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
All of the following drugs reduce afterload, except: 
Select and explain. 
A. Enalapril, B. Propranolol, C. Hydralazine, D. Sodium nitroprusside
B: Propranolol
Answer: B: Propranolol 
Explanation: Ref:KDT 6/e p504 Afterloadis reduced by the drugs having aerioler dilating propey. Propanolol is a non-selective beta-blocker. It can cause vasoconstriction by antagonizing beta2 mediated vasodilation. It, therefore do not decrease afterload.