Men are at increased risk of amiodarone-associated thyrotoxicosis in the UK.
Sir,

Amiodarone is associated with both thyrotoxicosis and hypothyroidism.1 Previous estimates of the frequency of thyroid problems in amiodarone users have been based on small numbers of patients or hospital clinic populations. They range from 1% to 23% for thyrotoxicosis and from 1% to 32% for hypothyroidism.2 Amiodarone-associated thyrotoxicosis (AAT) seems commoner in men.3,,4 This could reflect a bias toward greater use of amiodarone by males, who are at increased risk of cardiovascular disease.

In South Worcestershire, all chronic prescribing of amiodarone is done in primary care. The BNF guideline of 6-monthly thyroid function testing in such patients is recommended. We estimated the frequency of amiodarone-associated thyroid disease by examining the occurrence of both AAT and amiodarone-associated hypothyroidism (AAH) in …