Women Don't Get a Rise Out of Taking Viagra

OB/GYN News, July 1, 2000 by Sherry Boschert

SAN FRANCISCO -- Viagra flopped in a randomized, double-blind, placebo-controlled study of 577 women with sexual dysfunction.

After 12 weeks of treatment, 40%-50% of patients reported improved sexual response regardless of whether they took placebo or 10, 50, or 100 mg of Viagra (sildenafil), Dr. Rosemary Basson said in a poster presentation at the annual meeting of the American College of Obstetricians and Gynecologists.

The multicenter study, which was conducted in Canada, Europe, and Australia, involved premenopausal and postmenopausal women who were taking hormone replacement therapy and had been diagnosed with female sexual arousal disorder, one of several categories that fall under the broad heading of sexual dysfunction, Dr. Basson explained.

Female sexual arousal disorder, however, was the primary presenting symptom in only 46% of the women, she said.

Twenty-eight percent of the patients reported hypoactive sexual desire disorder as the primary symptom, 17% of the women complained primarily of female orgasmic disorder, and 9% were troubled mainly by dyspareunia.

That broad spectrum of sexual complaints may have watered down the effectiveness of sildenafil compared with placebo, commented Dr. Basson of the departments of psychiatry and ob.gyn. at the University of British Columbia, Vancouver.

Only a small number of women with sexual dysfunction have poor genital response without any problems involving libido or mental arousal, yet those are the patients who are expected to be helped by sildenafil, she explained. Future trials will investigate whether there are subgroups of women with arousal disorder, such as those with difficulty getting extra blood to the vulvar and clitoral erectile tissue or to the front part of the vagina during sex.

Although genital blood flow increases in men and women during sex, its relevance to women is more questionable, Dr. Basson said.

"Men are directly conscious of it, whereas a woman is more likely to be indirectly conscious that genital touching doesn't feel so good" if blood flow doesn't increase, she said.

"Men come to the doctor and say, 'My penis doesn't work; it doesn't get erect.'

But women don't come in and say, 'This erectile tissue doesn't get swollen up,' " Dr. Basson said in an interview about the study

A 4-week treatment-free, run-in period preceded the 12 weeks of treatment with sildenafil or placebo. Patients had at least a 6-month history of sexual dysfunction at baseline.

Fifty-one patients participating in the study discontinued treatment due to side effects, which were mainly headache, flushing, rhinitis, nausea, abnormal vision, and dyspepsia.

One patient developed menorrhagia that was considered related to treatment.

Pfizer Inc., New York, the manufacturer of sildenafil, funded the study