The antidepressant Lexapro appears to significantly cut the number and severity of hot flashes in menopausal women, researchers say, offering a potential new way to treat the symptom.

In a study testing the medication as a treatment for hot flashes, researchers found that women who experienced nearly 10 hot flashes a day at the start of the study saw those incidents drop to an average of just over five hot flashes a day after taking the antidepressant for eight weeks.

Those taking a placebo saw their hot flashes drop to 6.5 per day.

Hormone replacement therapy or HRT is the usual treatment for hot flashes. While it's effective, there are documented risks to taking HRT for prolonged periods. There are no other medications available to calm hot flashes, "and the efficacy of alternative pharmacologic and nonpharmacologic agents is inconclusive," the authors write as background in their article in JAMA, the Journal of the American Medical Association.

Selective serotonin and serotonin norepinephrine reuptake inhibitors (SSRIs and SNRIs) have been looked at as a treatment for hot flashes. So Dr. Ellen W. Freeman, of the University of Pennsylvania School of Medicine in Philadelphia decided to test one of them -- Lexapro -- in a randomized controlled trial.

They enrolled 205 healthy women: 95 African-American women; 102 white, and eight others. The women received 10 to 20 mg/d of escitalopram or a matching placebo for eight weeks. The women they kept daily diaries of the frequency and severity of their hot flashes.

The researchers found a 47 per cent decrease in hot flashes in the treated group, and a 33 per cent decrease in the placebo group. As well, escitalopram significantly reduced hot flash severity compared with the placebo, after adjusting for baseline severity and other factors.

"The three-week post-intervention follow-up demonstrated that hot flashes increased after cessation of escitalopram but not after cessation of placebo, providing further evidence of escitalopram's effects," the authors write.

Although the study looked only at Lexapro, other antidepressants including Paxil, fluoxetine, Prozac, and Effexor have also been found to be effective in other research.

The researchers note that although the decreases in hot flash frequency and severity appear modest, the study participants called the improvements meaningful, and most wanted to continue the treatment.

The study was funded by the U.S. National Institute on Aging.