Comparison of sulfasalazine and placebo in the treatment of psoriatic arthritis. A department of veterans affairs cooperative study

Objective. To determine whether sulfasalazine (SSZ) at a dosage of 2,000 mg/day is effective for the treatment of active psoriatic arthritis (PsA) resistant to nonsteroidal antiinflammatory drug therapy. Methods. Two hundred twenty‐one patients with PsA were recruited from 15 clinics, randomized (double‐blind) to SSZ or placebo treatment, and followed up for 36 weeks. Treatment response was based on joint pain/tenderness and swelling scores and physician and patient global assessments. Results. Longitudinal analysis revealed a trend favoring SSZ treatment (P = 0.13). At the end of treatment, response rates were 57.8% for SSZ compared with 44.6% for placebo (P = 0.05). The Westergren erythrocyte sedimentation rate declined more in the PsA patients taking SSZ than in those taking placebo (P < 0.0001). Adverse reactions were fewer than expected and were mainly due to nonspecific gastrointestinal complaints, including dyspepsia, nausea, vomiting, and diarrhea. Conclusion. SSZ at a dosage of 2,000 mg/day is well tolerated and may be more effective than placebo in the treatment of patients with PsA.