Untreated high blood pressure (pressure within the arteries) leads to major organ damage. According to the American Heart Association, possible complications of high blood pressure (HBP) include heart disease, such as angina, heart attacks and congestive cardiac failure; stroke; kidney disease; vision loss; erectile dysfunction; memory loss; and fluid in the lungs. The Centers for Disease Control and Prevention estimates that about one in three U.S. adults has high blood pressure (also known as hypertension) and that untreated high blood pressure is involved in about 300,000 deaths in the U.S. each year.
Drug treatment of high blood pressure involves single or combined agents. These anti-hypertensive (blood pressure lowering) drugs belong to a wide variety of classes.
Diuretics
Diuretics act on the kidney to remove water and salt, reducing blood volume. According to the Mayo Clinic, they are usually the first type of drug to be prescribed, often in combination with other agents. Drugs in this class include chlorthalidone (Hygroton), chlorothiazide (Diuril), hydrochlorothiazide or HCTZ (Hydrodiuril, Esidrix, Microzide), furosemide (Lasix), indapamide (Lozol), metolazone (Zaroxolyn, Mykrox), amiloride hydrochloride (Midamar), spironolactone (Aldactone), triamterene (Dyrenium) and bumetanide (Bumex).
There are also fixed dose combinations of the diuretics. These include Moduretic (amiloride and HCTZ), Aldactazide (spironolactone and HCTZ), Dyazide and Maxzide (triamterene and HCTZ).
Beta Blockers
These act on certain receptors of the nervous system to slow the heart rate and open the blood vessels, reducing the workload on the heart. They do not appear to work well alone in blacks, according to the Mayo Clinic. They are more effective when combined with diuretics.
Drugs in this class include acebutolol (Sectral), propranolol (Inderal), pindolol (Visken), timolol (Blocadren), atenolol (Tenormin), carvedilol (Coreg), bisoprolol (Zebeta), esmolol (Brevibloc), metoprolol (Toprol, Lopressor), sotalol (Betapace), penbutolol (Levatol), nadolol (Corgard), carteolol (Cartrol) and betaxolol (Kerlone).
Angiotensin Converting Enzyme (ACE) Inhibitors
Angiotensin is a naturally occurring chemical that causes widespread narrowing of blood vessels and raises blood pressure. ACE inhibitors block the formation of angiotensin, indirectly reducing blood pressure. According to the Mayo Clinic, they are preferred in coronary artery disease, congestive cardiac failure and kidney disease.
Drugs in this class include benazepril (Lotensin), captopril (Capoten), enalapril (Vasotec), fosinopril (Monopril), lisinopril (Zestril, Prinivil), moexipril (Univasc), perindopril (Aceon), quinapril (Accupril), ramipril (Altace) and trandolapril (Mavik).
Angiotensin II Receptor Blockers (ARBs)
These reduce blood pressure by blocking the released angiotensin from exerting its usual hypertensive effects. They are also useful in the same types of patients as ACE inhibitors. The American Heart Association warns that ARBs and ACE inhibitors should not be used in pregnancy.
ARBs include candesartan (Atacand), eprosartan mesylate (Teveten), irbesartan (Avapro), losartan (Cozaar), telmisartan (Micardis) and valsartan (Diovan).
Calcium Channel Blockers (CCBs)
The presence of calcium ions in the muscles of the heart and blood vessels makes them contract more forcefully, increasing the strength of contraction in the heart and narrowing the arteries. CCBs reduce blood pressure by blocking the entry of calcium ions into these muscles.
CCBs include amlodipine (Norvasc), nifedipine (Adalat, Procardia), isradipine (DynaCirc), felodipine (Plendil), nisoldipine (Sular), diltiazem (Tiazac, Cardizem, Dilacor), verapamil (Calan, Covera, Verelan, Isoptin), nicardipine (Cardene) and bepridil (Vasocor).
Alpha Blockers
These act on certain nerve terminals to dilate the arteries. They include doxazosin (Cardura), prazosin (Minipress) and terazosin (Hytrin).
Combined Alpha and Beta Blockers
Some single agents act on two kinds of nerve terminals to exert their anti-hypertensive effects. These combined receptor blockers, according to the AHA, are very useful in hypertensive crises and in hypertensive patients in danger of congestive cardiac failure.
Drugs in this class include carvedilol (Coreg), labetalol (Normodyne, Trandate).
Centrally Acting Agents
These agents act on components in the brain and spinal cord to relax the muscles in the arteries and dilate the blood vessels. They include alpha methyldopa (Aldomet), clonidine (Catapres), guanabenz (Wytensin), guanfacine (Tenex), reserpine (Serpasil), guanethidine (Ismelin) and guanadrel (Hylorel).
Vasodilators
These act directly on the smooth muscles of the arteries to dilate them. They are minoxidil (Loniten) and hydralazine (Apresoline).
Combined Agents
Anti-hypertensives also come in combinations of agents from the different classes in a single tablet. Diuretics and beta blockers are combined in drugs like Tenoretic (atenolol and chlorthalidone), Corzide (nadolol and bendroflumethiazide) and Lopressor HCT (metoprolol and HCTZ). ACE inhibitors and diuretics are combined in Monopril HCT (fosinopril and HCTZ), Uniretic (moexipril and HCTZ), Vaseretic (enalapril and HCTZ) and Zestoretic (lisinopril and HCTZ). ARBs are combined with diuretics in Hyzaar (losartan and HCTZ) and Micardis HCT (telmisartan and HCTZ). ACE inhibitors are combined with CCBs in Lotrel (amlodipine and benazepril) and Tarka (trandolapril and verapamil).
