Drug dulls shingles, diabetes pain.

A drug called gabapentin effectively reduces nerve pain associated with diabetes and shingles, two studies in the Dec. 2, 1998 JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION show. Roughly half of all long-term diabetes patients experience neuropathy, a painful inflammation of nerves. These patients complain of sharp pain, such as pins-and-needles or burning sensations "like an electrical current," says neurologist Miroslav Backonja of the University of Wisconsin-Madison.

Backonja and his colleagues measured gabapentin's effects by testing it in patients whose neuropathy had lasted from 1 to 5 years. The patients kept a daily log using a scale in which 0 represented no pain and 10, severe pain.

Seventy patients who received the drug for the full 8-week study rated their pain at an average of 6.4 before taking the drug and 3.9 afterward. Another 65 patients who received an inactive substance, or placebo, instead of the drug rated their pain at 6.5 before taking the pill and 5.1 afterward. Neither researchers nor patients knew which pills were placebos.

Meanwhile, a research team led by scientists at the University of California, San Francisco finds that gabapentin also works better than a placebo in counteracting pain from shingles, a viral disease that attacks nerve endings.

These two trials suggest that gabapentin may prove to be "the drug of first choice" in most cases of shingles and in some cases of diabetic neuropathy, say Phillip A. Low and Rose M. Dotson of the Mayo Clinic in Rochester, Minn., in an editorial accompanying the studies.

Gabapentin is approved by the Food and Drug Administration to control convulsions in epilepsy, but Backonja says some doctors already prescribe it for neuropathy pain. Precisely how it works remains unknown.