AVOID USING ANY DRUG CAUSING INCREASE IN QT INTERVAL LIKE ERYTHROMYCIN, TERFENADINE, ASTEMIZOLE, PROBUCOL, QUINIDINE, AMIODARONE, PROCAINAMIDE, DISOPYRAMIDE, BRETYLIUM, BEPRIDIL, SOTALOL, TRICYCLIC ANTIDEPRESSANT.ANTIMALARIAL ACTION POTENTIATED BY OXIDANT DRUGS. ADDITIVE EFFECT SEEN WITH CHLOROQUINE. ANTAGONISTIC EFFECT SEEN WITH PYRIMETHAMINE AND SULFONAMIDES.