Parenteral high dose methotrexate and sulfasalazine are the only two agents with well demonstrated published efficacy in psoriatic arthritis. The magnitude of the effect seen with azathioprine, etretinate, oral low dose methotrexate and perhaps colchicine suggests that they may be effective but that further multicentre clinical trials are required to establish their efficacy. Furthermore, the magnitude of the improvement observed in the placebo group strongly suggests that uncontrolled trials should not be used to guide management decisions in this condition.
Sulphasalazine in psoriatic arthritis: a double-blind placebo-controlled study.
Sulphasalazine (SASP) is now accepted as an effective slow-acting antirheumatic drug for treating active rheumatoid arthritis (RA), but has not been previously evaluated in psoriatic arthritis. An earlier open study suggested that it was well tolerated and potentially beneficial. The present double-blind placebo-controlled trial of 30 patients has now confirmed its efficacy. Greater improvement occurred in those patients on active treatment than on placebo, with more benefit being detected in those patients with the symmetrical polyarticular but seronegative pattern of arthritis associated with a high acute-phase response. SASP was stopped in 26% because of side-effects but these were mild. No exacerbation or remission of psoriasis was observed. Further studies are in progress to determine the degree of efficacy of SASP in different clinical subgroups of psoriatic arthritis.