Mainstay of treatment of ED were the methods which currently belong to the second line of therapy of erectile dysfunction before the effective oral medication PDE-5 inhibitors had became popular. First of all vasoactive intracavernous pharmacotherapy belongs to that line (papaverine, alprostadil or prostaglandin E1, and combinations as well). Now the only drug which is officially approved in Western Europe and the US is alprostadil. Alprostadil is sold under a brand name MUSE (Medicated Urethral System for Erection).
Much more rarely intraurethral injection of alprostadil is used in doses of 125 – 1000 mcg by using a “drug urethral system for erections” or MUSE. How does it work? Inserted into the urethra as a suppository, alprostadil due to vascular connections falls into cavernous body and causes dilation of its smooth muscles. To avoid discomfort during the procedure it is necessary to hold the penis horizontally with both hands and 10 minutes after it to seat or to stand. Usually during this time a man gets an erection that lasts 30-60 minutes. The most frequent complications of MUSE are pain in the urethra (29 – 41%), dizziness (1.9 – 14%) and 5% urethral bleeding. This system is contraindicated to use by men with penis curvatures and more than two times a day intermittently for at least 24 hours. We must not forget that the prostaglandins used for pregnancy termination, and this is a very important aspect.
MUSE, due to the low efficiency, high rate of complications and low compliance, currently is used mainly as an alternative to intracavernosal pharmacotherapy or in combination with PDE5 inhibitors. It can be used by patients who have removed for some reason prosthesis and re-implantation has not been performed. To use this system can be dangerous if you have:
– circulatory disorders or nerve damages;
– bleeding caused by taking medications that thin the blood such as heparin or warfarin;
Alprostadil is produced from prostaglandin E1 which significantly increases the size of the blood vessels.
Currently, such combinations are recommended for using: prostaglandin E1 with Prazosin or with sildenafil.