Procainamide-induced agranulocytosis

We have described six new patients accounting for seven episodes of agranulocytosis due to procainamide. Six episodes involved the slow-release oral preparation. With continued use of this convenient antiarrhythmic agent, it is important that physicians be alert to the possibility of agranulocytosis in febrile patients receiving procainamide. If agranulocytosis occurs, procainamide should be discontinued promptly and the fever should be treated aggressively with combination broad spectrum antibiotics.