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.