Injection Medications & Mechanism

1. It seems that there are several different medications suitable for injections. What are they and what are the trade offs?
2. How do these medications work to produce an erection?
3. Are there long term side effects to the use of injections? What are they?
4. Are there medical conditions that preclude the use of injections?

1. Q: It seems that there are several different medications suitable for injections. What are they and what are the trade offs?

   A: Each of these medications will work to help you achieve an erection. You should always consult your physician to discuss which is best for you. Some of the medicines currently in use include the following Papaverine--low cost and stable at room temperature but is less effective and may have a higher tendency to cause scarring (fibrosis). Papaverine plus phentolamine--more potent than papaverine alone but with the same potential side effects. Alprostadil--priapism is rare but pain is more common. (Alprostadil is also known prostaglandin or PGE-1, in powdered for it may be called Caverject or Edex.) Papaverine plus phentolamine plus Alprostadil--this is the most potent but requires refrigeration and has the same side effects as papaverine or phentolamine alone.

2. Q: How do these medications work to produce an erection?

   A: These drugs create an erection by relaxing the smooth muscles and widening the blood vessels in the penis. They are not dependant on nerve stimulation. (For a more complete discussion of how the penis functions see Lue, Thomas F.: A patient's Guide to Male Sexual Dysfunction.)

3. Q: Are there long term side effects to the use of injections? What are they?

   A: One possible side effect is development of curvature in the erect penis, which can be painful and interfere with intercourse. This is called Peyronie's Disease. It is caused by a buildup of plaque or scar tissue inside the penis in the lining of the corpora cavernosum. These are the two sponge-like cylinders running the length of the penis into which the medication is injected. It is relatively rare (about 3%) and can be treated. (You can minimize the risk by learning to inject correctly???this is not difficult.)

4. Q: Are there medical conditions that preclude the use of injections?

   A: Yes. 1. Severe scarring of the penis. 2. Allergic to any of the 3 medications. 3. Active infection or sore on the penis.