Concomitant use w/ grapefruit juice. Patients w/ known QT interval prolongation; uncorrected hypokalemia; ongoing proarrhythmic conditions eg, clinically significant bradycardia & acute myocardial ischemia. Renal or hepatic insufficiency. Pregnancy & lactation. Tab: Galactose intolerance, Lapp lactase deficiency or glucose-galactose malabsorption. Not recommended in childn <12 yr. Elderly ≥65 yr. Oral soln: Concomitant use w/ simvastatin, lovastatin, cyclosporin, tacrolimus, sirolimus, everolimus, cisapride. Fructose intolerance, glucose/galactose malabsorption or sucrase-isomaltase insufficiency. Contains sucrose & methyl parahydroxybenzoate. Childn <2 yr.