Prozac Shows Promise for Hot Flashes in Breast Cancer Survivors

From the WebMD Archives

Dec. 14, 1999 (San Antonio) -- Many women who defeat breast cancer may still have to deal with some of the side effects of the treatment. Now, researchers at the San Antonio Breast Cancer Symposium say Prozac may help beat one particularly uncomfortable effect -- hot flashes.

Oftentimes, methods used to treat breast cancer lower the amount of estrogen in a woman's system, and depending on the patient's age, force the body into early menopause, hence the hot flashes.

One solution is hormone therapy, in other words replacing the estrogen that was formerly deprived. But there is a risk with such therapy -- of aiding a recurrence of the breast cancer. Preliminary results from an ongoing clinical study show that treatment with the antidepressant Prozac (fluoxetine) can substantially reduce the incidence of hot flashes in breast cancer survivors who do not want to use hormone therapy.

More than of half the patients involved in the study say they have experienced at least a 50% decrease in hot flashes during 4 weeks of treatment with Prozac. When compared to placebo, there were no differences in toxic side effects, Charles Loprinzi, MD, tells WebMD. The findings, which he presented at the symposium, are consistent with other unpublished and anecdotal evidence suggesting that newer antidepressant agents can improve hot flashes.

But, Loprinzi, an oncologist at the Mayo Clinic in Rochester, Minn., says, "The definitive, statistically significant published data to confirm [the effectiveness] are pending." More patients are being added to the study to find out how well Prozac works for hot flashes and if there will be any harmful side effects.

The current findings are based on trials with only 33 patients, but they are consistent with findings from other studies. Clonidine, a medication used for high blood pressure, and vitamin E both have been shown to be superior to placebo for improving hot flashes, and megesterol acetate, used in hormone replacement, has been associated with a sizeable reduction of hot flashes after 4 weeks of treatment, Loprinzi said.

The trial involves breast cancer survivors who report at least two daily episodes of bothersome hot flashes for at least a month prior to enrollment. The patients take Prozac or a placebo daily for 4 weeks, and then switch to the opposite treatment for another 4 weeks.


Nearly half of the first group of patients reported 4-9 hot flash episodes at enrollment, and half reported 10 or more episodes daily. Two-thirds of the patients were aged 50 or older. During 4 weeks of treatment with Prozac, 53% of the women had hot flashes that were significantly lower in intensity. That compared with 19% of patients taking placebo.

Upon completion of the two four-week segments of the trial, patients rated their satisfaction with the two treatments. Loprinzi said twice as many patients chose the Prozac over the placebo. And, no differences in side effects were noted between the two options.

Similar to Prozac, investigation of the newer antidepressant Effexor (venlafaxine) has shown a reduction in hot flashes by half among women who took it.

At the symposium, Loprinzi offered what amounted to a preview of a trial being conducted by the National Comprehensive Cancer Treatment Group using Effexor, where preliminary findings aren't expected until spring. Still, Loprinzi says early findings show higher doses of Effexor were significantly more effective than placebo at limiting the amounts of hot flashes, often by half.

Loprinzi also pointed out that a report at the 1998 San Antonio meeting also showed favorable results with the antidepressant Paxil (paroxetine), which is similar to Prozac, for relief of hot flashes in breast cancer patients. Favorable results have been reported for other new generation antidepressants, including Zoloft (sertraline) and Wellbutrin (bupropion).

During a question-and-answer session at the San Antonio symposium, an unidentified physician in the audience said Paxil is associated with some risk of decreased libido, a side effect common to most drugs in its class of antidepressants. Representatives of breast cancer patient advocacy groups also expressed concern about the use of "powerful, potentially psychotropic (mind-altering) agents to treat hot flashes" when other options are available to breast cancer survivors, including natural therapies such as vitamin E and physical activity.

In response to the concerns, Loprinzi said, "These patients wanted to participate in this study because they had tried other therapies that hadn't worked. The hot flashes had become extremely bothersome to them, and they were willing to try something different. The patients were fully informed about the use of Prozac."

Among natural approaches to relieve hot flashes, soy currently generates the most enthusiasm, Loprinzi says.


Vital Information:

  • The antidepressant Prozac may be an effective treatment for breast cancer patients who are experiencing hot flashes.
  • Currently larger trials are underway to better define its effectiveness, as well as trials to research the effectiveness of other antidepressants in reducing hot flashes.
  • Some experts question the use of these medications to treat hot flashes, when other potential treatments are available, including vitamin E and physical activity.
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