Can amiodarone be administered intramuscularly (IM)?

From the Guidelines

No, amiodarone should not be administered intramuscularly (IM). Amiodarone is only approved for intravenous (IV) or oral administration. Intramuscular injection of amiodarone can cause significant tissue damage, pain, and inflammation at the injection site due to its chemical properties. The medication is highly alkaline and contains solvents that can be irritating to muscle tissue. Additionally, IM administration would result in unpredictable absorption and potentially inadequate therapeutic levels.

Key Points to Consider

• When rapid administration is needed for life-threatening arrhythmias, the IV route should be used, typically with a loading dose of 150 mg over 10 minutes, followed by an infusion, as recommended by 1.
• For non-emergent situations, oral amiodarone is appropriate, usually starting with a loading dose of 800-1600 mg daily, followed by maintenance dosing of 200-400 mg daily.
• The pharmacokinetics of amiodarone are complex, with a very long half-life and extensive tissue distribution, which further complicates any non-standard routes of administration, as noted in 1 and 1.

Administration Guidelines

• IV administration is preferred for acute settings, with a recommended dose of 150 mg over 10 minutes, followed by an infusion, as stated in 1.
• Oral administration is suitable for non-emergent situations, with a typical loading dose of 800-1600 mg daily, followed by maintenance dosing of 200-400 mg daily, as mentioned in 1 and 1.

Important Considerations

• Amiodarone can cause potentially fatal toxicity, including pulmonary fibrosis, hepatic injury, and proarrhythmia, as warned in 1.
• High-dose oral amiodarone loading can worsen hemodynamics in patients with recent decompensation of heart failure or hypotension, as cautioned in 1.

From the Research

Administration of Amiodarone

• Amiodarone can be administered orally or intravenously 2, 3, 4, 5, 6.
• The provided studies do not mention the administration of amiodarone via the intramuscular (IM) route.
• The focus of the studies is on the oral and intravenous administration of amiodarone, highlighting its pharmacokinetics, efficacy, and safety in managing various cardiac arrhythmias.

Pharmacokinetics and Efficacy

• Amiodarone has a variable oral bioavailability and undergoes extensive enterohepatic circulation 2.
• It is a potent antiarrhythmic drug with actions of all antiarrhythmic drug classes, making it effective in treating symptomatic and life-threatening ventricular and supraventricular arrhythmias 3, 4, 5.
• The drug has a slow onset of action, requiring a loading dose, and its long-term use is limited by the risk of non-cardiac toxicity and drug-drug interactions 3, 5, 6.

Safety and Monitoring

• Amiodarone has a diverse adverse effect profile, involving various organ systems, and requires regular monitoring to control its well-recognized adverse effects 4, 5, 6.
• Patients treated with amiodarone need close supervision by the treating physician, and long-term treatment should be based on the use of minimal doses for satisfactory arrhythmia outcome 3, 5, 6.