Premenopausal women treated for breast cancer often undergo premature menopause from chemotherapy, and hot flashes are a common side effect of tamoxifen, which is often given to prevent recurrence in breast cancer survivors. Many doctors are reluctant to prescribe hormones such as estrogen or progesterone -- known to reduce hot flashes -- for women with a history of breast cancer for fear it might stimulate a recurrence of the disease.

"This research is a small step in the right direction," says Herman Kattlove, MD, Medical Editor for the American Cancer Society. "Hot flashes are a terrible problem for some women, and it's important we begin to find ways to help using non-hormonal treatment."

The Lancet study descibes a four-week, randomized, controlled trial of 191 women with a history of breast cancer who were concerned about taking hormones. All of the women had experienced hot flashes at least 14 times per week severe enough for them to desire therapeutic intervention. The women were given either a placebo or one of three different doses of venlafaxine.

All the particiapnts experienced a reduction in the number and severity of hot flashes. The placebo group reported a 27% reduction; the group taking 37.5mg venlafaxine reported a 37% reduction; and the 75mg and 150mg groups each reported a 61% reduction. Side effects including dry mouth, decreased appetite, nausea, and constipation were significantly higher in the 75mg and 150mg venlafaxine groups than for those taking the placebo or the lower dose of the medication. An unsought finding of the study showed that, over the four-week period, libido improved for the women taking venlafaxine.

The trial suggests that venlafaxine can alleviate hot flashes and that the most appropriate dose for this symptom is 75mg daily, which was more effective than the lower dose but had fewer side effects and was as therapeutic as the 150mg dose. Venlafaxine reduced hot flashes within days, rather than weeks, as is generally the case with hormone treatments. Other studies have found it reduced hot flashes in men who have undergone androgen deprivation therapy for prostate cancer.

Preliminary results from other studies suggest that other new antidepressants, such as Paxil, might also alleviate hot flashes. According to Charles Loprinzi, MD, Principal Author of the study and professor and chair of medical oncology at the Mayo Clinic, the next step for researchers is "to begin looking at other medications in this class of new antidepressants to see which work, at what dose, and with the least side effects. We also need to compare the results of non-hormone treatment of hot flashes to progestagens -- that is, progesterone-type drugs."

How long women may safely take antidepressants for hot flashes is another question for future research. "Hot flashes may go on for weeks, months, or years," says Loprinzi. "It's a completely individual process."