Nexterone

Interactions may persist months after discontinuing. Increased risk of torsade de pointes with QT prolonging drugs (eg, class I or III antiarrhythmics, lithium, certain phenothiazines, tricyclic antidepressants, certain fluoroquinolones or macrolides, azole antifungals, halogenated inhalation anesthetics); avoid. Potentiated by CYP3A4 inhibitors (eg, certain fluoroquinolones or macrolides, azole antifungals, grapefruit juice, cimetidine); avoid. Potentiates antiarrhythmics (eg, quinidine, procainamide, flecainide); reserve concomitant use for those who are unresponsive to a single agent; reduce their doses by 30–50% for several days after transitioning to oral amiodarone. Potentiates cyclosporine, digoxin (reduce digoxin dose by ½ or discontinue), warfarin (reduce anticoagulant dose by ⅓ to ½ and monitor INR), phenytoin, lidocaine; monitor. Myopathy with statins metabolized by CYP3A4; limit simvastatin dose to 20mg daily or lovastatin dose to 40mg daily. Additive bradycardia, sinus arrest, and AV block with β-blockers, digoxin, verapamil, diltiazem, ivabradine, clonidine; monitor heart rate. Exacerbation of arrhythmias with antiarrhythmics. Symptomatic bradycardia when co-administered with sofosbuvir. Antagonized by St. John’s wort, cholestyramine. May affect thyroid function tests. See full labeling.