<P> 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 . </P> <P> 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 . </P>

Class of drugs administered to lower high blood pressure