Cardiovascular System Drugs Notes

Antihypertensive Drugs

  • Hypertension management often involves multiple drug classes.
  • Some antihypertensive drugs also help lower lipids, reducing cardiovascular risk.

ACE Inhibitors

  • Suffix: "-pril"
  • Mechanism: Block the enzyme that creates Angiotensin II (AT2).
  • AT2 constricts blood vessels, so blocking its formation leads to:
    • Relaxation of blood vessels.
    • Lowered blood pressure (BP).
    • Reduced cardiac workload.

ARBs (Angiotensin II Receptor Blockers)

  • Suffix: "-tan"
  • Mechanism: Block AT2 receptors.
  • By blocking AT2 receptors, they prevent AT2 from constricting blood vessels, leading to:
    • Relaxation of blood vessels.
    • Lowered blood pressure.

Beta-Blockers

  • Suffix: "-lol"
  • Mechanism: Lower heart rate and reduce the heart's demand for oxygen.
    • Decreased heart rate.
    • Decreased blood pressure.

Calcium Channel Blockers

  • Suffix: "-pine"
  • Mechanism: Prevent calcium entry into heart and vessel walls.
    • Relaxation of blood vessels.
    • Decreased blood pressure.

Diuretics

  • Function: Remove excess salt and water from the body.
    • Decreased blood pressure.

Diuretic Drugs

  • Reduce excess fluid and heart strain.
  • Act on the nephrons in the kidneys.
  • Different types act on different parts of the nephron.
  • Mechanism: Block salt Na^+ reabsorption, forcing it to stay in the urine.
  • Water follows sodium, leading to increased urine production.
  • Less fluid in blood vessels results in:
    • Lower blood pressure.
    • Decreased swelling (edema).
  • Less blood volume equals less pressure on the heart and arteries.

Antilipemic Drugs

  • Lipid-lowering agents reduce high cholesterol and triglycerides in the blood.

HMG-CoA Reductase Inhibitors (Statins)

  • Suffix: "-statins"
  • Mechanism: Block an enzyme in the liver that produces cholesterol (LDL).

Fibrates (Fibric Acid Derivatives)

  • Function: Lower triglyceride levels.
  • Triglycerides are excess calories from sugars, fats, and alcohol stored in fat cells.

Bile Acid Sequestrants

  • Mechanism: Bind to bile acids in the GI tract, forming an insoluble complex.
  • The liver then uses cholesterol to make more bile acids, lowering cholesterol levels.

Antiarrhythmia Drugs

Scenarios

  • Atrial Fibrillation: Irregular heartbeat (arrhythmia) where the atria quiver or fibrillate.

Treatment Goal

  • Slow down the heart rate.
  • Help the heart to beat stronger and more regularly.

Drug Classes

  • Beta Blockers:
    • Mechanism: Block adrenaline effects, slowing heart rate.
  • Calcium Channel Blockers:
    • Mechanism: Block calcium channels, slowing heart rate.
  • Potassium Channel Blockers:
    • Mechanism: Block potassium channels, prolonging the time during which the heart cannot be stimulated.
  • Digitalis:
    • Mechanism: Increases the force of the heart’s contractions, slows the heart rate, and slows down the electrical conduction in the AV node.