Rheumatoid arthritis: the effects of treatment with dapsone on hemoglobin.

Hemoglobin concentration (Hb) was measured at 6 week intervals for up to a year in 84 patients with rheumatoid arthritis treated with dapsone. During the first 6 weeks, mean Hb decreased from 12.0 to 11.0 g/dl (p less than 0.001). Falls in Hb occurred in 81% of patients but exceeded 2 g/dl in only 10%. After more than 6 weeks of treatment mean Hb increased, though a few individuals became anemic during this period. Anemia led to discontinuation of dapsone in 5 (6%) patients. Men and patients receiving corticosteroids had higher pretreatment Hb values; after falls in mean Hb at 6 weeks, recovery was more rapid in these 2 subgroups. Changes in Hb produced by 100 mg and 150 mg dapsone daily were similar.