Increased absorption w/ food. Avoid use w/ strong CYP3A4 inducers eg, phenytoin, carbamazepine, rifampicin, rifabutin, rifapentine, phenobarb, St. John's wort. Increased PSA levels w/ spironolactone. Caution w/ drugs prolonging QT interval & inducing Torsade de pointes eg, class IA (eg, quinidine, disopyramide) or III (eg, amiodarone, sotalol, dofetilide, ibutilide) antiarrhythmics, methadone, moxifloxacin, antipsychotics; CYP2D6 & CYP2C8 inhibitors; CYP2D6-metabolised drugs eg, metoprolol, propranolol, desipramine, venlafaxine, haloperidol, risperidone, propafenone, flecainide, codeine, oxycodone, tramadol.