Introduction
Illustrated mechanism of action
Examples of Medication Brand Names (with Images)
Indication
Side Effects
Precautions & Contraindications
Monographs
Reference
Antiplatelet medications are primarily used for the management and prevention of cardiovascular disease (CVD) related events .
-When the body senses injury, it rushes to heal—and one of the first responders in this process is a group of tiny blood cells called platelets. They stick together at the site of damage, forming clots to stop bleeding. But what happens when this clotting system becomes too eager, forming clots inside blood vessels without any injury? That’s where antiplatelet drugs step in. Acting like a brake system for platelets, these medications help prevent dangerous clots that can lead to heart attacks, strokes, or other vascular problems. Whether it’s after a stent placement or in patients with atherosclerosis, antiplatelets are essential players in modern cardiovascular medicine—subtly saving lives, one platelet at a time.
Mechanism of action
1. Aspirin (Cyclooxygenase Inhibitor)
Mechanism: Irreversibly acetylates COX-1 at Ser-529, blocking arachidonic acid metabolism → inhibits thromboxane A₂ (TXA₂) synthesis.
Effect: Lifelong platelet inhibition (8-10 days) since platelets lack nuclei to regenerate COX-1.
2. Clopidogrel/Prasugrel (P2Y₁₂ Inhibitors)
Mechanism:
• Prodrugs metabolized to active compounds that irreversibly bind ADP receptors (P2Y₁₂).
• Block ADP-mediated platelet activation pathways.
3. Ticagrelor
Mechanism: Reversibly binds P2Y₁₂ as a noncompetitive antagonist, preventing ADP signaling.
4. Glycoprotein IIb/IIIa Inhibitors
Mechanism:
• Abciximab/Tirofiban block fibrinogen binding to GP IIb/IIIa receptors.
• Prevent final common pathway of platelet aggregation.
5. Dipyridamole
Mechanism:
• Phosphodiesterase inhibition → ↑cAMP levels → reduced calcium mobilization.
• Stimulates prostacyclin release and inhibits TXA₂.
6. Vorapaxar (PAR-1 Inhibitor)
Mechanism: Blocks thrombin-activated PAR-1 receptors, disrupting thrombin signaling.
Examples of medications
Cilostazol Tablets
Clopidogrel Tablets
plavix Tablet
Aspirin Tablets
Dipyridamole Injection
Eptifibatide Injection
Integrilin Injection
Ticagrelor Tablets
Indications
Antiplatelet medications are divided into oral and parenteral agents. Oral agents subdivide further based on the mechanism of action. Aspirin was the first antiplatelet medication and is a cyclooxygenase inhibitor. Other oral antiplatelet agents include clopidogrel, ticagrelor, prasugrel, pentoxifylline, cilostazol, and dipyridamole. Glycoprotein IIb/IIIa inhibitors such as tirofiban and eptifibatide are only available as parenteral agents and are used in acute coronary syndrome (ACS).[1]
The following is a list of indications of antiplatelet medications:
Acute coronary syndrome
Post-percutaneous coronary intervention (PCI) with stenting
Mechanical heart valves in combination with warfarin
Acute ischemic stroke
Post-percutaneous intervention of peripheral arterial disease
Device closure of an atrial septal defect (ASD) for at least 6 months
Stable angina
Post-coronary artery bypass grafting surgery
Essential thrombocytosis
Primary prevention of coronary artery disease
Prevention of colon cancer
Kawasaki disease
Acute rheumatic disease
Post patent ductus arteriosus (PDA) device closure for the first 6 months
Acute pericarditis
Atrial fibrillation with a high risk of stroke
Primary prevention of venous thromboembolism
.Common side effects
.Gastrointestinal issues: Indigestion, stomach pain, nausea, diarrhea, and heartburn due to stomach lining irritation.
.Bleeding tendencies: Increased nosebleeds, easy bruising, and prolonged bleeding from minor cuts.
.Headaches: Frequently reported with medications like cilostazol
Fatigue.
Serious side effects
.Jaundice
.Neurological symptoms: Slurred speech, weakness/numbness in limbs.
.Allergic reactions: Swelling (face, throat), rash, itching, or difficulty breathing.
.Severe bleeding: Blood in vomit (resembling coffee grounds), black/tarry stools, blood in urine, or uncontrolled bleeding.
Precautions & Contraindications
.All antiplatelet drugs can cause bleeding. Avoid in patients who are at a high risk of bleeding or where the consequences of bleeding would be severe - for example, active peptic ulcer disease, uncontrolled hypertension.
.Hypersensitivity and allergy. NICE guidance suggests that true hypersensitivity to aspirin (characterised by rash, urticaria and angio-oedema) is rare.
.Aspirin can cause bronchospasm and worsen pre-existing asthma. A systematic review estimated the prevalence of aspirin-exacerbated asthma in adults with pre-existing asthma as 21% (from oral provocation testing). From this, it suggests that approximately 80% of asthmatics can take aspirin safely but caution should be exercised. Always check about previous experiences with aspirin and other NSAIDs and warn to stop aspirin if their asthma deteriorates. High-risk features for developing aspirin-induced asthma include severe asthma, nasal polyps, urticaria and rhinitis.
.Hypertension should be controlled (blood pressure <150/90 mm Hg) before commencing treatment.
Monographs