Q & A: Injection Therapy for Erectile Dysfunction (ED)
ED medicines that you take by mouth don’t work for everyone. In that case, men may be prescribed medicine that’s injected directly into the penis. Most men who find oral medicines to be ineffective respond to penile injection therapy. This is not a new treatment Penile injection therapy for ED was first introduced in the early 1980s, and has been used by hundreds of thousands of men.
How is Penile Injection Therapy done?
In penile injection therapy, the medication is injected directly into the inner part of the penis through a very small "insulin-style" needle. The medication is not injected under the skin, but must be injected into the inner part of the penis that fills with blood during an erection. A firm erection develops in 10-to-15 minutes and lasts 30-to-60 minutes.
Injection therapy typically uses one or more drugs which must be prescribed by a doctor, usually a urologist. When men are interested in penile injection therapy, the first trial injection is performed by the urologist in the office to be sure that the patient has no side effects. If a patient wishes to do injections at home he will come back for a second visit, during which the patient is taught how to do the injections. Patients can then try the injections at home.
What medicines are used for Penile Injection Therapy?
The most common medicines used for injection therapy are papavarine, phentolamine and alprostadil (also known as prostaglandin E.). This medication can be pre-mixed, in which case a man simply draws the right amount of medication into a syringe for injection. Patients who do not get an adequate erection with alprostadil, or who have pain after injection, may use a combination of papaverine, phentolamine, and alprostadil called tri-mix. This combination is prepared at specialty pharmacies and shipped to your home.
What are the risks of Penile Injection Therapy?
As with all medicine and medical procedures, there are some possible side effects. The biggest concern with using injection therapy is the possibility of developing prolonged erections (lasting longer than 4-6 hours). This is called “priapism” and can cause permanent damage to the erection tissue of the penis.
In general, minor side effects that may occur with penile injection therapy include:
- Mild bruising over the site of injection: this can be avoided by pressing over the injection site for 3 minutes (6 minutes if you are using a blood thinner)
- Penile pain: while uncommon, this occurs more often in men using injections that contain the medicine alprostadil. It is most common in men with diabetes and following radical prostatectomy surgery
- Swelling at the site of injection: this usually happens when some of the medication is discharged under the skin and usually occurs with poor technique