Amiodarone ( Cordarone ) is known to affect the thyroid, but little is known about thyroid recovery after short-term Amiodarone treatment.
Researchers have evaluated the impact of 8 weeks of Amiodarone treatment on thyroid function in patients with atrial fibrillation undergoing catheter ablation in a randomised, double-blind clinical trial.
212 patients referred for atrial fibrillation ablation at two centres were randomized to 8 weeks of oral Amiodarone or placebo.
Thyroid function tests ( TSH, thyroid stimulating hormone; T4, thyroxine; T3, triiodothyronine; fT4, free T4; fT3, free T3 ) were performed at baseline and 1, 3 and 6 months.
Amiodarone was discontinued due to mild thyroid dysfunction in 1 patient in the placebo versus 3 in the Amiodarone group ( p=0.6 ).
In linear mixed models there were significant effects of Amiodarone on thyroid function tests, modified by follow-up visit ( p less than 10-9 for both TSH, T4, T3, fT4 and fT3 ).
The Amiodarone group had higher TSH, fT4 and T4 after 1 and 3 months compared to placebo, whereas T3 and fT3 were lower.
In all cases, the Amiodarone-induced thyroid dysfunction was largest at 1 month, declining at 3 months, and with no differences at 6 months, compared to baseline.
In conclusion, Amiodarone has a significant impact on thyroid function after only 1month, but with a fast recovery of thyroid function after Amiodarone discontinuation.
The study has indicated that short-term Amiodarone can be considered safe in patients without prior thyroid dysfunction. ( Xagena )
Diederichsen SZ et al, Eur J Intern Med 2016; Epub ahead of print