Amiodarone use is associated with thyroid dysfunction, including thyrotoxicosis and hypothyroidism, necessitating baseline screening and periodic monitoring of thyroid function.
How should amiodarone-induced thyroid dysfunction be managed?
Amiodarone-induced thyroid dysfunction requires specific management strategies based on the type of dysfunction, highlighting the importance of routine thyroid function monitoring.
Amiodarone is a potent antiarrhythmic drug associated with thyroid dysfunction. Its high iodine content causes inhibition of 5'-deiodinase activity. Most patients remain euthyroid. Amiodarone-induced thyrotoxicosis (AIT) or amiodarone-induced hypothyroidism (AIH) may occur depending on the iodine status of individuals and prior thyroid disease. AIT is caused by excess iodine-induced thyroid hormone synthesis (type I AIT) or by destructive thyroiditis (type II AIT). If the medical condition allows it, discontinuation of the drug is recommended in type I AIT. Otherwise, large doses of thioamides are required. Type II AIT is treated with corticosteroids. Mixed cases require a combination of both drugs. Potassium perchlorate has been used to treat resistant cases of type I AIT but use is limited by toxicity. Thyroidectomy, plasmapheresis, lithium, and radioiodine are used in select cases of AIT. AIH is successfully treated with levothyroxine. Screening for thyroid disease before starting amiodarone and periodic monitoring of thyroid function tests are advocated.
Hema Padmanabhan (2010) conducted a review in Amiodarone-induced thyroid dysfunction. Amiodarone was evaluated. Amiodarone use is associated with thyroid dysfunction, including thyrotoxicosis and hypothyroidism, necessitating baseline screening and periodic monitoring of thyroid function.