Belong to class of antithrombotic agents.
Focus on preventing arterial rather than venous thrombogenesis, but are useful in certain types of venous thrombotic disease.
Useful in acute and chronic clinical processes.
Function to counteract platelet aggregation at sites of arterial endothelial injury or unstable atherosclerotic plaques.
Purpose is to prevent arterial obstruction or occlusion and downstream micro embolism into the systemic circulation.
Platelet function inhibition has an important process and life-threatening condition such as strokes, peripheral arterial disease, acute coronary syndromes and acute myocardial infarction.
Antiplatelet agents are medications that inhibit platelet aggregation and are primarily used to prevent arterial thrombosis.
Antiplatelet agents play a role in the management of cardiovascular diseases, particularly in the prevention of myocardial infarction (MI) and stroke.
The most commonly used antiplatelet agents include:
1. Aspirin (ASA): It irreversibly inhibits cyclooxygenase-1 (COX-1), reducing thromboxane A2 production, which is essential for platelet aggregation.
Common uses: Primary and secondary prevention of cardiovascular events
2. Thienopyridines: This class includes clopidogrel, prasugrel, and ticlopidine.
P2Y12 inhibitors block ADP (Adenosine diphosphate) receptor on platelets Clopidogrel (Plavix) Prasugrel (Effient) Ticagrelor (Brilinta)
Block ADP receptor on platelets Often used in combination with aspirin (dual antiplatelet therapy) after stents or acute coronary syndromes
These agents irreversibly block the P2Y12 component of ADP receptors on the platelet surface, preventing activation of the GPIIb/IIIa receptor complex and subsequent platelet aggregation.
3. Non-thienopyridine P2Y12 inhibitors: Ticagrelor is a reversible P2Y12 inhibitor that does not require metabolic activation, providing a consistent antiplatelet effect.
4. Glycoprotein IIb/IIIa inhibitors: These include abciximab, eptifibatide, and tirofiban, which inhibit the final common pathway of platelet aggregation by blocking the GPIIb/IIIa receptor.
Mechanism: Block the final common pathway of platelet aggregation Primarily used in acute settings like heart attacks or during procedures
5. Dipyridamole: Often used in combination with aspirin, it inhibits platelet aggregation through multiple mechanisms, including inhibition of cyclic nucleotide phosphodiesterase and blockade of adenosine uptake.
6. Protease-activated receptor-1 (PAR-1) inhibitors: Vorapaxar is an example that inhibits thrombin-induced platelet aggregation.
7. Phosphodiesterase inhibitors Cilostazol (Pletal) Dipyridamole (Persantine) Mechanism: Increase cAMP levels in platelets, inhibiting aggregation
Common clinical applications include prevention of stroke, treatment after heart attacks, management after stent placement, and prevention of clots in people with risk factors for cardiovascular disease.
Women treated with antiplatelet drugs experience more bleeding complications than men, probably because they are generally older, have worse renal function, and more comorbidities.
Antiplatelet drugs ticagrelor and prasurgrel act more quickly in patients than clopidogrel and is recommended may be used over clopidogrel after PCI.