Mechanism of action
Exact mechanism of action is unknown. It inhibits hormone release. It is fastest acting thyroid inhibitor. On regular administration, peak antithyroid effect is seen in two weeks after which thyrotoxicosis may recur.Iodine is the precursor of thyroxine. The radioactive form of iodine is taken up by iodide transporter of the thyroid the same way as natural iodine and is similarly processed. The b particle destroys the follicular cell, gradually leading to volume reduction and control of the thyrotoxicosis.