Randomized, double-blind study of levamisole in recurrent aphthous stomatitis.

A randomized double-blind study was designed to evaluate the safety and efficacy of levamisole in the treatment of recurrent aphthous stomatitis (RAS). Thirty patients, aged 9-65 years, were selected, based on a documented history of three or more episodes of RAS. Patients were instructed to take 150 mg of levamisole (or placebo) daily for 3 days at the onset of the first prodromal symptoms of an ulcer. The regimen was to be repeated for each new episode, but not more than once per week. At each episode patients were examined and evaluated as to number and duration of ulcers, interval between episodes, pain associated with ulcers, and side effects. Data on 24 patients were suitable for analysis. Of those patients receiving levamisole, six showed slight improvement and five were unchanged. Of those patients receiving the placebo, one showed a marked improvement, four slight improvement, six were unchanged, and two deteriorated. There was neither a clinical nor a statistically significant difference between the groups. It is concluded that levamisole, in this study protocol, had no effect on the incidence or severity of aphthous ulcers.