Cold water on female Viagra?
By Marie McCullough
Inquirer Staff Writer
A new study has found that the quality of women's lives in the bedroom has nothing to do with the amount of testosterone in their blood.
This might seem to be bad news for the score of drug companies developing testosterone products in hopes of tapping the estimated $1 billion market for a female counterpart to Viagra.
"Our study is going to frustrate a lot of doctors," said lead author Susan Davis, an endocrinologist at Monash Medical School in Australia. Treating female sexual complaints "is not just about giving testosterone. It's far, far more complicated."
But the researchers who conducted the study are not counting testosterone out. While levels in the blood may not be meaningful, levels in the brain, bone and fat - where the hormone cannot be measured - may affect the female libido.
"Our results," they concluded, "are not in conflict with testosterone being used... to treat hypoactive sexual desire disorder" - the new term for women affected by low libido.
The results do not support testosterone being used, either, Davis said from Victoria, Australia.
The study, in today's Journal of the American Medical Association, is sure to fuel controversy on the safety and science behind female testosterone supplements - before a single one is approved.
In December, advisers to the Food and Drug Administration unanimously voted that Procter & Gamble had not proved the safety of its experimental testosterone patch, Intrinsa. A majority also judged Intrinsa's effectiveness to be unproven in studies, since a placebo also perked up menopausal women's sex lives.
Procter & Gamble is still seeking to market the patch in this country, Europe and Canada, company officials said yesterday.
As for the Australian findings, P&G physician Kathryn Wekselman said hormone levels did not always correlate with symptoms.
"If you look at estrogen levels, you cannot predict which menopausal women will have hot flashes," she said. "So if that [disconnect] was the same with testosterone, it would not be unprecedented."
Unpredictable results
But while estrogen clearly works for hot flashes, testosterone is unpredictable for women with lagging libidos. In Intrinsa studies in postmenopausal women, patch users had on average one more "satisfying sexual" episode per month, over six months than women on a placebo; in a second study, the patch made even less difference.
Still, doctors have for decades prescribed testosterone creams and pills to improve female sex drive, particularly after a hysterectomy. The FDA permits such "off-label" treatment.
The Australian study involved 1,021 women aged 18 to 75 who completed a questionnaire on sexual well-being developed by Procter & Gamble. (Although P&G did not fund the study, Davis has worked on the Intrinsa research.)
The researchers measured their blood levels of testosterone as well as DHEA sulphate, a hormone produced by the adrenal glands that is converted to estrogen and testosterone.
A different approach?
While the testosterone level was irrelevant to the women's reported arousal, desire, orgasm and self-image, low levels of DHEA sulphate did correlate with sexual problems in women under 45 and, to a lesser degree, in women over 45.
Still, researchers could not say DHEA therapy is a good idea, anymore than they could say testosterone therapy is a bad idea.
New York City psychiatrist Lenore Tiefer, a critic of the push for testosterone treatment, found that conclusion illogical.
"The one thing that does emerge is that DHEA may be useful," Tiefer said. "But DHEA is an over-the-counter dietary supplement, so there's no money in it."
Tiefer speculated that since testosterone was relatively difficult and expensive to measure in the blood, drug companies may welcome the new evidence that measuring it is pointless.
"The companies are going to spin this to say, 'Now we have proof that you don't need to measure testosterone,' " Tiefer said. "The companies want women to go directly from having subjective [sexual] distress to getting the product - no diagnosis, no workup