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Many Medications Can Affect Thyroid Function | |
| By DR. MANFRED BLUM New York University Medical Center For AP Special Features Many medications can adversely affect thyroid function. The increasing use of dietary supplements and medications containing iodine has placed many Americans at risk of problems caused by abnormal thyroid gland function. Iodine is essential for production of thyroid hormone, which governs many essential body functions. At the turn of the century, inadequate diets were often responsible for thyroid problems - low function and goiter (thyroid enlargement), caused by lack of iodine in the diet. These days, when a better diet and measures such as iodization of salt ensure adequate iodine intake for virtually all Americans, the problem is often a thyroid made overactive by excessive iodine intake. Iodine supplements are readily available in health food stores, which tout them as panaceas for a number of conditions. In addition, many medications contain high concentrations of iodine. They include expectorants, used to treat asthma and bronchitis, and amiodarone, given for heart arrhythymias. Iodine is also present in antiseptics. The risk of an overactive thyroid caused by excess iodine intake is greatest for persons in whom the thyroid's normal mechanism for coping with excess iodine is out of order. Symptoms of an overactive thyroid include nervousness, overactivity, increased sweating, palpitations, fatigue, increased appetite and insomnia. Some people face the opposite risk from excess iodine - reduction of thyroid hormone production. They include some individuals who have a common thyroid illness called Hashimoto's thyroiditis and some people are being treated for a psychiatric problem with lithium carbonate. Symptoms of an underactive thyroid include sluggishness and enlargement of the gland. In addition, people who are being treated for an underactive thyroid gland with hormone tablets need to be aware that some other drugs can reduce the absorption of their thyroid medication. Agents that interfere with thyroid absorption include iron, cholestyramine, sucralfate and antacids containing aluminum hydroxide. These drugs should not be taken together with thyroid hormone. It is best to allow an interval of several hours after taking thyroid medications and to take the hormone on an empty stomach. --- Dr. Manfred Blum is Professor in Clinical Medicine at New York University School of Medicine. Copyright 1996 Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed. | |