This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Other topics and Adverse effects, Subject name: Anatomy
[{'content': 'Concomitant administration of this drug with organic nitrates is contraindicated due to marked potentiation of vasodilatory action leading to profund hypotension. This drug is: \nSelect and explain. \nA. Propanolol, B. Fluoxetine, C. Hydrochlorothiazide, D. Sildenafil', 'role': 'user'}, {'content': 'Answer: D \nExplanation: (Ref: KDT 6/e p525) Nitrates release No, that acts by increasing cGMP. Phosphodiesterase inhibitors like sildenafil inhibits the breakdown of cGMP. Concomitant use of these two drugs may result in profound hypotension.', 'role': 'assistant'}]