Overview of Anti-Hypertensive Medications

Introduction

• Antihypertensive medications treat high blood pressure (hypertension).
• Easy way to remember main classes: ABCD
  • A: ACE inhibitors, ARBs, Alpha blockers
  • B: Beta blockers
  • C: Calcium channel blockers
  • D: Diuretics
• Other medications: Central agonists, Vasodilators

Drug Classes and Suffixes

• ACE inhibitors: End in "pril" (e.g., Lisinopril, Enalapril)
• ARBs: End in "sartan" (e.g., Losartan, Valsartan)
• Alpha blockers: End in "osin" or "zosin" for selective alpha-1 (e.g., Doxazosin, Terazosin)
• Beta blockers: End in "lol" (e.g., Metoprolol, Labetalol)
• Calcium channel blockers: Dihydropyridines end in "dipine" (e.g., Amlodipine, Nicardipine)
• Diuretics: Many end in "ide" (e.g., Furosemide, Hydrochlorothiazide)

Mechanism of Action

ACE Inhibitors

• Inhibit angiotensin-converting enzyme (ACE)
• Decrease formation of angiotensin-2, reducing blood pressure by minimizing vasoconstriction and sodium/water reabsorption.

ARBs

• Block angiotensin-2 receptors, preventing angiotensin-2 from raising blood pressure.

Alpha Blockers

• Block alpha-1 receptors, reducing vasoconstriction and blood pressure.
• Sympathetic catecholamines like norepinephrine and epinephrine normally bind to these receptors.

Beta Blockers

• Block beta-1 receptors in the heart, reducing heart rate and stroke volume, leading to decreased blood pressure.

Calcium Channel Blockers

• Dihydropyridines: Block calcium channels on blood vessels, causing vasodilation, reducing blood pressure.
• Non-dihydropyridines: Block calcium channels on cardiac cells, decreasing heart rate and contraction.

Diuretics

• Facilitate diuresis by inhibiting sodium and water reabsorption in kidneys, decreasing plasma volume and blood pressure.

Blood Pressure Equation

• Blood Pressure = Cardiac Output x Systemic Vascular Resistance (SVR)
• Cardiac Output = Heart Rate x Stroke Volume

Effects on Blood Pressure

• ACE Inhibitors/ARBs: Decrease SVR and stroke volume
• Alpha Blockers: Decrease SVR
• Beta Blockers: Decrease heart rate and stroke volume
• Calcium Channel Blockers: Decrease SVR (dihydropyridines) and heart rate/stroke volume (non-dihydropyridines)
• Diuretics: Decrease stroke volume

Conclusion

• This overview helps in understanding the main antihypertensive classes and their mechanisms.
• Further details can be found on the EasyMed website and linked resources.