Drugs used in Hypertension. This left ventricle is very thickened (slightly over 2 cm in thickness), but the rest of the heart is not greatly enlarged. This is typical for hypertensive heart disease. The hypertension creates a greater pressure load on the heart to induce the hypertrophy.
This left ventricle is very thickened (slightly over 2 cm in thickness), but the rest of the heart is not greatly enlarged. This is typical for hypertensive heart disease. The hypertension creates a greater pressure load on the heart to induce the hypertrophy.
The left ventricle is markedly thickened in this patient with severe hypertension that was untreated for many years. The myocardial fibers have undergone hypertrophy.
May cause renal failure in patients with bilateral renal artery stenosis:
- Angiotensin II required to constrict postglomerular arterioles and maintain adequate GF.
- Inhibition of angiotensin II formation does not seriously impair secretion and excessive K+ retention occurs only with K+ supplements or K-sparing diuretics (recall that aldosteroneincr Na+reabsorption and K+ excretion).
[recall that diuretics are used to decr edema in CHF]. But also used in some renal diseases and hepatic cirrhosis.
Can be prevented by giving K supplements, or by combining therapy with K-sparing drugs.
This segment has a high binding capacity for absorbing NaCldiuresis produced at this site is much greater than at other sites.
Act on the luminal membrane where they inhibit the cotransport of Na+/K+/2Cl-.
[Recall that the Na+ is actively transported out of the cells into the interstitium by an Na+/K+-ATPase-dependent pump at the basolateral membrane].
the site of action of
Tubule Cell –
Compelling and possible indications and contrindications for the major classes of antihypertensive drugs
CLASSS OF DRUG
Angiotensin converting enzyme (ACE) inhibitors
Heart failureLeft ventricular dysfunction
Chronic renal disease *Type II diabetic nephropathy
Renal impairment *Peripheral vascular disease †
Angiotensin II receptor antagonists
Cough induced by ACE inhibitor ‡
Heart failureIntolerance of other antihypertensive drugs
Peripheral vascular disease
Heart failureDyslipidaemiaPeripheral vascular disease
Asthma or COPDHeart block
Calcium antagonists (dihydropyridine)
Isolated systolic hypertension (ISH) in elderly patients
Calcium antagonists (rate limiting)
Combination with b-blockade
Heart blockHeart failure
Elderly patients including ISH
* ACE inhibitors may be beneficial in chronic renal failure but should be used with caution. Close supervision and specialist advice are needed when there is established and significant renal impairment† Caution with ACE inhibitors and angiotensin II receptor antagonists in peripheral vascular disease because of association with renovascular disease.‡ If ACE inhibitor indicatedfb-blockers may worsen heart failure, but in specialist hands may be used to treat heart failure