-10, where 0 is no pain and 10 is very severe pain. It’s important to pay attention to the penile injection process, the pain experienced and the quality of the erection to help determine if penile injections could be used as a potential long term solution for ED for you. Over the next several minutes, you’re left alone as the medication takes effect. The goal is to achieve an erection as good as or better than one you could obtain at home. Penile injections may be repeated if the erection isn’t strong enough.

After the procedure

You should be able to return to normal activities immediately after the erection subsides. You’re not allowed to leave the clinic until this occurs.


Side effects can include mild bleeding from the injection, prolonged erection (priapism) and, rarely, formation of fibrous tissue at the injection site. If priapism occurs, several doses of an erection antidote (phenylephrine) may be injected into the penis. If this fails, a minor office procedure may need to be performed to help resolve the erection.

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