Endocrine Abstracts

Introduction: Amiodarone-induced thyrotoxicosis (AIT) contributes to increased morbidity and mortality in patients invariably having underlying heart disease. In clinical practice, amiodarone therapy often needs to be restarted. When amiodarone is reintroduced, what happens then?

Objective: The aim of study is to evaluate the progression of thyroid function after reinstitution of amiodarone in patients with a previous history of AIT. Secondarily, to determine the efficacity of thionamides to prevent the recurrence of AIT.

Methods: Retrospectively, between 2000 and 2011, patients with a previous history of AIT, in whom amiodarone needed to be reintroduced, were included. Type and severity of 1st AIT, and thyroid function evolution after reinstitution of amiodarone where investigated.

Results: patients were included in our study. Mean age when AIT diagnosed was 62.2±16 years old with male sex predominance. 65.8% of patients had type I AIT. Duration of treatment with amiodarone before developing AIT was shorter in these patients in comparison to patients with type II AIT (20.5±20.1 vs 40.2±20.0 months: P=0.006). Before reinstitution of amiodarone, 6 patients had radical treatment. In 22 patients, amiodarone was reintroduced without a prophylactic therapy, while a thionamide was introduced in parallel with amiodarone reinstitution in 24 patients. After a mean follow up of 34.9±39.1 months, AIT recurred in 14 (29.8%) patients, 12 (25.5%) patients developed hypothyroidism and 20 (48.6%) patients had normal thyroid function. Hyperthyroidism recurred in 62% of patients with amiodarone reinstitution without a preventive treatment, in parallel, only 16% of patients with a prophylactic thionamide suffered from recurrent AIT. Prophylactic thionamide may prevent recurrence of hyperthyroidism (P=0.06).

Conclusion: During median follow up of 3 years after reintroduction of amiodarone, the risk of recurrence of hyperthyroidism tends to be high (29.8%) but not compulsory. A prophylactic treatment with a thionamide could prevent or decrease recurrence of hyperthyroidism.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector