The Frequency of Procainamide‐induced Systemic Lupus Erythematosus

Of 61 patients taking procainamide for longer than one month, three (4.9%) were found to have systemic lupus erythematosus. Five other patients with the syndrome were referred to us because it was suspected they were developing systemic lupus. Difficulties in definition of the syndrome are outlined; three other patients might have been included. The relevance of both the clinical assessment and the laboratory investigations in screening patients taking procainamide is discussed.