(The New York Times News Service) -- Hot flashes, including sweating, palpitations and anxiety, are common side effects in women receiving chemotherapy or hormone therapy for breast cancer.

Now, researchers say the epilepsy drug gabapentin, sold as Neurontin, can reduce hot flashes by 46 percent in women fighting the disease.

"Women who have breast cancer and need to take drugs like tamoxifen and other drugs that are potentially likely to cause hot flashes can benefit from gabapentin," says lead researcher Dr.

Kishan J. Pandya, a professor of medicine at the University of Rochester Cancer Center.

His team's findings appear in the Sept. 3 issue of The Lancet.

Hormone supplements of estrogen and progestagen are the usual treatment for hot flashes. But experts point out that this type of hormone therapy can also increase risks for breast cancer recurrence in survivors.

Gabapentin is usually prescribed to help control some types of epileptic seizures and pain from shingles. The drug has not been approved by the U.S. Food and Drug Administration for treating hot flashes.

In the study, Pandya's team randomly assigned 420 women with breast cancer who were experiencing two or more hot flashes per day to either a placebo, 300 milligrams of gabapentin per day, or 900 milligrams of gabapentin per day, for eight weeks.

Each patient kept a diary on the frequency, severity and duration of hot flashes before the start of the study and during weeks four and eight of treatment, Pandya says.

"When we analyzed the data, we discovered -- much as we had hoped -- that gabapentin was able to reduce the frequency and the severity of hot flashes by close to 46 percent," Pandya says.

"That was particularly apparent for the 900-milligram dose."

Pandya notes that the 300-milligram dose was slightly better than placebo, but not statistically different. "The main effect was seen with the 900-milligram dose," he adds.

"Women who suffer from hot flashes now have another option for control of hot flashes," Pandya says. Many breast cancer patients currently take antidepressants to reduce hot flashes, but those drugs have their drawbacks, he notes. Recent reports show that antidepressants can interfere with the metabolism of tamoxifen and reduce the amount of tamoxifen available in the blood, Pandya explains.

"Gabapentin doesn't interact with any of the drugs," he says.

"We now have a means of controlling hot flashes that is effective with very few, if any, side effects."

One expert cautions that this treatment needs to be tested in other studies before it can be recommended for wide use. "Hot flashes are a serious problem; this type of symptom can be disabling," says Dr. Len Lichtenfeld, deputy chief medical officer of the American Cancer Society. "The study provides another alternative for women with breast cancer to consider for controlling symptoms."

However, Lichtenfeld advises restraint, noting that more evidence is needed. There is no data yet as to whether the drug could have an effect on breast cancer recurrence, or how long the benefit will last, he says.

"As with everything we do in medicine, especially in cancer medicine, you always want to see what other opinions there may be, or other studies to confirm these findings," Lichtenfeld says.

"You also want to see what happens as these women are followed over time, because we don't know the answer of what would happen to women who would be on this medicine for a year or two or three."

Copyright 2005 The New York Times News Service. All rights reserved.