Amiodarone-associated thyroid dysfunction: Current evidence and a practical approach to management

Area of Science:

• Cardiology
• Endocrinology
• Pharmacology

Background:

• Amiodarone, an effective antiarrhythmic, frequently causes thyroid dysfunction, manifesting as amiodarone-induced hypothyroidism (AIH) or thyrotoxicosis (AIT) in 15-20% of patients.
• Thyroid dysfunction poses a significant clinical challenge in patients requiring amiodarone therapy.

Purpose of the Study:

• To review current evidence and guidelines for managing amiodarone-associated thyroid dysfunction.
• To provide a framework for differentiating and treating AIH and AIT phenotypes.

Main Methods:

• A narrative review of randomized trials, prospective cohort studies, systematic reviews, and major guideline documents.
• Literature search conducted on PubMed and Embase (January 2000 - December 2024) using keywords: amiodarone, thyroid dysfunction, thyrotoxicosis, hypothyroidism.
• Emphasis on high-quality evidence and contemporary guidelines from major cardiology and endocrinology societies (ACC/AHA, ESC, ETA, ATA).

Main Results:

• Amiodarone-induced hypothyroidism (AIH) is typically managed with levothyroxine, often without discontinuing amiodarone.
• Amiodarone-induced thyrotoxicosis (AIT) requires phenotypic classification; Type 1 AIT responds to antithyroid drugs, while Type 2 AIT is best treated with corticosteroids.
• Individualized decisions on amiodarone continuation are crucial, weighing thyroid status against cardiac risks.

Conclusions:

• Proactive screening and structured monitoring are essential for identifying amiodarone-associated thyroid dysfunction.
• Phenotype-directed management strategies enable effective treatment of AIH and AIT.
• Integrated management preserves arrhythmia control while addressing thyroid complications.