FDA Approves Gel to Treat Low Testosterone Levels
March 2, 2000 (Atlanta) -- The FDA this week approved the first testosterone gel for treatment of men with low testosterone levels. The gel, called AndroGel, is applied once daily to the shoulders, upper arm, and/or abdomen.
"This is a quite convenient way of delivering testosterone in a dose-related fashion. The more you put on, the higher the testosterone," Ronald S. Swerdloff, MD, tells WebMD. Swerdloff is chief and professor of medicine, division of endocrinology, at Harbor-UCLA Medical Center in Los Angeles. He was the lead investigator of AndroGel on behalf of the manufacturer, Unimed Pharmaceuticals Inc.
"The testosterone gel has several advantages over the [currently] available delivery systems," Swerdloff says. Unlike injections, the gel does not cause discomfort, and it provides a constant level of testosterone. The oral versions of testosterone are synthetic and may be damaging to the liver, while transdermal patches often have problems with adhesiveness.
Testosterone, one of a class of hormones known as androgens, is responsible for the development of the male sex organs and for the maintenance of secondary sex characteristics, including development of facial and pubic hair, vocal cord thickening, and alterations of body musculature. Low testosterone, a condition called hypogonadism, affects approximately 4-5 million American men and is linked to diminished interest in sex, impotence, reduced lean body mass, decreased bone density, and lowered mood and energy levels.
AndroGel is a colorless gel containing 1% testosterone. It is applied daily to clean, dry skin; the gel dries within a few minutes and is absorbed into the skin, which serves as a reservoir, providing sustained delivery to the bloodstream for up to 24 hours. After applying the gel, patients should immediately wash their hands to avoid exposing others to the medication. The gel should not be used on women, and pregnant women should avoid contact with the application sites of the gel on men, as it could harm the fetus.
In the female partners of men using AndroGel, 15 minutes of vigorous skin-to-skin contact increased testosterone in the women to twice their ordinary levels. When a shirt was worn to cover the gel-application site, transfer of testosterone to the women was prevented.