Antithyroid antibodies during amiodarone treatment

Abstract

Abstract. In 44 euthyroid and goitre-free patients, 23 treated with amiodarone (group A) and 21 treated with other antiarrhythmic drugs (group B), antimicrosomal antibodies and antithyroglobulin antibodies were determined before the beginning of treatment and after 7, 15, 30, 60, and 180 days. In group A, none of the patients had antithyroid antibodies before treatment, 1 of 15 patients (6.7%) had antimicrosomal antibodies (titre 1:100) on day 7 only, and 1 of 18 (5.5%) had antithyroglobulin antibodies (titre 1:80) on day 180. In group B, 1 of 21 patients (4.8%) had antimicrosomal antibodies (IgG class) at titre 1:400 before the beginning of treatment, which was negative on day 180, and 2 of 17 (11.8%) had antimicrosomal antibodies (titre 1:100) on day 60 only. None of these patients showed clinical and/or laboratory signs of hyperor hypothyroidism. These data indicated that antithyroid antibodies rarely appear in amiodarone-treated patients and do not differ significantly from patients treated with other antiarrhythmic drugs. The role of autoimmunity and the meaning of antithyroid antibodies in the pathogenesis of amiodarone-induced thyroid dysfunction (mainly of hypothyroidism) in patients without pre-existent thyroid diseases is still unclear.

Disfunção tireoidiana e conduta dos cardiologistas em pacientes usando amiodarona

“…The prevalence of positivity for anti-TPO antibodies was similar to that in studies assessing the development of antithyroid antibodies in patients using amiodarone 42,43 . The high prevalence of thyroid dysfunction in anti-TPO-positive patients found in our case series (80%) suggests that patients with autoimmune thyroid disease are at a greater risk of developing hypothyroidism 44 .…”

The Effects of Amiodarone on the Thyroid*

“…These results were not, however, confirmed in several subsequent prospective or cross-sectional studies (40 -44). Foresti et al (43) found positive thyroid autoantibody tests at low titer in only 2 of 23 amiodaronetreated patients, a figure not different from that found in patients receiving other antiarrhythmic drugs. Foresti et al (43) found positive thyroid autoantibody tests at low titer in only 2 of 23 amiodaronetreated patients, a figure not different from that found in patients receiving other antiarrhythmic drugs.…”