Antihypertensives

Introduction & goals

• Hypertension — the commonest cardiovascular disease and the principal cause of stroke; a major risk factor for coronary artery disease, MI, heart failure, chronic kidney disease and aortic dissection. Cardiovascular risk is continuous — doubling for every 20/10 mmHg rise above 115/75 mmHg.
• Goal of therapy — to reduce cardiovascular morbidity and mortality (especially stroke and heart failure), not merely to lower a number — drug choice should rest on outcome evidence. BP-lowering per se is the dominant benefit; class differences are secondary.
• Haemodynamic basis — BP = cardiac output × peripheral vascular resistance. Every antihypertensive acts on CO, PVR or blood volume, at four control sites — arterioles, capacitance venules, heart and kidney — modulated by the baroreflex and the renin–angiotensin–aldosterone system (RAAS).
• Practical frame — four first-line classes (ACE-I, ARB, CCB, thiazide/thiazide-like diuretic); β-blockers are reserved for compelling indications. About two-thirds of patients need ≥2 drugs, so guidelines favour early low-dose single-pill combinations.