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Antihypertensives are a class of drugs that are used to treat hypertension (high blood pressure). Antihypertensive therapy seeks to prevent the complications of high blood pressure, such as stroke and myocardial infarction. Evidence suggests that reduction of the blood pressure by 5 mmHg can decrease the risk of stroke by 34%, of ischaemic heart disease by 21%, 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 drugs are thiazide diuretics, calcium channel blockers, ACE inhibitors, angiotensin II receptor antagonists (ARBs), and beta blockers. 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. Patient age, associated clinical conditions and end-organ damage also play a part in determining dosage and type of medication administered. 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. 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. Although clinical evidence shows calcium channel blockers and thiazide-type diuretics are preferred first-line treatments for most people (from both efficacy and cost points of view), an ACE inhibitor is recommended by NICE in the UK for those under 55 years old.〔http://www.nice.org.uk/nicemedia/pdf/CG034NICEguideline.pdf, p19〕 ==Diuretics== Diuretics help the kidneys eliminate excess salt and water from the body's tissues and blood. * Loop diuretics: * * bumetanide * * ethacrynic acid * * furosemide * * torsemide * Thiazide diuretics: * * epitizide * * hydrochlorothiazide and chlorothiazide * * bendroflumethiazide * Thiazide-like diuretics: * * indapamide * * chlorthalidone * * metolazone * Potassium-sparing diuretics: * * amiloride * * triamterene * * spironolactone Only the thiazide and thiazide-like diuretics have good evidence of beneficial effects on important endpoints of hypertension, and hence, should usually be the first choice when selecting a diuretic to treat hypertension. The reason why thiazide-type diuretics are better than the others is (at least in part) thought to be because of their vasodilating properties. 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 JNC8 (Eighth Joint National Committee on the Prevention, Detection, Evaluation, and Treatment of High Blood Pressure) recommends thiazide-type diuretics to be one of the first-line drug treatments for hypertension, either as monotherapy or in combination with calcium channel blockers, ACE inhibitors, or angiotensin II receptor antagonists.〔 Despite thiazides being cheap and effective, they are not prescribed as often as some newer drugs. This is because they have been associated with increased risk of new-onset diabetes and as such are recommended for use in patients over 65 where the risk of new-onset diabetes is outweighed by the benefits of controlling systolic blood pressure. Another theory is that they are off-patent and thus rarely promoted by the drug industry. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Antihypertensive drug」の詳細全文を読む スポンサード リンク
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