This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
[{'content': 'Fastest acting antithyroid drugs ? \nSelect and explain. \nA. Iodides of Na/ K, B. Propylthiuracil, C. Methimazole, D. Nitrates', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Iodides of Na Iodine and Iodides Iodine is the fastest acting thyroid inhibitor Most impoant action is inhibition of hormone release (thyroid constipation); but all facets of thyroid synthesis may be affected. Excess iodide inhibits its own transpo in thyroid cells and may alter the redox potential of cells, thus interfering iodination - reduced T4/T3 synthesis (Wolff-chaikoff effect).", 'role': 'assistant'}]