Double-blind crossover study to evaluate the efficacy of a single daily dose of naproxen in rheumatoid arthritis.

Three dosage schedules of naproxen--1000 mg in the morning and placebo in the evening, 1000 mg in the evening and placebo in the morning, and 500 mg in the morning and again in the evening--were compared for efficacy in treating rheumatoid arthritis in a 13-week, double-blind, crossover study. After a 1-week washout, 48 patients were assigned randomly according to a Latin Square design to one of three dosage sequence groups, each consisting of three 4-week treatment phases. Each group experienced decreases in pain, number of affected joints, morning stiffness, ARA classification, and disease activity evaluated by both patient and physician. The three dosage schedules provided the same therapeutic results, with few and mild side effects. This study indicates that a single daily dose of naproxen can be used to treat rheumatoid arthritis safely and effectively.