or diphenhydramine. Assisted ventilation may be needed. Cardiac dysrhythmias (eg, prolonged QRS and QT intervals, monomorphic and polymorphic (torsades de pointes [TdP]) ventricular dysrhythmias) developed in 5 patients with a history of loperamide abuse (doses: 70 mg to 792 mg daily). Treatment with standard anti-arrhythmic agents were ineffective; however, electrical overdrive pacing or isoproterenol continuous infusion were effective in treating dysrhythmias and preventing further episodes of TdP.