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': 'The following drugs may be used in erectile dysfunction, EXCEPT: \nSelect and explain. \nA. Phenylephrine, B. Apomorphine, C. Alprostidil, D. PGE1 analogues', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Medications like Phentolamine, Papavarine hydrochloride and Alprostidil (PGE1 analogue) PGE1 analogues are given as intra-cavernosal injections in the treatment of erectile dysfunction. Phenylephrine is a selective alpha agonist which is used to reverse the erections of intra-thecal injections. It cannot be used in the treatment of erectile dysfunction. Ref: Clinical Manual of Sexual Disorders By Richard Balon, R. Taylor Segraves, Pages 230-35; Contemporary Issues in Prostate Cancer By Jeanne Held-Warmkessel, Pages 338-41; Erectile Dysfunction: Current Investigation and Management By Ian Eardley, Krishna Sethia, Pages 55, 101; K D Tripathi Textbook of Pharmacology, 5th Edition', 'role': 'assistant'}]