- Concomitant use of any of the following drugs, reported to increase the QT interval: antiarrhythmics class IA (e.g. quinidine, hydroquinidine, disopyramide) or antiarrhythmics class III (e.g., amiodarone, sotalol, dofetilide, ibutilide), neuroleptics (e.g. phenothiazines, pimozide, sertindole, haloperidol, sultopride), tricyclic antidepressive agents, certain antimicrobials (sparfloxacin, erythromycin IV, pentamidine, antimalarials, particularly halofantrine), certain antihistaminics (terfenadine, astemizole, mizolastine), and others (cisapride, vincamine IV, bepridil, diphemanil)