THIORIDAZINE HYDROCHLORIDE (MELLARIL) - ITS EFFECT ON ELECTROCARDIOGRAM AND A REPORT OF 2 FATALITIES WITH ELECTROCARDIOGRAPHIC ABNORMALITIES

  • 1 January 1963
    • journal article
    • research article
    • Vol. 89  (11) , 546-+
Abstract
Twenty-eight ecg''s are presented which depict a quinidine-like effect of thioridazine on ventricular repolarization, in doses as low as 200 mg a day. T waves are flattened out and sometimes inverted. Occasionally S-T segments have become convex and U waves have appeared. Case reports are presented of 2 patients who died while receiving large doses of thioridazine, 1500 and 3600 mg daily, respectively. Terminal ecg patterns in each instance were those of heart block, alternating with episodes of ventricular tachycardia. The myocardium of 1 of the fatal cases revealed edema, increased vascularity, and some increase in connective tissue elements, along with fragmentation of muscle fibres. These changes were most pronounced in the interventricular septum. It is concluded that, because of the quinidine-like action of thioridazine on ventricular repolarization, caution is indicated when it is administered in large doses.