Amiodarone-Induced Thyrotoxic Thyroiditis: A Diagnostic and Therapeutic Challenge

Table 1

Effects of amiodarone on thyroid function tests in euthyroid patients.

Test	Duration of treatment
	Subacute (<3 months)	Chronic (>3 months)
T4	Modest increase	Remains increased by up to 40% above baseline; may be in high reference range or moderately raised
T3	Decreased, usually to low reference range	Remains in low reference range or slightly low
TSH	Transient increase (up to 20 mU/L)	Normal, but there may be periods of high or low values
rT3	Increased	Increased

Used with permission from Heart (Newman et al. 1998 [3]).