Antihypertensive Agents: Understanding Hypertension

Definition and Classification of Hypertension

• Hypertension is defined as systolic BP above 140 mm Hg or diastolic BP above 90 mm Hg
• Classification of hypertension:
  • Normal: systolic BP ≤ 100 mm Hg and diastolic BP ≤ 90 mm Hg
• There are two types of hypertension: essential and secondary hypertension

Essential Hypertension

• Accounts for ~95% of all cases of hypertension
• Also referred to as primary or idiopathic hypertension
• Characterized by an absence of identifiable secondary cause
• Risk factors include:
  • Sedentary lifestyle
  • Obesity
  • Insulin resistance (metabolic syndrome)
  • Salt/sodium sensitivity
  • Alcohol intake
  • Age
  • Family history

Secondary Hypertension

• Attributed to an identifiable cause
• Examples of causes:
  • Aldosteronism
  • Hyperthyroidism
  • Glucocorticoid excess
  • Renovascular disease
  • Renal failure
  • Pheochromocytoma
• Treatment targets the underlying cause

Importance of Treating Hypertension

• Sustained arterial hypertension damages blood vessels in the kidney, heart, and brain
• Leads to increased incidence of renal failure, cardiac failure, and stroke
• Effective pharmacologic lowering of blood pressure prevents damage to blood vessels and reduces morbidity and mortality rate

Treatment of Hypertension

• Two therapeutic interventions: non-pharmacologic and pharmacological

Non-Pharmacologic Therapy

• Low sodium chloride diet
• Weight reduction
• Exercise
• Cessation of smoking
• Decrease in excessive consumption of alcohol
• Avoid stress

Pharmacological Therapy

• Anti-hypertensive drugs lower blood pressure by decreasing cardiac output or total peripheral vascular resistance or both
• Classified according to principal regulatory site or mechanism of action:
  • Beta adrenergic blockers (e.g. Atenolol, Propranolol, Metoprolol, Labetalol)
  • Alpha blockers (e.g. Prazosin)
  • Centrally acting anti-hypertensive (e.g. Methyldopa)
  • Diuretics
  • Direct vasodilators
  • Angiotensin converting enzyme inhibitors
  • Angiotensin II receptor blockers
  • Calcium channel blockers

Learn about hypertension, its classification, and the two general types of hypertension. This quiz covers the definition of hypertension, blood pressure levels, and essential hypertension.