 - Being treated with dofetilide, sotalol, quinidine, other Class Ia and III anti-arrhythmics, sparfloxacin, gatifloxacin, moxifloxacin, halofantrine, mefloquine, pentamidine, arsenic trioxide, levomethadyl acetate, dolasetron mesylate, probucol, tacrolimus, methadone, or clozapine 