Platelet glycoprotein IIb/IIIa inhibitors (abciximab, eptifibatide, tirofiban) bind to the glycoprotein IIb/IIIa receptor on the surface of platelets and prevent binding of fibrinogen, von Willebrand factor, and other adhesive molecules to the receptor sites, thereby blocking platelet aggregation. They are used as an adjunct to heparin and aspirin therapy in patients undergoing percutaneous transluminal coronary procedures, including angioplasty and stenting (abciximab and eptifibatide). Eptifibatide and tirofiban are used in unstable angina and non–Q wave myocardial infarction in high-risk patients. Abciximab is used in unstable angina where percutaneous coronary intervention is planned.