Short-Term effects of amiodarone on thyroid function on Aegean region population of Turkey: A prospective regional and observational study

Objective: We aimed to investigate short term effects of oral and infusion dosages of amiodarone on thyroid function. Methods: A hundred and fifty-five prospectively consecutive patients with a diagnosis of atrial or ventricular arrhythmias admitted to our clinic whom amiodarone were applied enrolled to our study. 134 patients received 16 mg/kg amiodarone iv infusion for 24 hours and oral 500±100 mg/day amiodarone as the maintenance dose for one month. 21 patients received only oral 500±100 mg/day amiodarone dose for one month. Follow up visit was performed in the first month of amiodarone therapy. Results: In this study 68% of patients were male and the average age of the patients was 62.8±13.5. The indications for amiodarone treatment were atrial fibrillation (41%), ventricular tachycardia (41%), and preoperative (5%), supraventricular tachycardia (5%), atrial flutter (5%), and ventricular fibrillation (3%). At the first month of follow up 83% of patients were in euthyroid state, 17% of the patients had amiodarone induced thyroid dysfunction (TD), 5% of patients had subclinical hyperthyroidism, 5% of patients had manifest hypothyroidism, 7% of patients had subclinical hyperthyroidism, and 1% of the patients developed overt hyperthyroidism. Conclusion: In this study we showed that amiodarone can cause adverse effects on thyroid function in a short time of period. For this reason patients should be followed in the first, third, sixth and twelfth months of amiodarone therapy and thyroid function should be evaluated.