Phenothiazine-induced ventricular tachycardia following acute overdose

The chronic use of phenothiazine is known to result in ventricular arrhythmias in certain patients. The occurrence of cardiac abnormalities following acute phenothiazine overdose is less well documented. Phenothiazine-induced ventricular tachycardia, when it occurs in the overdose situation, may be refractory to conventional antiarrhythmic drugs. We present a case in which the usual therapy was unsuccessful. Only after a transvenous pacemaker was inserted was the patient's condition reversed.