Long-term azathioprine in rheumatoid arthritis: a double-blind study

Several studies have demonstrated the beneficial effect of azathioprine in rheumatoid arthritis. But fears have been expressed about the possible mutagenic and teratogenic effects of prolonged use. If the drug could be withdrawn once remission is achieved, and this remission be then maintained with other agents, the possible complications of long-term therapy might be avoided. A double-blind controlled study was carried out over 8 months in 32 patients receiving long-term azathioprine therapy for rheumatoid arthritis. Substitution of placebo for active drug resulted in clinical deterioration.