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What is the reaction mechnism of lisinopril?

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suzanne66 18 Sep 2011

Lisinopril belongs to a class of drugs called ACE inhibitors.

ACE inhibitors produce vasodilation by inhibiting the formation of angiotensin II. This vasoconstrictor is formed by the proteolytic action of renin (released by the kidneys) acting on circulating angiotensinogen to form angiotensin I. Angiotensin I is then converted to angiotensin II by angiotensin converting enzyme.

ACE also breaks down bradykinin (a vasodilator substance). Therefore, ACE inhibitors, by blocking the breakdown of bradykinin, increase bradykinin levels, which can contribute to the vasodilator action of ACE inhibitors.

Angiotensin II constricts arteries and veins by binding to AT1 receptors located on the smooth muscle, which are coupled to a Gq-protein and the the IP3 signal transduction pathway. Angiotensin II also facilitates the release of norepinephrine from sympathetic adrenergic nerves and inhibits norepinephrine reuptake by these nerves. This effect of angiotensin II augments sympathetic activity on the heart and blood vessels.

ACE inhibitors have the following actions:

Dilate arteries and veins by blocking angiotensin II formation and inhibiting bradykinin metabolism. This vasodilation reduces arterial pressure, preload and afterload on the heart.
Down regulate sympathetic adrenergic activity by blocking the facilitating effects of angiotensin II on sympathetic nerve release and reuptake of norepinephrine.
Promote renal excretion of sodium and water (natriuretic and diuretic effects) by blocking the effects of angiotensin II in the kidney and by blocking angiotensin II stimulation of aldosterone secretion. This reduces blood volume, venous pressure and arterial pressure.
Inhibit cardiac and vascular remodeling associated with chronic hypertension, heart failure, and myocardial infarction.
Elevated plasma renin is not required for the actions of ACE inhibitors, although ACE inhibitors are more efficacious when circulating levels of renin are elevated. We know that renin-angiotensin system is found in many tissues, including heart, brain, vascular and renal tissues. Therefore, ACE inhibitors may act at these sites in addition to blocking the conversion of angiotensin in the circulating plasma.

rvnew 20 Sep 2011

So what about the long term use of this drug. I'm on 20mg lisinopril with a 12.5 dieuretic once a day. I wonder is this drug doing me some type of harm in the long run even though it's doing me good for now? I would like to not have to be on it but I don't know about any "natural cures" at least not any that don't seem to involve a lot of hassels and/or expense. Thanks for you comments.

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