Treatment of frey's syndrome with topical 2% diphemanil methylsulfate (prantal®): A double‐blind evaluation of 15 patients

Abstract
Fifteen patients with severe gustatory sweating after total parotidectomy and facial nerve preservation were asked to take part in a double-blind study. All patients were alternatively treated with topically applied placebo and topically applied 2% diphemanil methylsulfate (an anticholinergic agent). A 10-day period was allowed between applications for return of symptoms. Two-percent diphemanil methylsulfate provided partial relief in 33.3% of patients and total relief in 40% of patients. Involvement of the hairy temporal line region with gustatory sweating was the main reason for failure. Duration of relief varied from 2 to 4 days. The only side effect was dryness of the mouth noted in two patients.