Viagra, the famous sex-boosting drug, has grabbed headlines, imaginations and pocketbooks since its debut in April of 1998. Sales topped $1.2 billion in its first 12 months on the market. From April 1998 to August 1999, 13.5 million Viagra prescriptions have been filled, according to IMS Health, which tracks prescription drug consumption worldwide. Now researchers are questioning if Viagra benefits women, too.

More women than men experience sexual dysfunction -- 43 percent of women vs. 31 percent of men, according to a study in the Feb. 10, 1999 issue of the Journal of the American Medical Association. While the medical establishment is turning its attention to women and sexual dysfunction, just how beneficial the drug is for women remains unclear.

From the beginning, Pfizer, which manufactures Viagra, focused on male consumers after male test subjects taking the little blue pill for angina reported an odd side effect -- improved erections. However, Viagra increases blood flow not only to the penis, but also to the clitoris. So why does Pfizer target only men? "It was quite obvious that (treating men) was the first direction to go," says Maryann Caprino, a spokeswoman for Pfizer. "Female sexual dysfunction is far more difficult to measure and far less understood."

Despite Pfizer's "men first" approach, some doctors have prescribed it for female patients, although the drug is not yet approved by the Food and Drug Administration for such use. "Women respond great to Viagra. They actually do better then men," says Dr. H.G. Nurnberg, a professor at the University of New Mexico Health Sciences Center.

Nurnberg gave sildenafil, the active ingredient in Viagra, to a few women experiencing temporary antidepressant-induced sexual dysfunction. He later published his results in two journals. Viagra helped the women finish their course of medication while maintaining sexual function. However, a different study at Columbia University found that sildenafil is ineffective in women.

In an attempt to measure physiological responses rather than relying on self-reporting or questionnaires as previous studies had, Dr. Jennifer Berman, a urologist and co-director of Boston University's Women's Sexual Health Clinic, is working on two studies. "We have found that sildenafil significantly improves both subjective and objective parameters of the female sexual response," she says.

In Berman's study, she had women watch erotic movies and use a vibrator to stimulate themselves one hour after ingesting sildenafil. "We measure changes in blood flow, changes in genital sensation and changes in vaginal pH and vaginal elasticity," Berman says. However, "an increase in blood flow is meaningless unless the woman actually perceives enhanced sexual pleasure," she says.

Leonore Tiefer, clinical associate professor at Albert Einstein College of Medicine, states that idea more starkly. "There's no evidence that problems in blood flow to the clitoris contribute at all to women's (sexual dysfunction)," she says. Indeed, poor sexual knowledge, poor technique, uncooperative partners, poor self-image and inhibitions are well-documented causes of female sexual dysfunction, she says.

"There may be one woman in a thousand for whom (Viagra) is exactly right," says Tiefer. But "why is all the energy, all the attention, not to mention all the money, (focused) on one out of a thousand?"

The ideal candidates for Viagra appear to be women previously without problems who "because of menopause, hysterectomy or other pelvic injury are now not satisfied," says Laura Berman, Ph.D., a sex therapist, sister of Jennifer Berman, co-director of Boston University's Women's Sexual Health Clinic and co-researcher in the Boston University study. Emotional or relational reasons must be ruled out, she says.

Long-term effects of the drug are not known and current research is restricted to women who can't conceive or are using birth control. Deaths have occurred among people who have taken Viagra, and certain health conditions and medications are contraindicated with the drug.

Regardless of Viagra's effect on women, the question remains: Why has research with women and sexual dysfunction lagged so dramatically behind that of men?

"The field of medicine has been predominantly male," says Laura Berman. "For many decades, when a woman presented sexual complaints, a doctor would ask her if it hurt and if she was able to have sex." Beyond that, he did not pursue the matter. Questions about women's enjoyment, arousal levels and orgasms weren't addressed, she says.

Women with sexual problems don't have to wait until Viagra studies are completed. "There is a whole range of things that can help women," says Laura Berman. "Certainly, pharmacotherapy is not necessarily always the best and only option." In other words, all the answers don't reside in a little blue pill.