Epilepsy Drug Cools Hot Flashes
Prostate Cancer Treatment Side Effects Also Relieved By Anti-Seizure Drug
Nov. 12, 2002 -- An anti-seizure drug is emerging as an alternative to controversial hormone replacement therapy in helping to relieve the scourge of menopause and one of the most commonly cited side effects of some cancer treatments -- hot flashes.
Both the frequency and severity of hot flashes decreased by about 70% in women after they received varying doses of Neurontin, researchers report in the November issue of Mayo Clinic Proceedings. All 16 women in this first clinical study also reported improvement in other menopause-related symptoms, adds researcher Debra Barton, PhD, RN.
Generically known as gabapentin, Neurontin is a drug usually used to control epileptic seizures, alleviate diabetic foot nerve pain, and prevent migraine headaches.
"Hormone replacement therapy has a lot of negative effects and it's not the standard of care to treat women who have a history of breast cancer or are a higher risk of developing it," she tells WebMD. "There has to be good options available for those women, or others prone to hot flashes who don't want to use HRT. And gabapentin appears to be one of them."
All the women studied experienced "significant relief" during the trial, says Barton, of the Mayo Clinic in Rochester, Minn. They received the anti-seizure medication for four weeks, in increasing doses from 300 to 900 mg. By comparison, it is usually administered in doses from 3,000 to 3,600 mg to treat seizures.
Most of the women (14) in the study had a history of breast cancer and were taking tamoxifen, but the others had no cancer risk and just wanted an alternative to traditional HRT, she says.
Hot flashes are a common side effect of tamoxifen therapy for breast cancer, since it blocks the effects of estrogen and causes symptoms similar to those of menopause. However, hot flashes have also been reported in men undergoing treatment for prostate cancer with the drug Lupron.
"Before this study, the best non-hormonal option out there gave a 40% decrease in hot flashes, which isn't so great when you compare it to hormones that offer 90% relief," Barton says. "Gabapentin comes much closer to traditional HRT efficacy without the side effects. In fact, a majority of the study participants stayed on the medication after the study was completed."
Neurontin became an unlikely treatment for hot flashes by accident nearly three years ago.
"It started with a patient of mine who felt that since she went on estrogen to treat her menopause, her migraine headaches had worsened," says neurologist Thomas Guttuso, MD, of the University of Rochester School of Medicine and Dentistry. "I put her on gabapentin, which can prevent migraines. About a week later, she called me to say that her hot flashes had stopped."
Intrigued, he began recruiting other patients to see if they had a similar experience, and wrote about his observations in the August 2000 issue of Neurology.
Since then, Neurontin has been the subject of several "anecdotal" reports -- many at his school -- suggesting that it can ease hot flashes, particularly in breast cancer patients using tamoxifen and prostate cancer patients on Lupron. Many of those patients reported reductions similar to that noted by the Mayo researchers - around 70%.
"There is no clear evidence on why gabapentin appears to help, but my feeling is that it affects the part of the brain that regulates body temperature," Guttuso tells WebMD.