What is the mechanism of action of Eptifibatide?

Eptifibatide functions as a specific inhibitor of the glycoprotein IIb/IIIa receptor on platelets. By reversibly binding to this receptor, Eptifibatide prevents the binding of fibrinogen, which is essential for platelet aggregation. This action is crucial because the GP IIb/IIIa receptor is a final common pathway for platelet activation, where fibrinogen serves as a bridge between platelets, facilitating their clumping together. By blocking this binding site, Eptifibatide effectively reduces thrombus formation and is particularly useful in acute coronary syndromes and during percutaneous coronary interventions.

The other actions listed do not accurately describe the mechanism of Eptifibatide. It does not inhibit thrombin, nor does it interfere with P2Y12 receptors, which are linked to ADP signaling in platelet activation. Promoting platelet aggregation is opposite to what Eptifibatide achieves; instead, it acts to inhibit this process. Thus, the correct answer highlights the drug's role in preventing fibrinogen from enabling platelet aggregation through its effect on the GP IIb/IIIa receptor.