amiodarone and thyroid

Amiodarone is a potent antiarrhythmic drug associated with thyroid dysfunction. Because of the high iodine content of amiodarone the thyroid gland is effectively saturated thus.

Figure 2 Thyroid Disorders Thyroid Function Tests Thyroid

Amiodarone-induced thyroid dysfunction occurs because of both its iodine content and the direct toxic effects of the compound on thyroid parenchyma.

. Amiodarone causes thyroid dysfunction by virtue of the high iodine content. Effects of amiodarone in euthyroid patients. Affiliation 1 Department of Endocrinology and Metabolism Academic Medical Center University of Amsterdam The Netherlands. Amiodarone and thyroid Best Pract Res Clin Endocrinol Metab.

Most patients remain euthyroid. The effects of amiodarone on thyroid hormone economy are at least partially due to interference with the iodothyronine deiodinases which metabolize thyroid hormones. Amiodarones effects on thyroid function can be divided into those effects that are intrinsic drug properties and those effects that are due to iodine 3536. Amiodarone is a benzofuran compound Figure 1 that contains approximately 37 iodine by weight and bears a remarkable structural resemblance to thyroid hormones Figure 1a c Rao et al.

Treatment with amiodarone is associated with changes in thyroid function tests but also with thyroid dysfunction amiodarone-induced hypothyroidism AIH and amiodarone-induced thyrotoxicosis AIT. Thyroid uptake measurements I-123 or I-131 which are used to differentiate causes of hyperthyroidism are generally unreliable in patients who have been taking amiodarone. The synthetic pathways of thyroxine T 4 and triiodothyronine T 3 along with the sites of action of antithyroid drugs are summarised in fig 2The expected effects of amiodarone treatment on individual biochemical parameters of thyroid function are outlined below and summarised in table 1 along with a simplified. The problem with Amiodarone is that it contains a relatively large concentration of iodine.

Amiodarone-induced thyrotoxicosis AIT or amiodarone-induced hypothyroidism AIH may occur depending on the iodine st. However a meta-analysis suggested that with the lower doses of amiodarone 150-330 mg incidence of thyroid dysfunction is 37. Amiodarone is one of the most widely used anti arrhythmic drug. Patients using amiodarone can exhibit symptoms of thyroid dysfunction years after commencing therapy.

Its high iodine content causes inhibition of 5-deiodinase activity. Normal thyroid physiology. Thyroid abnormalities have been noted in up to 14-18 of patients receiving long-term amiodarone therapy. Unfortunately when amiodarone is given to a euthyroid normal thyroid function patient the normal physiologic process for the formation of the thyroid hormones thyroxine T4 and 353-triiodothyronine T3 can be adversely affected.

The effects of amiodarone on the thyroid can be seen as early as a few weeks after starting treatment andor up to several months after its discontinuation. Hypothyroidism occurs in iodine sufficient areas and hyperthyroidism occurs in iodine deficient areas. Although amiodarone is regarded as a highly effective anti-arrhythmic agent its use may lead to alterations in thyroid gland function andor thyroid hormone metabolism partly because of its rich iodine content. In fact approximately 37 of this drug consists of iodine.

Patients treated with amiodarone may manifest altered thyroid hormone profile without thyroid dysfunction or they may present with clinically significant amiodarone-induced. However amiodarone is associated with a number of side effects including thyroid dysfunction both hypo- and hyperthyroidism which is due to amiodarones high iodine. Authors Silvia A Eskes 1 Wilmar M Wiersinga. Pharmacology and pharmacokinetics of amiodarone.

The effects of amiodarone on thyroid hormone economy are at least partially due to interference with the iodothyronine deiodinases which metabolize thyroid hormones. Both AIH and AIT may develop in apparently normal thyroid glands or in the presence of underlying thyroid abnormalities. It often causes changes in thyroid function tests typically an increase in serum T 4 and rT 3 and a decrease in serum T 3 concentrations mainly related to the inhibition of. Additionally the chemical structure of Amiodarone is similar to the structure of T4 or thyroxine which.

Amiodarone a class III antiarrhythmic drug has multiple effects on myocardial depolarization and repolarization that make it an extremely effective antiarrhythmic drug. 1986Therefore a patient taking a standard 200 mg daily dose of amiodarone ingests 75 mg of organic iodine each day. Amiodarone a benzofuranic iodine-rich antiarrhythmic drug causes thyroid dysfunction in 15-20 of cases. In this video youll find out how amiodarone affects thyroid function when this effect stabilizes and how often you should monitor the lab results of patients using amiodarone.

Amiodarone can cause both hypothyroidism AIH amiodarone-induced hypothyroidism and thyrotoxicosis AIT amiodarone-induced thyrotoxicosis. Amiodarone-induced hyperthyroidism is more common in iodine-deficient regions of the world whereas amiodarone-induced hypothyroidism is usually seen in iodine-sufficient areas. It is well known that amiodarone can induce both hypothyroidism and hyperthyroidism due to. Amiodarones effects on thyroid function can be divided into those effects that are intrinsic drug properties and those effects that are due to iodine 3536.

Amiodarone is a benzofuranic-derivative iodine-rich drug widely used for the treatment of tachyarrhythmias and to a lesser extent of ischemic heart disease. Amiodarone and its metabolites demonstrate direct toxicity to cultured thyroid cells exposed to media with concentrations above those normally found in patients. Amiodarone Cordarone is a commonly prescribed medication for the management of both atrial and ventricular arrhythmias.

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