Hydroxyzine hydrochloride: possible adverse cardiac interactions.

Hydroxyzine hydrochloride may produce abnormal ventricular repolarization when given in substratial doses or to susceptible individuals. Phenothiazines, such as thioridazine, tricyclic antidepressants, or antiparkinson drugs, any of which may be given concurrently to psychiatric patients, may augment this effect as well as atropine, quinidine or procainamide. Such EKG abnormalities may increase the likelihood of dysrhythmias and sudden death.