Cross-Gender Sex Pill

By Arnold Mann

Irwin Goldstein could hardly wait for the FDA to approve Viagra. The renowned Boston University urologist is so excited about last week's approval of the first-ever impotence pill for men that he is opening a new sexual-dysfunction clinic, and will soon begin prescribing the drug--for women.

As doctors learn more about the causes of impotence, they're becoming increasingly convinced that the underlying mechanisms of male and female sexual dysfunction may not be so far apart. And if that's the case, it's entirely possible that the same pharmacological science that restores sexual function to men can work similar magic in women.

Viagra trials in women are already under way in Europe. In April the FDA is holding an invitation-only meeting of scientists and pharmaceutical executives to discuss possible testing and use of the drug in women in the U.S. And in June leading sex researchers will devote their annual meeting in Cape Cod to discussing how a range of impotence drugs might be tested in female patients. If the medications prove effective, they could offer women a safer alternative to the current best weapon against female sexual dysfunction, hormone-replacement therapy, which carries a slightly increased risk of cancer. Meanwhile, with the approval of Viagra (release date: mid-April) as an impotence treatment, doctors will be able to prescribe it "off-label" for women too. "We intend to use it in women once it's released for men," Goldstein says. "Not even a question."

Viagra's effects on the hydraulics of male sexuality are pretty straightforward. Originally developed as a heart medication, the drug works directly on the blood vessels, blocking an enzyme called phosphodiesterase. This enzyme prevents the release of certain neurotransmitters--most notably one called cyclic GMP--that cause the smooth muscles surrounding arteries to relax, allowing the arteries to expand. When this occurs in penile arteries, it leads to engorgement, which leads to erection.

While Viagra doesn't work for every impotent man, it does work for up to 80% of them. "There appears to be no group that has been tested that has a zero response," says urologist Dr. Harin Padma-Nathan of the University of Southern California. Even men with the most severe forms of impotence--spinal-injury victims, diabetics, those who have undergone prostate-cancer surgery--have responded.

Such results ought to mean good things for women too. Female genitals fill with blood during sexual stimulation just as male genitals do, resulting in engorgement of the clitoris and lubrication of the vagina. As women age, they experience some of the same genital problems men do, as a number of ailments--particularly atherosclerosis and diabetes--impair blood flow; this leads to vaginal dryness, pain during intercourse and problems in achieving orgasm. Indeed, according to one study, more than a third of women in the 18-to-59 age group experience sexual dysfunction, compared with just 10% of men. "Male sexuality has always been viewed as more important," says Julia Heiman, a psychologist at the University of Washington and one of the nation's leading experts on female sexual dysfunction. "A man needs an erection to have intercourse, so it's easy to regard a man's sexuality as important and a woman's as sort of an interesting pastime."

How effective Viagra is in women awaits the outcome of the tests. The FDA and Pfizer, the manufacturer, do not encourage women to use it. "We strongly recommend against women taking their husband's pills or physicians using it off-label," says Raymond Rosen, professor of psychiatry at the Robert Wood Johnson Medical School in New Jersey, who will chair the Cape Cod meeting.

Still, when it comes to Viagra, some physicians see potential benefits in careful, off-label use. Goldstein plans to test female patients--mostly postmenopausal women--for impaired blood flow and give the drug to those he thinks it can help. He has already received E-mail from women eager to try it. Other doctors are bracing for the same. "The Viagra avalanche is about to begin," says Rosen. "Where the oral contraceptive was liberating for younger people, Viagra may be the sexual-liberation pill of older adults." This time both men and women will be getting in line.