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': 'Alprostadil is not used for treatment of: \nSelect and explain. \nA. Erectile dysfunction, B. Pulmonary hypertension, C. Patent ductus arteriosus, D. Critical limb ischemia', 'role': 'user'}, {'content': "Answer: C \nExplanation: To maintain patency of ductus arteriosus in neonates with congenital heart defects, till corrective surgery is undertaken, PGE1 (Alprostadil) is used.\nImpotence: Alprostadil (PGE1) injected into the penis causes erection lasting 1-2 hours. However, oral sildenafil / tadalafil is now preferred for erectile dysfunction.\xa0\nPeripheral vascular diseases: PGI2 (or PGE1) infused i.v. can relieve rest pain and promote healing of ischaemic ulcers in severe cases of intermittent claudication and in Raynaud's disease.\nPulmonary hypertension: PGI2 lowers pulmonary artery resistance. Accordingly, few cases of primary pulmonary hypertension have been successfully maintained on epoprostenol infused continuously in a large vein.\nlndomethacin\xa0 has been the most common drug used for medical closure of patent ductus arteriosus.\n\nReference: Essentials of Medical Pharmacology Eighth Edition KD\xa0TRIPATHI\xa0page no 207,219", 'role': 'assistant'}]