Azathioprine in rheumatoid arthritis: a long-term follow-up study

In 1973 we reported the beneficial effects of azathioprine in a double blind, cross-over study in 17 patients with classic rheumatoid arthritis. During subsequent follow-up over a mean period of 40 months, 4 patients had discontinued therapy because of poor therapeutic response and 1 because of nausea. Eleven of the 12 patients still taking azathioprine had maintained their initial beneficial response or showed further improvement. Adverse side effects during the follow-up period were minor. They included nausea in 1 patient and leukopenia with thrombocytopenia in another. An increased incidence of chromosomal abnormalities was detected in those patients still receiving azathioprine.