A number of drug classes are effective for initial and subsequent management of hypertension:
Alpha-2-agonists (eg, methyldopa, clonidine, guanabenz, guanfacine) stimulate alpha-2-adrenergic receptors in the brain stem and reduce sympathetic nervous activity, lowering blood pressure (BP). Because they have a central action, they are more likely than other antihypertensives to cause drowsiness, lethargy, and depression; they are no longer widely used. Clonidine can be applied transdermally once a week as a patch; thus, it may be useful for nonadherent patients (eg, those with dementia).
Postsynaptic alpha-1-blockers (eg, prazosin, terazosin, doxazosin) are no longer used for primary treatment of hypertension because evidence suggests no reduction in mortality. Also, doxazosin used alone or with antihypertensives other than diuretics increases risk of heart failure. However, they may be used in patients who have prostatic hypertrophy and need a 4th antihypertensive or in people with high sympathetic tone (ie, with high heart rate and spiking blood pressures) already on the maximum dose of a beta-blocker.
A dry, irritating cough is the most common adverse effect, but
angioedema
Angioedema Angioedema is edema of the deep dermis and subcutaneous tissues. It is usually an acute but sometimes a chronic mast cell–mediated reaction caused by exposure to a drug (eg, angiotensin-converting... read more
Thiazide-type diuretics enhance the antihypertensive activity of ACE inhibitors more than that of other classes of antihypertensives. Spironolactone and eplerenone also appear to enhance the effect of ACE inhibitors.
Beta-blockers (see table
Oral Beta-Blockers for Hypertension
Oral Beta-Blockers for Hypertension
Beta-blockers with intrinsic sympathomimetic activity (eg, acebutolol, pindolol) do not adversely affect serum lipids; they are less likely to cause severe bradycardia.
Long-acting nifedipine, verapamil, or diltiazem is used to treat hypertension, but short-acting nifedipine and diltiazem are associated with a high rate of myocardial infarction and are not recommended.
Aliskiren, a direct renin inhibitor, is used in the management of hypertension. Dosage is 150 to 300 mg orally once a day, with a starting dose of 150 mg.
Direct vasodilators, including minoxidil and hydralazine (see table
Direct Vasodilators for Hypertension
Direct Vasodilators for Hypertension
Loop diuretics
Potassium-sparing diuretics
Thiazide-type diuretics
Diuretics modestly reduce plasma volume and reduce vascular resistance, possibly via shifts in sodium from intracellular to extracellular loci.
Loop diuretics are used to treat hypertension only in patients who have lost > 50% of kidney function; these diuretics are given at least twice a day (except for torsemide which can be given once a day).
Thiazide-type diuretics are most commonly used. In addition to other antihypertensive effects, they cause a small amount of vasodilation as long as intravascular volume is normal. All thiazides are equally effective in equivalent doses; however, thiazide-type diuretics have longer
half-lives and are relatively more effective at similar doses. Thiazide-type diuretics can increase serum cholesterol slightly (mostly low-density lipoprotein) and also increase triglyceride levels, although these effects may not persist > 1 year. Furthermore, levels seem to increase in only a few patients. The increase is apparent within 4 weeks of treatment and can be ameliorated by a low-fat diet. The possibility of a slight increase in lipid levels does not contraindicate
diuretic use in patients with dyslipidemia
Dyslipidemia Dyslipidemia is elevation of plasma cholesterol, triglycerides (TGs), or both, or a low high-density lipoprotein cholesterol level that contributes to the development of atherosclerosis... read more
All diuretics except the potassium-sparing distal tubular diuretics cause significant potassium loss, so serum potassium is measured monthly until the level stabilizes. Unless serum potassium is normalized, potassium channels in the arterial walls close and the
resulting vasoconstriction makes achieving the blood pressure (BP) goal difficult. Patients with potassium levels < 3.5 mEq/L (< 3.5 mmol/L) are given potassium supplements. Supplements may be continued long-term at a lower dose, or a potassium-sparing diuretic (eg, daily spironolactone 25 to 100 mg, triamterene 50 to 150 mg, amiloride 5 to 10 mg) may be added. Potassium supplements or addition of a potassium-sparing diuretic is also
recommended for any patients who are also taking digitalis, have a known heart disorder, have an abnormal ECG, have ectopy or arrhythmias
Overview of Arrhythmias The normal heart beats in a regular, coordinated way because electrical impulses generated and spread by myocytes with unique electrical properties trigger a sequence of organized myocardial... read more
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