The new medication, called Pristiq, is under review by the FDA, according to the manufacturer, Wyeth Pharmaceuticals.
"Pristiq is going to fill a needed void," says David Archer, M.D., professor of obstetrics and gynecology at Eastern Virginia Medical School in Norfolk.
He's referring to the void left when legions of women gave up hormone replacement therapy after a federally funded trial in 2002 showed that long-term hormone therapy boosts risks of heart attack, breast cancer, and other problems. Archer led clinical trials of Pristiq and has worked as a consultant for Wyeth.
But another expert not involved in the research cautions that the studies are preliminary and the exact role the new medication will have in relief of menopausal symptoms is yet to be determined.
Researchers presented the studies at the 55th Annual Clinical Meeting of the American College of Obstetricians and Gynecologists in San Diego.
Pristiq is a modified version of Wyeth's antidepressant Effexor, Archer says. Effexor and Pristiq belong to a class of drugs known as serotonin/norepinephrine reuptake inhibitors, or SNRIs.
When a woman is going through menopause, fluctuations in estrogen may diminish both brain chemicals serotonin and norepinephrine, according to Wyeth. Pristiq is thought to work by making more of both substances available, improving mood and menopausal symptoms in the process.
In five studies presented Tuesday and Wednesday at the meeting, Pristiq was evaluated for its value in relieving hot flashes and night sweats, reducing nighttime awakenings from night sweats, and improving mood. Because sexual problems have been associated with the use of some antidepressants, another study looked at whether Pristiq affected women's sex lives.
The results were mixed:
In a 12-month study of the drug, women who had 50 or more moderate to severe hot flashes weekly were assigned to placebo or Pristiq (50, 100, 150, or 200 milligrams), says Margery Gass, M.D., professor of obstetrics and gynecology at the University of Cincinnati and an author of the study. She found a 60 percent to 64 percent reduction in the hot flashes as well as fewer nighttime awakenings due to night sweats. "Overall, the 100-milligram dose worked best," she tells WebMD.
But in another study of 465 women, conducted by James Pickar, M.D., of Wyeth, Pristiq did not work much better than placebo and was inferior to tibolone, a hot-flash-relieving drug not available in the United States. At week 12, placebo reduced hot flashes by 57.5 percent, Pristiq by 57.7 percent, and tibolone by 81 percent.
"I think these are preliminary studies," says William Parker, M.D., staff gynecologist at Santa Monica-UCLA and Orthopaedic Hospital in Santa Monica, Calif. "I'd like to see a head-to-head comparison study with SSRIs." Many doctors prescribe the SSRI antidepressants to help relieve hot flashes and other symptoms of menopause.
Parker points out, too, that nausea is one of the side effects reported with Pristiq use. Researchers say the nausea subsides. According to Wyeth spokeswoman Danielle Halstrom, a new technique of increasing the dose over three days is expected to remedy the nausea problem.
Parker, like many other gynecologists, still prescribes hormone replacement therapy for some women for short periods of time, if they determine the benefits outweigh the risks, while reassessing their needs often.
"Hormone therapy is probably still the best for hot flashes," Archer concedes. But Pristiq, when approved, will simply give women another option, he says.
By Kathleen Doheny
Reviewed by Louise Chang, M.D.
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