This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Pharmacology
[{'content': 'Which of the following is not used in the treatment of pulmonary hypeension? \nSelect and explain. \nA. Calcium channel blockers, B. Alpha blockers, C. Prostacyclins, D. Endothelin receptor antagonists', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Alpha blocker like prazosin, doxazosin, tamsulosin have no role in pulmonary hypeension Prostacyclin I2 analogs, endothelin antagonists like macicentan are used in pul.HTN CCBs- cause vasodilation thereby providing benefit in Pul. HTN sildenafil, tadalafil- PDE5 inhibitors are also used Ref: KD Tripathi 8th ed', 'role': 'assistant'}]