Epilepsy drug eases diabetes woes. (Biomedicine).

The epilepsy drug topiramate can alleviate intense finger and toe pain in people with diabetes and also seems to help them lose weight, two studies show.

Diabetes is the most common cause of neuropathy, a condition in which poor blood flow in the extremities and the accumulation of reactive oxygen species such as hydrogen peroxide can damage nerves. A person with neuropathy can feel numbness or sharp pain in the fingers and toes.

Topiramate benefits epilepsy patients by limiting damage to their nerve cells. This protective effect inspired researchers to give the drug to 11 people with type 2, or adult-onset, diabetes.

The volunteers, average age 60, had significantly less pain by the end of the 8-week trial and showed reduced blood pressure, blood sugar, and cholesterol, says Aaron I. Vinik of the Eastern Virginia Medical School in Norfolk.

Earlier studies suggested that topiramate mitigates a self-destruct signal in sensory nerve cells of diabetic patients. That seems to induce nerve rebuilding, says Vinik. "In the past, it would have been heretical to say nerves can regrow," he says, but measures of nerve-fiber density in these patients suggest it's happening.

In another study, Arne Astrup of the Royal Veterinary and Agricultural University in Copenhagen and his colleagues found that topiramate helps diabetes patients keep off extra weight.

The researchers enrolled 288 people who had lost 8 percent of their weight on a strict low-calorie diet coupled with regular exercise. The scientists gave topiramate to 191 of these patients and an inert pill to the rest. After 44 weeks, three-fourths of the people in the topiramate group, compared with only one-third of volunteers getting the placebo, had maintained their weight or lost more pounds.--N.S.