Amiodarone and the thyroid gland
Around 1 in 6 patients taking amiodarone develop thyroid dysfunction
The pathophysiology of amiodarone-induced hypothyroidism (AIH) is thought to be due to the high iodine content of amiodarone causing a Wolff-Chaikoff effect*
Amiodarone may be continued if this is desirable
Amiodarone-induced thyrotoxicosis (AIT) may be divided into two types:
Unlike in AIH, amiodarone should be stopped if possible in patients who develop AIT
*an autoregulatory phenomenon where thyroxine formation is inhibited due to high levels of circulating iodide
Amiodarone-induced hypothyroidism
The pathophysiology of amiodarone-induced hypothyroidism (AIH) is thought to be due to the high iodine content of amiodarone causing a Wolff-Chaikoff effect*
Amiodarone may be continued if this is desirable
Amiodarone-induced thyrotoxicosis
Amiodarone-induced thyrotoxicosis (AIT) may be divided into two types:
| AIT type 1 | AIT type 2 | |
|---|---|---|
| Pathophysiology | Excess iodine-induced thyroid hormone synthesis | Amiodarone-related destructive thyroiditis |
| Goitre | Present | Absent |
| Management | Carbimazole or potassium perchlorate | Corticosteroids |
Unlike in AIH, amiodarone should be stopped if possible in patients who develop AIT
*an autoregulatory phenomenon where thyroxine formation is inhibited due to high levels of circulating iodide