Antihypertensives are drugs used to lower BP in hypertension. Hypertension is a very common disorder, particularly past middle age and hence antihypertensives are very commonly employed drugs in medical practice.. It is not a disease in itself, but is an important risk factor for cardiovascular mortality and morbidity. The cut off manometric reading between normotensives and hypertensives is arbitrary. For practical purposes ‘hypertension’ could be that level of HP at or above which long-term antihypertensive treatment will reduce cardiovascular mortality. The INC 7* (2003) and WHO-ISH© guidelines (2003) have defined it to be 140 mm Hg systolic and 90 mm Hg diastolic, though risk appears to increase even above 120/80 mm Hg. Epidemiological studies have confirmed that higher the pressure (systolic or diastolic or both) greater is the risk of cardiovascular disease.
Majority of cases are of essential (primary) hypertension, i.e. the cause is not known. Sympathetic and renin-angiotensin systems may or may not be overactive, but they do contribute to the tone of blood vessels and cardiac output in hypertensives, as they do in normotensives. Many Antihypertensives interfere with these regulatory systems at one level or the other. Antihypertensives , by chronically lowering BP, may reset the barostat to function at a lower level of BP.