Hypotension Incidence with Amiodarone
Hypotension is the most common adverse reaction with intravenous amiodarone, occurring in approximately 16% of patients, though the incidence varies significantly based on formulation and administration rate. 1
Intravenous Amiodarone Hypotension Rates
Standard Formulation (Cordarone IV)
- Treatment-emergent, drug-related hypotension occurs in 16% (288 of 1,836 patients) receiving intravenous amiodarone. 1
- Clinically significant hypotension requiring alterations in therapy occurs in approximately 3% of patients. 1
- Permanent discontinuation due to hypotension is required in less than 2% of patients. 1
- The hypotension is not dose-related but appears related to the rate of infusion, typically occurring most often in the first several hours of treatment. 2, 1
Severity and Clinical Context
- In high-dose intravenous amiodarone protocols (5 mg/kg bolus followed by 20-30 mg/kg/day), serious hypotension occurred in 8 of 35 patients (23%) with recurrent refractory ventricular tachycardia. 3
- During cardiac surgery, intravenous amiodarone loading decreased mean arterial pressure by 14 mm Hg at 6 minutes, with hypotension requiring intervention in 3 of 15 patients (20%). 4
- In some cases, hypotension may be refractory and result in fatal outcomes. 1
Mechanism and Time Course
- The hypotension is primarily caused by selective arterial vasodilation rather than negative inotropy, as left ventricular systolic performance is generally preserved. 4
- The standard formulation's vasoactive solvents (polysorbate 80 and benzyl alcohol) contribute significantly to the hypotensive effect. 5, 6
- The hypotensive effect is most pronounced in the first 15 minutes after administration and is typically transient. 4
- Cardiac index may decrease at 10 minutes but typically returns to baseline by 60 minutes. 7
High-Risk Populations
- Patients with overt heart failure, severely depressed left ventricular ejection fraction, and marked baseline hemodynamic abnormalities are at highest risk for profound hypotension. 7
- Hemodynamic monitoring is preferable in these high-risk patients. 7
- The American College of Cardiology recommends particular caution in patients with bradycardia (heart rate <60 bpm), hypotension (systolic blood pressure <100 mmHg), and moderate or severe left ventricular failure. 8
Oral Amiodarone
- Hypotension is not listed as a potential adverse effect with oral amiodarone formulations, which primarily cause bradycardia, QT prolongation, and gastrointestinal upset. 2
- Long-term oral amiodarone administration has shown no reduction in left ventricular function even in patients with severely reduced myocardial performance. 7
Management Strategies
- Initial management involves slowing the infusion rate. 1
- Additional standard therapy may include vasopressor drugs, positive inotropic agents, and volume expansion. 1
- The initial rate of infusion should be monitored closely and should not exceed recommended rates (150 mg IV bolus over 10 minutes for life-threatening arrhythmias). 2, 1