Safety and efficacy of a testosterone metered-dose transdermal spray for treating decreased sexual satisfaction in premenopausal women

Background: it is not known whether premenopausal women who report low sexual satisfaction and have low circulating testosterone levels will benefit from testosterone therapy. Objective: To evaluate the effects of exogenous testosterone in premenopausal women reporting diminished sexual function. Design: Randomized, double-blind, placebo-controlled, close-ranging trial. Setting: 6 Australian medical centers. Patients: 261 women age 35 to 46 years who reported a decrease in satisfying sexual activity relative to their younger years and had a morning serum free testosterone level less than 3.8 pmol/L (<1.1 pg/mL). Intervention: 3 different doses of testosterone administered by a metered-dose transdermal spray for 16 weeks or placebo. Measurements: The primary outcome was the mean number of self-reported satisfactory sexual events (SSEs) over 28 days at week 16. The frequency of SSEs, total number of sexual events (every 4 weeks), scores from the modified Sabbatsberg Sexual Self-Rating Scale and the Psychological General Well-Being Index, and safety variables were also measured. Results: The number of SSEs increased during the treatment period in the active treatment groups and the placebo group. The mean number of SSEs over 28 days at week 16 was statistically significantly greater for women treated with the intermediate dose of testosterone therapy (one 90-mu L spray) than for women treated with placebo. The least-squares mean was 2.48 versus 1.70 SSEs, respectively (event rate ratio, 1.49 [95% CI, 1.01 to 2.18]; P = 0.04). The frequency of SSEs in women treated with low and high doses of testosterone did not differ from that in women who took placebo. The rate ratios based on the least-squares mean rates of SSEs during weeks 4 to 16 for each treatment group showed statistically significant or borderline significant increases in all testosterone groups compared with the placebo group. The rate ratios for the one 56-mu L spray, one 90-mu L spray, and two 90-mu L sprays treatment groups were 1.34 (CI, 0.97 to 1.85; P = 0.081), 1.48 (CI, 1.07 to 2.06; P = 0.018), and 1.38 (CI, 1.00 to 1.92; P = 0.052), respectively. At week 16, 95% of women treated with the one 90-mu L dose had a free testosterone level less than the upper limit of the reference range for women. The most frequently reported adverse event was hypertrichosis, which was dose-related and mostly confined to the application site. No clinically relevant changes in blood test values, serum biochemical variables, or vital signs occurred. Limitation: The study duration was short, and the placebo effect was strong. Conclusion: A daily 90-mu L dose of transdermal testosterone improves self-reported sexual satisfaction for premenopausal women with reduced libido and low serum-free testosterone levels by a mean of 0.8 SSE per month. The rate of SSEs with higher and lower testosterone doses did not differ from that with placebo.