Getting Botox? Don't Sweat It

Doctors have found a new use for Botox, the wrinkle-smoothing botulism toxin: It seems to curb excessive sweating.

People with a condition called hyperhidrosis produce four or five times the amount of sweat as is normal. There are various treatments, including powerful antiperspirants, drugs to prevent sweat gland stimulation, even surgery on those glands.

Botox, a weakened form of the food-poisoning toxin botulism, already is widely used to treat wrinkles. It is being tried to treat excessive sweating because it seems to temporarily paralyze a nerve that stimulates sweat glands.

Researchers gave 322 patients underarm injections of either Botox or salt water.

They received 12 to 14 injections per armpit. Although injection site pain was the main side effect, lead investigator Dr. Dee Anna Glaser of St. Louis University School of Medicine said the needles are so tiny that most patients weren't bothered.

A month later, 75 percent of the Botox users reported a significant decrease in sweating, compared with a quarter of the placebo patients, said Glaser, who is to present the study at this weekend's American Academy of Dermatology meeting.

Patients could get additional rounds of injections every few months, but 43 percent got relief for a year from the first treatment, Glaser said. The median duration of response was about six months.

Allergan Inc., the maker of Botox, funded the study, which was submitted to the Food and Drug Administration in hopes of formal approval of the drug's new use, Glaser said. But dermatologists already are offering Botox to hyperhidrosis patients; such off-label prescription is legal.

Treatment costs about $1,000 for both arms, she said.