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': 'Hypothyroidism is caused by which of the following anti-tubercular drug - \nSelect and explain. \nA. PAS, B. Ethionamide, C. Cycloserine, D. Pyrazinamide', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., PAS Adverse effects of para-amino salicylic acid (PAS) --> Anorexia, nausea, epigastric pain, rashes, goiter (hypothyroidism), fever, malaise, liver dysfunction, and blood dyscrasias. Adverse effects of ethionamide :Anorexia, nausea, vomiting, abdominal pain, hepatitis, optic or peripheral neuritis, metal disturbances and blood dyscrasias.", 'role': 'assistant'}]