ACE inhibitors
ANGIOTENSIN CONVERTING ENZYME INHIBITORS
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ACE inhibitors like teprotide, captopril, enalapril, Lisinopril, Perindopril, Rampiril
Teprotide - synthesized from bradykinin potentiating factor found in pit viper venom was the first ACE inhibitor which is a nanopeptide with brief duration of action.
Captopril- Orally active dipeptide analogue is a prototype of ACE inhibitor.
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Abolishes pressor action of Angiotensin I but not Angiotensin II.
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Increase plasma kinin levels and potentiate the hypotensive action of bradykinin.
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Elevated kinins and prostaglandins may be responsible for cough induced by ACE inhibitors.
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Interferes with degradation of substance P.
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The lowering of blood pressure depends on sodium ion status and renin angiotensin activity.
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The hypotension is due to decrease of total peripheral resistance.
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Both systolic and diastolic blood pressure falls
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Renal, cerebral and coronary blood flow is not compromised
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70% of orally administered drug is absorbed.
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Food reduces the bioavailability
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Partly metabolized and excreted unchanged in urine.
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Poorly crosses blood brain barrier.
Adverse Effects
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Usually well tolerated
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Occasionally hypotension,hyperkalaemia,cough,allergy,angiodema,dysguesia,foetal abnormalities, nausea, bowel upset, granulocytopenia,proteinuria, acute renal failure may occur.
Drug interactions
Enalapril
Advantages
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More potent than captopril.
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Food does not affect absorption.
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Onset of action is slower.
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Longer duration of action
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Lisinopril
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Lysine derivative of enalaprilat.
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Absorbed orally slowly
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Food does not interfere with its absorption
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Duration of action is longer permitting single daily dosing
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Uniform hypotensive action.
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Minimal side effects with reduction in venous return, cardiac contractility and cardiac output.
Perindopril
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Long acting ACE inhibitor.
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Slow onset of action.
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Undergoes extensive metabolism.
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Tends to restore the reduced elastic properties of arteries and heart in hypertensive.
Ramipril
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Last modified: Tuesday, 15 May 2012, 10:40 AM