Angiotensin II, a potent vasoconstrictor,
is produced by the action of angiotensin
converting enzyme (ACE) on the substrate
angiotensin I. Angiotensin II activity produces:
(a) A rapid pressor response,
(b) A slow pressor response and
(c) Vascular and cardiac
hypertrophy and remodeling.
Antihypertensive effects of ACE
inhibitors are due to the reduction in the amount
of angiotensin II produced.
ACE inhibitors are efficacious in
of hypertension and have a
side effect profile
ACE inhibitor are advantageous in
management of diabetic patients by reducing the
development of diabetic neuropathy and
ACE inhibitor are probably the
antihypertensive drug of choice in treatment of
hypertensive patient who have hypertrophic left
inhibitors reduce the normal aldosterone response to sodium loss
(normally aldosterone opposes diuretic-induced sodium loss).
Therefore, the use of ACE
inhibitors enhance the efficacy of diuretic treatment, allowing the
use of lower diuretic dosages and improving control of hypertension
If diuretics are
administered at higher dosages in combination with ACE inhibitors
significant and undesirable hypotensive reactions can occur with
attendant excessive sodium loss.
Reduction in aldosterone production by ACE
inhibitors also affects potassium levels.
is for potassium retention, which may be serious
in patients with renal disease or if the patient
is also taking potassium sparing diuretics,
nonsteroidal anti-inflammatory agents or
although rare, may be potentially fatal.
ACE inhibitiors should not be used during
renovascular hypertension, glomerular
filtration pressures are maintained by
vasoconstriction of the post-glomerular
arterioles, an effect mediated by
Initial dose of an ACE
inhibitor may precipitate an excessive