Comparative double-blind trial of intra-articular injections of two long-acting forms of betamethasone.

Two injectable betamethasone preparations, betamethasone dipropionate/betamethasone phosphate and betamethasone acetate/betamethasone phosphate were compared in a controlled trial on 22 "matched patient pairs" with rheumatic diseases. The two preparations were injected intra-articularly in knee joints affected by active synovitis. The time until onset of action and the duration of clinically adequate anti-inflammatory effect were recorded. All injections produced clinically significant effects. The interval before recurrence of symptoms varied from 2 days to more than 3 months. The dipropionate form showed statistically significantly longer duration of action. No difference was noted in the time until onset of action. Local side effects were not observed. The double-blind method of clinical evaluation proved useful in comparing duration of action between long-acting corticosteroids.