A clinical trial of diflunisal against aspirin in osteoarthritis.

Thirty patients with osteoarthritis of knees or hips took part in a double-blind randomized 12-week inter-group clinical trial of diflunisal 250 mg to 375 mg twice daily against aspirin 500 mg to 750 mg four times daily using the double-placebo technique. Changes were assessed in weight-bearing pain and night pain, stiffness after rest, a specified activity, and overall judgements by patient and physician, all graded on a five-point scale. Intermalleolar distance or knee flexion were measured. Side-effects and safety tests were monitored. Diflunisal produced statistically significant responses for all the criteria, when numbers of patients better or worse after 12 weeks were compared using the sign test. Neither the figures for aspirin alone, nor a comparison between the two treatment groups, reached statistical significance. Side-effects and especially dropouts were less on diflunisal. Nine patients on diflunisal but only two on aspirin wanted to continue treatment beyond 12 weeks, though still 'blind' when deciding this. Diflunisal may be a useful, less toxic and longer acting alternative to aspirin in the management of osteoarthritis.