amiodarone hydrochloride: clinical use

Prescribing considerations

• Initiate and normally monitor under hospital or specialist supervision; reserve for serious arrhythmias when alternatives are unsuitable or ineffective.
• Review concomitant medicines for QT prolongation, bradycardia, electrolyte depletion and CYP or P-glycoprotein interactions.
• Correct potassium and magnesium abnormalities before treatment.
• Advise about photosensitivity, respiratory and visual warning symptoms, and persistence of toxicity and interactions after withdrawal.

Contraindications and cautions

• Hypersensitivity to amiodarone, iodine or a formulation excipient.
• Sinus bradycardia, sinoatrial block, severe conduction disease or sinus-node dysfunction without appropriate pacing.
• Evidence or history of thyroid dysfunction.
• Combination with medicines capable of inducing torsades de pointes.
• Pregnancy except exceptional circumstances, and breastfeeding.

Monitoring

• Before treatment: ECG, thyroid and liver function, potassium, magnesium, renal function and chest imaging.
• Once stable: thyroid and liver function, renal function and electrolytes approximately every six months, with periodic ECG review.
• Continue thyroid surveillance for several months after discontinuation.
• Investigate new respiratory symptoms promptly and arrange prompt ophthalmological assessment for blurred or reduced vision.

Clinical pharmacology

A highly lipophilic, iodine-containing anti-arrhythmic with multichannel and anti-adrenergic actions. Its active metabolites, CYP and P-glycoprotein inhibition, and long, variable elimination half-life mean benefits, toxicity and interactions may persist after withdrawal.

Formulation and product differences

• The tablet is intended for oral stabilisation and longer-term treatment and contains lactose.
• The intravenous concentrate is used when rapid treatment is needed or oral administration is not possible; it requires monitored administration and product-specific dilution and compatibility procedures.
• The selected intravenous product contains benzyl alcohol, with additional restrictions and cautions in neonates, young children, pregnancy and patients at risk of excipient accumulation.

Injection

Route: Parenteral

Strengths: 30 mg/mL, 50 mg/mL, 150 mg/3 mL