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| |  Viagra Offers Little Benefit To Women, Say Researchers NEW YORK, NY -- March 5, 1999 -- In the first evaluation of the effects of Pfizer Inc.’s Viagra(R) (sildenafil) on women, investigators at Columbia Presbyterian Center of New York Presbyterian Hospital found that, unlike in men, the drug offers little relief of sexual dysfunction. The results of the nonrandomised study, published in this month’s issue of Urology, examined the safety and efficacy of Viagra in 33 postmenopausal women with self-described sexual dysfunction of at least six months' duration. Each of the study participants took 50 mg of Viagra (the same dose prescribed for men) approximately one hour prior to planned sexual activity, but not more than once daily. All of the women were in stable, monogamous relationships with male partners that had begun at least six months earlier. Thirty women completed the study. The mean use of Viagra was about three times per week for the duration of the study. The most common symptoms of sexual dysfunction reported by the study participants included decreased arousal, decreased lubrication, diminished orgasm and inability to achieve orgasm. Therapy effectiveness was evaluated at four, eight and 12 weeks using a newly-developed nine-item self-administered Index of Female Sexual Function (IFSF). The IFSF uses a numbered scale (1 = almost never; 5 = almost always or always) to measure overall satisfaction with sexual function, orgasm, lubrication and clitoral sensation, as well as degree of lubrication and clitoral sensation and ability to achieve orgasm. In addition, women were asked to assess whether treatment improved overall sexual function. Blood pressure also was measured at each assessment visit and patients were questioned about any adverse reactions to Viagra. The IFSF is patterned after the International Index of Erectile Function (IIEF), a 15-question, validated, multidimensional, self-administered questionnaire that is used for assessing erectile dysfunction in men. Currently, there is no validated, widely accepted assessment tool for sexual function in women. "We found that there was no significant change either in intercourse satisfaction or in the degree of sexual desire after the patients had taken Viagra for 12 weeks," said Steven Kaplan, M.D., professor of urology at the Columbia University College of Physicians & Surgeons and the director of the Prostate Center at the Squier Urologic Clinic at the Columbia Presbyterian Center. Dr. Kaplan is also vice chairman and administrator of the department of urology and director of neurourology at the Columbia Presbyterian Center. "Even though about 25 percent of the patients had some improvement in overall sexual function, that's equal to the placebo response in men receiving Viagra. So that response might be a placebo effect rather than a true improvement in sexual function due to the drug, although that remains to be determined," Dr. Kaplan said. "Men and women have fairly equivalent placebo responses to other medications, so there is little reason to think that the placebo response rate would be different for Viagra." Overall, only 21 percent of patients had a significant (greater than 60 percent improvement in IFSF) response. Although the mean scores for the questions dealing with lubrication and clitoral sensation improved by 23 and 31 percent, respectively, those changes were not statistically significant. The mean score for the question regarding orgasm improved by only seven percent. Furthermore, the changes in overall scores for lubrication, clitoral sensation and orgasm were not significantly different for women who were on hormone replacement therapy versus those who were not. Only 20 percent of patients wished to continue drug therapy after 12 weeks. While the neurovascular events that accompany and result in erectile dysfunction in men have been well described, the corollary mechanisms in women have not. Unpublished preliminary data suggest that changes in both clitoral and vaginal blood flow are related to aging and may be involved with sexual dysfunction in women. "Viagra did appear to increase blood flow to the clitoris but this didn't seem to translate to increased sexual satisfaction," Dr. Kaplan said. "Neither increased clitoral sensation or lubrication would be expected to be of benefit to women with diminished desire to either initiate or respond to sexual activity." In fact, clitoral discomfort and hypersensitivity occurred in seven of the patients, three of whom withdrew from the study. Other side effects were minor (dizziness and headache) and did not cause withdrawal from the study. Dr. Kaplan cautions that while the Columbia Presbyterian Center study shows little to support the use of Viagra for postmenopausal women with sexual dysfunction, it must be noted that only a small number of women were evaluated and the follow-up was relatively short. In addition, the entry criteria were completely subjective. "Our study does, however, point out the need for a validated instrument to assess efficacy and sexual function in women, as there is for men," he said. “Larger, long-term studies in both post- and premenopausal women that look at different dosages and combinations with other drugs are necessary to fully assess Viagra's safety and efficacy regarding female sexual dysfunction." Related Links: Viagra, Pfizer Inc.
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