[Amiodarone and thyroid disorders--prospective study and review of the literature]

Abstract

A well-known adverse effect of amiodarone is the induction of thyroid dysfunction. The numerous studies evaluating the incidence of amiodarone-induced thyroid dysfunction have given very dissimilar results, because of the variability in the criteria of hyper- and hypothyroidism, on the one hand, and in the iodine intake of the studied population on the other hand. The aim of our study was to evaluate the incidence of amiodarone-induced thyroid dysfunction. One hundred and twelve patients without prior thyroid dysfunction or anterior treatment with amiodarone were included in the study. Thirty-one patients were later excluded from the analysis because of a follow-up duration of less than four months. So our analysis concerned 81 patients (52 men and 29 women), followed for a mean period of 37.3 months. Amiodarone-Induced Thyrotoxicosis (AITT), diagnosed by the association of a low TSH and a high T4 (free and total T4), occurred in 13 patients (16%). Male sex proved to be a statistically significant risk factor of AITT. The normalization of the thyroid tests was obtained by the withdrawal of amiodarone and, for most of the patients, by the addition of thionamides. Amiodarone-Induced Hypothyroidism (AIHT), diagnosed by the elevation of TSH, occurred in 10 patients (12.3%). Female sex proved to be a statistically significant risk factor of AIHT.