amiodarone and thyroid

The effects range from abnormal thyroid function test findings to overt thyroid dysfunction which may be. Nattel S Davies M Quantz M 1988 The antiarrhythmic efficacy of amiodarone and desethylamiodarone alone and in combination in.

Pin On Endocrine Nursing School

9 The effect that amiodarone has on thyroid hormone secretion depends on the dose and duration of treatment.

. Thus a comparison between the incidences of thyroid dysfunction in regions with low iodine intake such as. 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 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. It often causes changes in thyroid function tests typically an increase in serum T4 and rT3 and a decrease in serum T3 concentration.

In fact approximately 37 of this drug consists of iodine. This topic will review the major effects of amiodarone on thyroid function. Thyroid function should be checked at least every six months. In this video youll find out how amiodarone affects thyroid function when this effect stabilizes and how often you should monitor.

Patients treated with amiodarone may manifest altered thyroid hormone profile without thyroid dysfunction or they may present with clinically significant. AIH is more prevalent in iodine-sufficient areas while AIT occurs more often in iodine-deficient areas. 8 10 Thus deposits of amiodarone with iodine can take months to be eliminated. Amiodarone causes thyroid dysfunction by virtue of the high iodine content.

The clinical use and other side effects of amiodarone are reviewed elsewhere. Amiodarone works well for what we use it for but it can include the kitchen sink when we begin to list side effects and drug interactions. The problem with Amiodarone is that it contains a relatively large concentration of iodine. 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.

Additionally the chemical structure of Amiodarone is similar to the structure of T4 or thyroxine which is one of the hormones produced by the thyroid gland. Am J Cardiol 58. Pharmacology and pharmacokinetics of amiodarone. However a meta-analysis suggested that with the lower doses of amiodarone 150-330 mg incidence of thyroid dysfunction is 37.

Effects of amiodarone in euthyroid patients. Normal thyroid physiology. Its prevalence is influenced by the environmental iodine supply. In contrast to amiodarone.

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. 9 Usually T 3 levels decrease and T 4 free T 4 and TSH levels increase in the first 3. Amiodarone is dealkylated in the liver to its major active metabolite desethylamiodarone. Amiodarone Cordarone is a commonly prescribed medication for the management of both atrial and ventricular arrhythmias.

Nademanee K Singh BN Hendrickson JA Hershman JM 1986 Amiodarone thyroid hormone indexes and altered thyroid function. Amiodarone has a long half-life up to 100 days because its lipophilic and stored in adipose tissue. Long-term serial effects in patients with cardiac arrhythmias. Patients using amiodarone can exhibit symptoms of thyroid dysfunction years after commencing therapy.

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. The effects of amiodarone on thyroid hormone economy are at least partially due to interference with the iodothyronine deiodinases which metabolize thyroid hormones. It is well known that amiodarone can induce both hypothyroidism and hyperthyroidism due to the iodine. Before starting amiodarone your doctor likely did baseline tests on your thyroid as well as your liver lungs and eyes so that.

Amiodarone is very lipophilic and concentrates in various tissues and organs such as adipose tissue skeletal muscles myocardium liver lung and thyroid. 981986 PubMed Google Scholar. Amiodarone and its metabolites demonstrate direct toxicity to cultured thyroid cells exposed to media with concentrations above those normally found in patients. Amiodarone also causes an anti-thyroid action via WolffChaikoff effect due its large amount of iodine in its molecule which causes a particular cardiac hypothyroidism with bradycardia and arrhythmia.

However amiodarone is associated with a number of side effects including thyroid dysfunction both hypo- and hyperthyroidism which is due to amiodarones high iodine content and its direct toxic effect on the thyroid. Amiodarone-induced thyroid dysfunction varies widely from 15 to 30. One adverse effect actually involves an interference with the thyroid gland. 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.

Thyroid abnormalities have been noted in up to 14-18 of patients receiving long-term amiodarone therapy. Amiodarone therapy is associated with a number of side effects including thyroid dysfunction thyrotoxicosis in 2. Amiodarone-induced hyperthyroidism is more common in iodine-deficient regions of the world whereas amiodarone-induced hypothyroidism is usually seen in iodine-sufficient areas. Hypothyroidism occurs in iodine sufficient areas and hyperthyroidism occurs in iodine deficient areas.

1986Therefore a patient taking a standard 200 mg daily dose of amiodarone ingests 75 mg of organic iodine each day. 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. 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-induced thyroid dysfunction occurs because of both its iodine content and the direct toxic effects of the compound on thyroid parenchyma. Amiodarone is one of the most widely used anti arrhythmic drug.

Pin On Thyroid