This is a highly effective treatment option when oral therapy fails. Patients are taught to inject into the side of their penis directly into the corpus cavernosum (the corpus cavernosa are two long cylinders in the penis which sit side by side and run the length of the penis). The most commonly used substance is alprostadil but it can also be used in combination with paparevine or phentolamine or even with both. After the injection, an erection occurs within 5 to 15 minutes, automatically without stimulation, and lasts 30 – 40 minutes depending on the dose used. If injections don’t work it is usually an indication that there is severe damage to the blood vessels in the penis and the last resort is then surgery.

Side effects of injection treatments for ED
Injection treatments into the penis can cause priapism. This is a prolonged, painful erection which lasts for more than 4 hours and it is an extremely dangerous condition. Priapism is a medical emergency that requires urgent treatment by a medical doctor. If priapism is not treated within 4 to 6 hours there may be permanent irreversible damage.

Other side effects of injection treatment include:
– A burning sensation
– Bleeding
– Pain
– Swelling
– Permanent scarring in the penile tissue due to needle damage

References:
Smart D. The SASHA Guide to Erections and Erection Problems. © Ronin-Do (Pty) Ltd 2004.
Lissoos I. Know your manhood. KYB Pocket Books 1984.
Hackett G et al. British Society for Sexual Medicine Guidelines on the Management of Erectile Dysfunction. J Sex Med 2008; 5:1841–1865