Amiodarone is a medication commonly used to treat patients with irregular heart beats, or cardiac arrhythmias. Each amiodarone tablet contains considerable amounts of iodine, which is normally utilized by the thyroid gland for synthesis of thyroid hormone. An under active thyroid gland following amiodarone therapy is generally simple to treat, although small doses of thyroid hormone are generally initiated initially in most patients with heart disease.
Hyperthyroidism is patients taking amiodarone is more problematic and can be quite severe.
Furthermore, amiodarone is fat soluble and stored in our fat cells for weeks to months even after the medication is discontinued. Although thyroid function generally returns to normal once amiodarone is discontinued, it must be recognized that for some patients amiodarone is the only medication that successfully controls their irregular heart arrhythmias, which at times can be life threatening. Accordingly, in these clinical situations, patients may need to continue on the amiodarone and the thyroid dysfunction can usually be treated successfully while the patient stays on the drug. Due to the marked iodine content of the medication, patients with amiodarone -associated hyperthyroidism generally do not take up exogenously administered iodine, and hence radioactive iodine treatment of this condition will usually not be an option. Accordingly, medications or surgery are the two treatment regimens of choice for hyperthyroid patients on amiodarone .