A widely used drug that has been mired in controversy for most of its decade-long life may now bring relief to postmenopausal women whose lives have been disrupted by unrelenting hot flashes. The relief may be especially welcome to women who have had breast cancer and cannot take estrogen. The drug, best known by its trade name, Neurontin, but now prescribed generically as gabapentin, was approved by the Food and Drug Administration in 1994 to treat epileptic seizures. In 2002, it was approved to treat postherpetic neuralgia, horrific pain that sometimes follows shingles. Aided by the Internet and, the government...