Induced torsades de pointes w/ class Ia antiarrhythmics eg, quinidine, disopyramide. Class III antiarrhythmics eg, amiodarone, sotalol. Other medications eg, bepridil, cisapride, sultopride, thioridazine, methadone, erythromycin IV, vincamine IV, halofantrine, pentamidine, sparfloxacin. Reciprocal antagonism w/ levodopa & neuroleptics. Enhance central effects of alcohol. Enhance risk of torsades de pointes or could prolong the QT interval. Bradycardia-inducing medications eg, β-blockers, bradycardia-inducing Ca channel blockers eg, diltiazem & verapamil, clonidine, guanfacine; digitalis. Induce hypokalemia w/ hypokalemic diuretics, stimulant laxatives, amphotericin B IV, glucocorticoids, tetracosactides. Neuroleptics eg, pimozide, haloperidol; imipramine antidepressants; lithium. CNS depressants including narcotics, analgesics, sedative H
1 antihistamines, barbiturates, benzodiazepines & other anxiolytics, clonidine & derivatives. Antihypertensives & other hypotensive medications.