The effect of propranolol on thyroid hormones and oxygen consumption in thyrotoxicosis.

The possibility that propranolol may exert its beneficial actions in thyrotoxicosis by an effect on thyroid hormone concentrations has been investigated by measuring these and oxygen consumption in a group of thyrotoxic patients before and after treatment with propranolol. Following treatment a significant fall in plasma T3 concentration and oxygen consumption occurred and a direct correlation was found between these two variables. Propranolol may, therefore, exert some of its beneficial effects in thyrotoxicosis by an action on T3 metabolism.