Brand Name: AndroGel
Active Ingredient: testosterone
Indication: Topical testosterone replacement for men with low testosterone
Company Name: Unimed Pharmaceuticals, Inc.
Availability: Approved by FDA February 28, 2000
Introduction
An estimated 4 to 5 million men experience the effects of low testosterone – also known as hypogonadism – including a diminished interest in sex, impotence, reduced lean body mass, decreased bone density, and low mood and energy levels. Testosterone replacement has most commonly been achieved using painful deep muscle injections and potentially irritating transdermal patches.
A new form of testosterone replacement will soon be available in the US in the form of a gel: AndroGel 1%. Manufactured by Unimed Pharmaceuticals, Inc., a subsidiary of Solvay Pharmaceuticals, Inc., AndroGel was approved by the FDA on February 28, 2000, and is expected to be available with a prescription in the US by mid-summer. AndroGel is a clear colorless gel that men apply once daily to their shoulders, upper arms, and/or abdomen. The gel dries within a few minutes of application.
How It Works
Upon application to the skin, AndroGel is absorbed through the skin, which serves as a reservoir for the hormone. The testosterone slowly enters the circulation, and normal testosterone levels (298-1043 ng/dl) are restored within a few hours. Absorption of testosterone into the blood continues for the entire 24-hour dosing interval.
AndroGel: Clinical Study Results
The results of a clinical study demonstrating the efficacy of AndroGel will be presented at the 82nd Annual Meeting of the Endocrine Society in June 2000 in Toronto. AndroGel 1% was evaluated in a multicenter, randomized, parallel-group, active-controlled, 180-day trial in 227 hypogonadal men. The study was conducted in 2 phases. During the initial treatment period (days 1-90), 73 patients were randomized to AndroGel 5 G daily (to deliver 50 mg testosterone), 78 patients to AndroGel 10 G daily (to deliver 100 mg testosterone), and 76 patients to a non-scrotal testosterone transdermal system (5 mg daily). The study was double-blind for dose of AndroGel but open-label for active control. Patients who were originally randomized to AndroGel and who had single-sample serum testosterone levels above or below the normal range on day 60 were titrated to 7.5 G daily (to deliver 75 mg testosterone) on day 91. During the extended treatment period (days 91-180), 51 patients continued on AndroGel 5 G daily, 52 patients continued on AndroGel 10 G daily, 41 patients continued on a non-scrotal testosterone transdermal system (5 mg daily), and 40 patients received AndroGel 7.5 G daily.
Mean peak, trough, and average serum testosterone concentrations within the normal range (298-1043 ng/dl) were achieved on the first day of treatment with doses of 5 G and 10 G. In patients continuing on AndroGel 5 G and 10 G, these mean testosterone levels were maintained within the normal range for the 180-day duration of the study. Testosterone concentrations were maintained as long as the patient continued to apply the prescribed AndroGel treatment properly. On treatment day 180, the 7.5 G dose was found to produce mean concentrations intermediate to those produced by 5 G and 10 G of AndroGel. Of 129 hypogonadal men who were appropriately titrated with AndroGel and who had sufficient data for analysis, 87% achieved an average serum testosterone level within the normal range on treatment day 180.
AndroGel 5 G/day and 10 G/day resulted in significant increases over time in total body mass and total body lean mass, while total body fat mass and the percent body fat decreased significantly. These changes were maintained for 180 days of treatment. Changes in the 7.5 G dose group were similar. Bone mineral density in both hip and spine increased significantly from baseline to day 180 with 10 G AndroGel.
AndroGel treatment at 5 G/day and 10 G/day for 90 days produced significant improvement in libido (measured by sexual motivation, sexual activity, and enjoyment of sexual activity as assessed by patient responses to a questionnaire). The degree of penile erection, as subjectively estimated by the patients, increased with AndroGel treatment, as did the subjective score for “satisfactory duration of erection.” AndroGel treatment at 5 G/day and 10 G/day produced positive effects on mood and fatigue. Similar changes were seen after 180 days of treatment and in the group treated with the 7.5 G dose.
What the Patient Should Know
The most commonly reported side effects associated with AndroGel were acne and a skin reaction at the application site. Seven patients experienced a prostate disorder, most often enlargement of the prostate. Nine patients had abnormal lab test results.
After applying AndroGel, men should avoid bathing or showering for at least 5-6 hours. AndroGel should not be applied to the scrotum.
AndroGel is contraindicated in men with breast or prostate cancer. Geriatric patients may be at risk for prostatic hyperplasia and cancer.
Vigorous skin-to-skin contact may transfer testosterone from the treated individual to an untreated individual and increase serum testosterone levels in the untreated person. This can be prevented if the treated individual wears a shirt after applying AndroGel. Residual testosterone can be removed from the skin with soap and water.
AndroGel is not indicated for use in women. Pregnant women should avoid skin contact with AndroGel application sites in men, since testosterone may harm the fetus.
Jennifer is a clinical pharmacologist. She helps doctors of all medical specialties choose medications. Jennifer consults about drug dosage, interactions, and side effects.