Amiodarone (
Cordarone) has been proven to be useful in the management of
atrial fibrillation. However, because of a large
iodine content, this
drug is not used in this complication of
thyrotoxicosis. We previously have observed a greater fall in serum T3 and T4 concentrations in
hyperthyroid patients treated with
amiodarone and
methimazole than with
methimazole alone. In the present study, we determined whether the addition of
amiodarone to
propylthiouracil (PTU) could improve the levels of circulating
thyroid hormones in
hyperthyroid patients, and we assessed the release of
iodide from
amiodarone by measuring the 24 h urinary
iodine excretion. Twelve
hyperthyroid patients were treated either with PTU, 600 mg daily for 10 days (group PTU), or with
amiodarone (A), 1200 mg daily for 3 days in addition to PTU (group A-PTU). Basal serum T4, T3, and rT3 concentrations (mean +/- SEM) were respectively 206 +/- 13 nmol/L, 5.13 +/- 0.8 nmol/L, and 81 +/- 7 ng/dL for group PTU and 238 +/- 39 nmol/L, 4.73 +/- 1.06 nmol/L, and 84 +/- 12 ng/dL for group A-PTU (NS). In group A-PTU, plasma
amiodarone peaked on day 3 (mean +/- SEM: 0.48 +/- 0.11 mg/L), and urinary
iodine reached 5.27 +/- 1.28 mg/day on day 5. The fall in serum T3 and the increase in serum rT3 concentrations were significantly greater in group A-PTU than in group PTU (ANOVA, p less than 0.05). In group A-PTU, the minimal serum T3 concentration was observed on day 5 of treatment (28 +/- 6% of the pretreatment values).(ABSTRACT TRUNCATED AT 250 WORDS)