Knowing your anti-coagulants and anti-platelets

I’ve noticed as a student that lots of people get them confused. It’s simple because they both thin the blood right?

Unfortunately, it’s not appropriate to mix up the two terms. Precision is key guys!

Want a quick two min crash course? Read on!


Affect primary hemostasis as they target platelet aggregation. Platelet aggregation involves linking to other platelets through fibrinogen through receptors called glycoprotein 2b3a (GP2b3a). This linking forms a platelet plug.


Aspirin – inactivates cyclo-oxygenase 1 (COX-1) there by reducing Thromboxane A2 (TXA2) which promotes aggregation. Clopidogrel – inhibit ADP dependent aggregation. This reduces the ability for the GP2b3a receptor to be expressed. GP2b3a antagonists (Abciximab) – prevents fibrinogen to bind to the receptor.


Act on the coagulation cascade. The coagulation cascade occurs in secondary hemostasis with the primary goal to convert fibrinogen into fibrin. This would stabilize the platelet plug as fibrin a lot more stable than fibrinogen.


Warfarin – prevents the synthesis of Vit K dependent coag factors (2,7,9,10, C and S). Heparin – activates anti-thrombin 3 (AT3) and has an effect on thrombin and Xa. Low Molecular Weight Heparin – activate AT3 but only has an effect on Xa. Xa inhibitors – inhibit Xa. Direct thrombin inhibitors inhibits thrombin.

From this, I hope you can see why it’s very wrong to call warfarin an anti-platelet. Similarly, aspirin is not an anti-coagulant.

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