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(Continued )

Class III antiarrhythmic agents

Amiodarone 400–600 mg QD in divided doses for 2–4 wk (loading dose); followed by 100– 200 mg QD (maintenance dose) Up to 1200 mg QD may be considered in an inpatient monitoring setting (loading dose); up to 200 mg QD maintenance (to minimize long-term adverse effects) Bradycardia, QT prolongation, torsades de pointes (rare), gastrointestinal upset, constipation, hypothyroidism, hyperthyroidism, pulmonary fibrosis, hepatic toxicity, corneal deposits, optic neuritis, peripheral neuropathy, photosensitivity, adult respiratory distress syndrome after cardiac or noncardiac surgery (rare) •  Sinus or AV conduction disease (in absence of pacemaker) •  Inflammatory lung disease •  Hepatic dysfunction •  Hypothyroidism, hyperthyroidism •  Peripheral neuropathy •  Abnormal gait/ataxia •  Optic neuritis •  Drugs with SA and/or AV nodal–blocking properties •  Amiodarone is a substrate of and inhibits P-glycoprotein and CYP2C9 (moderate), CYP2D6 (moderate), and CYP3A4 (weak); amiodarone is a substrate for CYP3A4 (major) and CYP2C8 (major); amiodarone is an inhibitor of OCT2 •  Reduce warfarin dose by 50%, and reduce digoxin dose by 30%–50% •  Agalsidase alfa, agalsidase beta, azithromycin, bosutinib, ceritinib, colchicine, dabigatran, edoxaban, flecainide, ivabradine, ledipasvir/sofosbuvir, lopinavir, lopinavir/ ritonavir, lovastatin, nelfinavir, pazopanib, propafenone, simvastatin, ritonavir, rivaroxaban, saquinavir, sofosbuvir, topotecan, vincristine, grapefruit juice Dofetilide 500 mcg every 12 h (if CrCl >60 mL/min)

250 mcg every 12 h (if CrCl 40–60 mL/min) 125 mcg every 12 h (if CrCl 20 to <40 mL/min) Not recommended if CrCl <20 mL/min Adjust dose for renal function, body size, and age Initiate for minimum of 3 d in a facility that can provide continuous ECG monitoring and cardiac resuscitation Contraindicated if the baseline QTc interval or QTc >440 ms† or 500 ms in patients with ventricular conduction abnormalities Repeat ECG 2–3 h after administering the first dose to determine QTc; if the QTc increased by >15% compared with baseline or if QTc is >500 ms† (550 ms in patients with ventricular conduction abnormalities), subsequent dosing should be down titrated by 50%; at 2–3 h after each subsequent dose, determine QTc (for in-hospital doses 2–5); if at any time after the second dose the QTc is >500 ms║ (550 ms in patients with ventricular conduction abnormalities), dofetilide should be discontinued QT prolongation, torsades de pointes •  Severe renal dysfunction (contraindicated if CrCl <20 mL/min) •  Prolonged QT •  History of torsades de pointes •  Concomitant use of hydrochlorothiazide, cimetidine, dolutegravir, itraconazole, ketoconazole, megestrol, trimethoprim, prochlorperazine trimethoprim/ sulfamethoxazole or verapamil, contraindicated •  Avoid other QT-prolonging drugs

Sotalol 40–80 mg every 12 h (Patients initiated or reinitiated on sotalol should be placed in a facility that can provide cardiac resuscitation and continuous electrocardiographic monitoring for a minimum of 3 d). Contraindicated if the QTc† interval is >450 ms.

CrCl should be calculated before dosing. If CrCl >60 mL/min, then dosing frequency is twice daily. If CrCl 40–60 mL/min, dosing interval is every 24 h. If CrCl <40 mL/min, should not be used.) 160 mg every 12 h (During initiation and titration, the QT interval should be monitored 2–4 h after each dose. If the QT interval prolongs to ≥500 ms, the dose must be reduced or the drug discontinued.) QT prolongation, torsades de pointes, bradycardia, bronchospasm •  Prolonged QT

•  Renal dysfunction •  Hypokalemia •  Diuretic therapy •  Avoid other QT-prolonging drugs •  Sinus or AV nodal dysfunction (in absence of pacemaker) •  Decompensated systolic HF •  Cardiogenic shock •  Reactive airway disease •  Drugs with SA and/or AV–nodal blocking properties

Table 7.  Continued

Drug Initial Daily Dose(s) Maximum Total Daily

Maintenance Dose Potential Adverse

Effects Precautions (Exclude or Use With Caution) and Interactions

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