<prompt> The therapeutic efficacy of antihypeensive drug is blunted by NSAIDs because they:Cause sodium excretionIncrease the clearance of antihypeensive drugsDecrease the absorption of antihypeensive drugsDecrease the synthesis of vascular prostacyclin  <response>: Ans. is d i.e., Decrease the synthesis of vascular prostacyclin o NSA IDs blunt the antihypeensive effect of diuretics. o Loop diuretics act paly intrarenal hemodynamics by increasing the synthesis of prostaglandins by stimulation of COX o Prostaglandins especially PGE2 and PGI2 cause renal vasodilation, natriuresis and increased water clearance due to inhibition of the ADH action. o NSAIDs inhibit the synthesis of prostaglandins by inhibiting COX. Therefore, NSAIDs blunt the diuretic effect of loop diuretics. 