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Chapter 149 Antithrombotic Drugs 2169

Antithrombotic drugs endothelial cells, COX-2 initiates the synthesis of prostacyclin, a
potent vasodilator and inhibitor of platelet aggregation.

Antiplatelet drugs Anticoagulants Fibrinolytic agents Indications
Fig. 149.1 CLASSIFICATION OF ANTITHROMBOTIC DRUGS.
Aspirin is widely used for secondary prevention of cardiovascular
events in patients with coronary artery disease, cerebrovascular
disease, or peripheral vascular disease. Compared with placebo,
aspirin produces about a 25% reduction in the risk of cardiovascular

Fig. 149.2 SITE OF ACTION OF ANTIPLATELET DRUGS. Aspirin inhibits thromboxane A 2 (TXA 2 )
synthesis by irreversibly acetylating cyclooxygenase-1 (COX-1). Reduced TXA 2 release attenuates platelet
activation and recruitment to the site of vascular injury. Clopidogrel, prasugrel, ticagrelor, and cangrelor block
P2Y 12 , a key adenosine diphosphate (ADP) receptor on the platelet surface. Therefore these agents also attenu-
ate platelet recruitment. Vorapaxar inhibits type 1 protease-activated receptor (PAR-1), the major thrombin
receptor on platelets. Abciximab, eptifibatide, and tirofiban inhibit the final common pathway of platelet
aggregation by blocking fibrinogen binding to activated glycoprotein (GP) IIb/IIIa. vWF, von Willebrand
factor.