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: Surgery
[{'content': 'Ursodeoxycholic acid is a : \nSelect and explain. \nA. Urinary stone dissolving drug, B. Thrombolytic drug, C. Gall stone dissolving drug, D. Antifibrinolytic', 'role': 'user'}, {'content': 'Answer: C \nExplanation: • Medical therapy for gallstones utilizes bile acids: Chenodeoxycholic acid (CDCA) and Ursodeoxycholic acid (UDCA)\nMechanism of Action\n• They inhibit HMG-CoA reductase, the rate limiting enzyme for cholesterol synthesis, thus decreases cholesterol saturation of bile\n• They cause dispersion of the cholesterol from the stones by physico-chemical means', 'role': 'assistant'}]