Once weekly administration of levamisole in rheumatoid arthritis.

The therapeutic as well as the unwanted effects, in rheumatoid arthritis patients, of once weekly administration of 150 mg levamisole were compared, under double-blind conditions, with 3 50-mg daily doses of levamisole for 3 consecutive days weekly and placebo. The applied minimization method was used to assign patients to treatment groups so that all groups were comparable at the start of the trial. All patients were evaluated monthly, for 26 weeks. Three patients on the levamisole 3-day-weekly dosage interrupted their treatment because of side-effects. Except for the unwanted effects, the differences in the therapeutic efficacy in the 2 levamisole groups were not statistically significant. Twenty-one patients (3 in the levamisole once weekly administration group and 18 in the placebo group) interrupted their treatment because of inefficacy. Placebo was statistically less effective than the active drug. It is concluded that once weekly is as effective as 3-day-weekly administration of levamisole, but has fewer side-effects.