Tocainide, an investigational antiarrhythmic drug with chemical and pharmacologic properties similar to those of lidocaine, is effective when administered orally in treating ventricular arrhythmias (1-4). At present tocainide is not in clinical use in the United States or Europe, but its efficacy strongly suggests that it will soon be introduced for clinical use. Typical doses are between 400 and 800 mg every 8 hours. The commonest side effects have been anorexia, nausea, lightheadedness, tremors, sweating, hot flashes, anxiety, paresthesia, vomiting, abdominal pain, and altered vision and hearing. No pulmonary complications appear to have been reported. A single reported incident of