This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.V.S, Subject name: Pharmacology
The therapeutic efficacy of antihypertensive drugs is blunted by NSAIDs because they: 
Select and explain. 
A. Cause sodium excretion, B. Increase the clearance of antihypertensive drugs, C. Decrease the absorption of antihypertensive drugs, D. Decrease the synthesis of vascular prostacyclin
D: Decrease the synthesis of vascular prostacyclin
Answer: D: Decrease the synthesis of vascular prostacyclin 
Explanation: Ans. (D) Decrease the synthesis of vascular prostacyclins(Ref: KDT 8th/e p215)*PGE2 and PGI2 cause renal vasodilation, natriuresis and increased water clearance due to inhibition of the action of ADH.*Loop diuretics act partly by increasing the stimulation of COX; therefore NSAIDs attenuate the diuretic action of these drugs.