LONG-TERM AMIODARONE THERAPY AND ANTITHYROID ANTIBODIES

Amiodarone is a benzofuran antiarrhythmic drug widely used in Europe and South America, and also approved for use for ventricular arrhythmias in the United States. Each amiodarone tablet (200 mg) contains 75 mg of iodine, which can induce hyperthyroidism and, more frequently, hypothyroidism in long-term therapy; this requires periodic monitoring of thyroid function in order to detect subclinical disorders. It has been suggested that an additional mechanism of thyroid disease could be immunologic disorders induced by the amiodarone itself1,2; the presence of antithyroid antibodies are even an early marker for thyroid disease,1 but this has not been been confirmed by other studies3,4 using different antibody detection methods. To clarify the different results, we prospectively studied the presence of antithyroid antibodies in patients before and during long-term administration of amiodarone, both by indirect immunofluorescence (used in the studies in which a high percentage of positive cases was detected) and by immunohemagglutination methods. © 1992.