Cardiovascular and Systemic Drugs: Classes, Uses and Mechanisms

Posted on Mar 2, 2026 in Medicine & Health

Anti-arrhythmic Drugs

Anti-arrhythmic drugs are medications used to treat abnormal heart rhythms (arrhythmias). They work by modifying the electrical activity of the heart.

Classification

  1. Class I: Sodium channel blockers (e.g., Quinidine, Lidocaine)
  2. Class II: Beta blockers (e.g., Propranolol)
  3. Class III: Potassium channel blockers (e.g., Amiodarone)
  4. Class IV: Calcium channel blockers (e.g., Verapamil)

Anticoagulants

Anticoagulants are drugs that prevent blood clotting.

  • Warfarin: Inhibits vitamin K–dependent clotting factors (II, VII, IX, X).
  • Heparin: Enhances antithrombin III, inhibiting thrombin and factor Xa.

Gout

Gout is a condition characterized by sudden, severe joint pain due to uric acid buildup.

Drugs:

  • Allopurinol: Inhibits xanthine oxidase, reducing uric acid production.
  • Colchicine, NSAIDs, Corticosteroids: Used for acute attacks.

Aspirin as Antiplatelet

Aspirin irreversibly inhibits COX-1, reducing thromboxane A2 production and thus inhibiting platelet aggregation.

Anabolic Steroids & Glucocorticoids

  • Anabolic steroids: Synthetic androgens that promote muscle growth.
  • Glucocorticoids: Steroids with anti-inflammatory and immunosuppressive effects.

Plasma Volume Expanders & Substance-P

  • Plasma volume expanders: Solutions (e.g., Dextran, Albumin) that increase blood volume.
  • Substance-P: A neuropeptide involved in pain transmission and inflammation.

Nitroglycerin & Inotropic Agents

  • Nitroglycerin: Releases NO, relaxing vascular smooth muscle and reducing preload.
  • Inotropic agents: Drugs (e.g., Digoxin, Dobutamine) that increase cardiac contractility.

Drugs Acting on the Renin–Angiotensin System

  • ACE inhibitors (e.g., Lisinopril).
  • ARBs (e.g., Losartan).
  • Renin inhibitors (e.g., Aliskiren).
  • Aldosterone antagonists (e.g., Spironolactone).

Tocolytics

Tocolytics are drugs used to suppress preterm labor (e.g., Nifedipine, Salbutamol).

5-HT Antagonists

5-HT antagonists (e.g., Ondansetron) block serotonin receptors and are used for nausea/vomiting, migraine, and other conditions.

Drugs Used in Shock

  • Vasopressors (e.g., Noradrenaline).
  • Inotropes (e.g., Dobutamine).
  • Fluids (e.g., Saline).

Oral Hypoglycemic Agents

1. Oral Hypoglycemic Agents

Classification:

  • Sulfonylureas: e.g., Glibenclamide (increase insulin release).
  • Biguanides: e.g., Metformin (decrease hepatic glucose production).
  • DPP-4 inhibitors: e.g., Sitagliptin (increase incretin levels).
  • SGLT2 inhibitors: e.g., Dapagliflozin (increase glucose excretion).
  • Thiazolidinediones: e.g., Pioglitazone (increase insulin sensitivity).

Autacoids & H1-Receptor Antagonists

  • Autacoids: Locally acting biologically active substances (e.g., histamine, prostaglandins).
  • Classification: Amines (histamine), Peptides (angiotensin), Lipid-derived (prostaglandins).
  • H1-receptor antagonists: e.g., Diphenhydramine (antihistaminic, sedative).

Diuretics

3. Diuretics

Classification:

  • Loop diuretics: e.g., Furosemide (inhibit Na-K-2Cl cotransport).
  • Thiazides: e.g., Hydrochlorothiazide.
  • Potassium-sparing: e.g., Spironolactone.

Arachidonic Acid Pathway & Prostaglandins

4. Arachidonic Acid Pathway & Prostaglandins

Pathway: Arachidonic acid → COX → Prostaglandins, Thromboxanes; LOX → Leukotrienes.

Prostaglandins:

  • Physiological: Protect gastric mucosa, regulate renal blood flow.
  • Pathological: Inflammation, pain, fever.

NSAIDs Classification

  • Non-selective COX inhibitors: e.g., Aspirin.
  • COX-2 selective: e.g., Celecoxib.