This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Pharmacology
[{'content': 'Fastest acting antithyroid drug is \nSelect and explain. \nA. KI, B. Propylthiouracil, C. Carbimazole, D. Cholestyramine', 'role': 'user'}, {'content': 'Answer: A \nExplanation: KI: It is the fastest acting thyroid inhibitor which inhibits hormone release. it has a direct action on thyroid cells and also attenuates TSH and cyclic AMP induced thyroid stimulation. The gland if enlarged; shrinks, becomes firm and less vascular. The thyroid status returns to normal at a faster rate. So it is used just before thyroid surgeries REF KD tripathi 8th ed', 'role': 'assistant'}]