Antiplatelet Drugs Made Simple: A Quick Overview

Introduction to Antiplatelet Drugs

• Prevent platelet aggregation → inhibit thrombus formation
• Primarily used in arterial thrombosis
• Important in cardiovascular and cerebrovascular disease

List of Common Antiplatelet Agents

      1.Cox Inhibitor E.g. Aspirin

      2. PDE Inhibitor E.g. Dipyridamole

      3. ADP Receptor (P2Y12) Blockers E.g. Ticlopidine, Clopidogrel

      4. GPIIb/IIIa Inhibitors E.g. Abciximab

Aspirin – Mechanism of Action

• Irreversibly inhibits COX-1 enzyme
• ↓ Thromboxane A₂ (TXA₂) → ↓ platelet aggregation
• Effect lasts for lifespan of platelet (7–10 days)

Indications

• Acute coronary syndrome (ACS)
• Secondary prevention of MI and stroke
• Atrial fibrillation (in low-risk patients)
• Post-PCI (Percutaneous Coronary Intervention)

Adverse Effects

• GI irritation, ulcers
• Bleeding
• Tinnitus (high doses)
• Hypersensitivity reactions

Contraindications

• Active GI bleeding or peptic ulcer
• Allergy to NSAIDs
• Children with viral illness (→ Reye's syndrome)
• Severe hepatic or renal impairment

Dipyridamole – Mechanism of Action

• Inhibits phosphodiesterase (PDE) → ↑ cAMP → ↓ platelet aggregation
• Also inhibits adenosine uptake → vasodilation

Indications

• Secondary prevention of ischemic stroke (usually with aspirin)
• Cardiac stress testing (in pharmacologic stress tests)

Adverse Effects

• Headache
• Dizziness
• Hypotension
• GI upset

Ticlopidine – Mechanism of Action

• Irreversibly blocks P2Y12 ADP receptor on platelets → ↓ aggregation

Indications

• Stroke prevention (alternative to aspirin)
• Prevention of stent thrombosis (rare use now)

Adverse Effects

• Neutropenia (requires blood count monitoring)
• Thrombocytopenia
• GI upset
• Rash

Clopidogrel – Mechanism of Action

• Prodrug; irreversibly blocks P2Y12 ADP receptor
• Inhibits platelet aggregation

Indications

• ACS (with or without PCI)
• Stroke prevention
• Peripheral artery disease
• Dual antiplatelet therapy (DAPT with aspirin)

Adverse Effects

• Bleeding
• GI upset
• Rare: Thrombotic thrombocytopenic purpura (TTP)

Abciximab – Mechanism of Action

• Monoclonal antibody against GP IIb/IIIa receptor on platelets
• Prevents fibrinogen binding → blocks platelet aggregation

Indications

• Adjunct in PCI to prevent ischemic complications
• High-risk ACS (short-term use)

Adverse Effects

• Bleeding (especially at vascular access site)
• Thrombocytopenia
• Hypersensitivity (as it's a monoclonal antibody)

Presentation on Understanding Antiplatelet Drugs: Key Facts in Minutes

 

 

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