Chapter 22: Antihypertensive Drugs

The content reviews autonomic nervous system mechanisms regulating blood pressure and integrates the JNC 8 diagnostic and treatment framework. Seven major drug classes are systematically analyzed: adrenergic agents including central alpha2 agonists, peripheral alpha1 antagonists, beta adrenergic blockers, and combined alpha-beta blocking agents; angiotensin-converting enzyme inhibitors that interrupt the renin-angiotensin-aldosterone system; angiotensin II receptor antagonists providing selective blockade at the AT1 receptor; calcium channel blocking agents that promote vascular smooth muscle relaxation; diuretic preparations across loop, thiazide, and potassium-sparing categories; direct vasodilators acting on vascular tissue; and direct renin inhibitors. Therapeutic mechanisms encompass reduction of systemic vascular resistance, suppression of cardiac output, modulation of the renin-angiotensin-aldosterone pathway, and vascular smooth muscle relaxation. Beyond hypertension management, these agents address heart failure pathophysiology, post-infarction ventricular remodeling, progressive chronic kidney disease, diabetic nephropathy complications, and hypertensive emergencies. The chapter identifies significant adverse reactions including initial dose syncope, postural blood pressure changes, compensatory tachycardia, erectile dysfunction, immunologic angioedema, metabolic complications such as hyperkalemia, and pregnancy-related teratogenicity warranting black box warnings. Comprehensive nursing assessment encompasses hemodynamic monitoring, laboratory evaluation including renal and hepatic function, electrocardiographic examination, and ophthalmologic screening for end-organ damage. Patient education addresses medication adherence, titration protocols, orthostatic safety measures, and recognition of abrupt withdrawal rebound phenomena. Integration of nonpharmacologic approaches including dietary sodium restriction, weight management, physical conditioning, and stress reduction techniques forms the foundation for sustained hypertension control and prevention of target organ dysfunction.