<prompt> ACE inhibitors are contraindicated in bilateral renal aery stenosis, because -Angiotensin II has direct effect on GFREnhances bradykinin actionHyperreninism affects renal parenchymaAffects prostaglandins  <response>: Ans. is a i.e., Angiotensin II has direct effect on GFR o Patients with renal aery stenosis are dependent on efferent aeriolar vasoconstiction for maintenance of glomerular filtration pressure. Angiotensin II is responsible for vasoconstriction of efferent aeriole. o ACE inhibitors prevent the generation of Angiotensin II. This causes dilatation of efferent aerioles and fall in glomerular filtration pressure. This can ppt renal failure. o Therefore ACE inhibition are CI in patients with bilateral renal aery stenosis. 