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The Antihypertensive Diet Guide caet.net | Antihypertensive Drugs for Migraine headachedrugs.com | Took antihypertensive medications - don't have hypertension... doctorslounge.com | Drug Index by Category - Antihypertensive-Agents druglib.com |
 The antihypertensives are a class of drugs that are used to treat hypertension (high blood pressure).[1] Evidence suggests that reduction of the blood pressure by 5–6 mmHg can decrease the risk of stroke by 40%, of coronary heart disease by 15–20%, and reduce the likelihood of dementia, heart failure, and mortality from cardiovascular disease. There are many classes of antihypertensives, which lower blood pressure by different means; among the most important and most widely used are the thiazide diuretics, the ACE inhibitors, the calcium channel blockers, the beta blockers, and the angiotensin II receptor antagonists or ARBs. Which type of medication to use initially for hypertension has been the subject of several large studies and resulting national guidelines. The fundamental goal of treatment should be the prevention of the important endpoints of hypertension, such as heart attack, stroke and heart failure. The several classes of antihypertensives differ in side effect profiles, ability to prevent endpoints, and cost. The choice of more expensive agents, where cheaper ones would be equally effective, may have negative impacts on national healthcare budgets.[2] As of 2009, the best available evidence favors the thiazide diuretics as the first-line treatment of choice for high blood pressure when drugs are necessary.[3]
[edit] Available agents[edit] Diuretics Diuretics help the kidneys eliminate excess salt and water from the body's tissues and blood.
Only the thiazide and thiazide-like diuretics have good evidence of beneficial effects on important endpoints of hypertension, and hence, should usually be the 1st choice when selecting a diuretic to treat hypertension. The reason why thiazides-type diuretics are better than the others is (at least in part) thought to be because of their vasodilating properties.[citation needed] Although the diuretic effect of thiazides may be apparent shortly after administration, it takes longer (weeks of treatment) for the full anti-hypertensive effect to develop. In the United States, the JNC7 (The Seventh Report of the Joint National Committee on Prevention of Detection, Evaluation and Treatment of High Blood Pressure) recommends starting with a thiazide diuretic if single therapy is being initiated and another medication is not indicated.[4] This is based on a slightly better outcome for chlortalidone in the ALLHAT study versus other anti-hypertensives and because thiazide diuretics are relatively cheap.[5] A subsequent smaller study (ANBP2) published after the JNC7 did not show this small difference in outcome and actually showed a slightly better outcome for ACE-inhibitors in older male patients.[6] Despite thiazides being cheap, effective, and recommended as the best first-line drug for hypertension by many experts, they are not prescribed as often as some newer drugs. Arguably, this is because they are off-patent and thus rarely promoted by the drug industry.[7] [edit] Adrenergic receptor antagonists
Although beta blockers lower blood pressure, they do not have as positive a benefit on endpoints as some other antihypertensives.[8] In particular, atenolol seems to be less useful in hypertension than several other agents.[9] They do, however, have an important role in the prevention of heart attacks in people who have already had a heart attack.[10] In the United Kingdom, the June 2006 "Hypertension: Management of Hypertension in Adults in Primary Care"[11] guideline of the National Institute for Health and Clinical Excellence, downgraded the role of beta-blockers due to their risk of provoking type 2 diabetes.[12] Despite lowering blood pressure, alpha blockers have significantly poorer endpoint outcomes than other antihypertensives, and are no longer recommended as a first-line choice in the treatment of hypertension.[13] However, they may be useful for some men with symptoms of prostate disease. [edit] Adrenergic receptor agonists[edit] Calcium channel blockersCalcium channel blockers block the entry of calcium into muscle cells in artery walls.
[edit] ACE inhibitors ACE inhibitors inhibit the activity of Angiotensin-converting enzyme (ACE), an enzyme responsible for the conversion of angiotensin I into angiotensin II, a potent vasoconstrictor. [edit] Angiotensin II receptor antagonists Angiotensin II receptor antagonists work by antagonizing the activation of angiotensin receptors. [edit] Aldosterone antagonistsAldosterone receptor antagonists: Aldosterone antagonists are not recommended as first-line agents for blood pressure,[4] but spironolactone and eplerenone are both used in the treatment of heart failure. [edit] VasodilatorsVasodilators act directly on the smooth muscle of arteries to relax their walls so blood can move more easily through them; they are only used in hypertensive emergencies or when other drugs have failed, and even so are rarely given alone. Sodium nitroprusside, a very potent, short-acting vasodilator, is most commonly used for the quick, temporary reduction of blood pressure in emergencies (such as malignant hypertension or aortic dissection).[14][15] Hydralazine and its derivatives are also used in the treatment of severe hypertension, although they should be avoided in emergencies.[15] They are no longer indicated as first-line therapy for high blood pressure due to side effects and safety concerns, but hydralazine remains a drug of choice in gestational hypertension.[14] [edit] Centrally acting adrenergic drugsCentral alpha agonists lower blood pressure by stimulating alpha-receptors in the brain which open peripheral arteries easing blood flow. Central alpha agonists, such as clonidine, are usually prescribed when all other anti-hypertensive medications have failed. For treating hypertension, these drugs are usually administered in combination with a diuretic. Adverse effects of this class of drugs include sedation, drying of the nasal mucosa and rebound hypertension. Some adrenergic neuron blockers are used for the most resistant forms of hypertension: [edit] Future treatment options[edit] Blood pressure vaccineBlood pressure vaccinations are being trialed and may become a treatment option for high blood pressure in the future. Research on the vaccine CYT006-AngQb published in The Lancet on the 8 March 2008 titled, “Vaccination against high blood pressure: a new strategy” showed patients experienced a drop in systolic and diastolic blood pressure after taking the vaccine. Effective blood pressure vaccines would assist those people who forget to take their medication. It would also help those who stop taking their medication due to side effects or falsely believing they don't need them anymore once their blood pressure is lowered.[16] [edit] ChoiceThe choice between the drugs is to a large degree determined by the characteristics of the patient being prescribed for, the drugs' side-effects, and cost. For example, asthmatics have been reported to have worsening symptoms when using beta blockers. Most drugs have other uses; sometimes the presence of other symptoms can warrant the use of one particular antihypertensive (such as beta blockers in case of tremor and nervousness, and alpha blockers in case of benign prostatic hyperplasia). The JNC 7 report outlines compelling reasons to choose one drug over the others for certain individual patients.[4] [edit] See also[edit] References
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