[Amiodarone and thyroid dysfunction: a pending problem].

Amiodarone is an antiarhytmic drug used in many clinical situations for its probed effect; it is also preferred in particular groups of patients (heart failure, post-ischemical) for its safe and its prognostic benefits. However, a substantial proportion of amiodarone treated patients develop either hypothyroidism or thyrotoxicosis. Both abnormalities may occur in apparently normal glands or in glandes with pre-existed abnormalities. It may be difficult to recognize the dysfunction because of the many changes in thyroid function test results that occur in euthyroid patients who are receiving amiodarone. Hypothyroidism is a well defined clinical situation managable thanks to common guidelines. The occurrence of hypothyroidism does not necessitate withdrawing amiodarone while instituting L-T4 replacement therapy, although many cases are transient and will spontaneously remit after amiodarone withdrawal. At the opposite, hyperthyroidism needs more attention to be diagnosed and to be treated, in fact there is a "personal" clinical-therapeutical behave towards it, caused by the lack of big trials made on this clinical situation. Effective strategies exist for the management of thyroid dysfunction, these should be tailored to the needs of the individual patient.