Tirofiban (MK-383, Aggrastat) is a nonpeptide derivative of tyrosine that selectively inhibits the GP-IIb/IIIa receptor, with minimal effects on the ɑvβ3 vitronectin receptor. [1][2] It inhibits platelet aggregation of gel-filtered platelets induced by 10 μM ADP with IC50 of 9 nM, but the IC50 for inhibition of human umbilical vein adhesion to vitronectin, which depends on ɑvβ3 vitronectin receptors, is 62 μMol/L. [3]

Tirofiban (10 to 500 mg/kg or 360-min continuous i.v. infusions of 1 to 10 micrograms/kg/min) inhibits platelet aggregation responses to ADP and collagen in canine models. [4] When administered to humans at 0.15μg/kg/min for 4 h, Tirofiban produced a 2.5-fold increase in bleeding time and 97% inhibition of ADP-induced platelet aggregation. [5][6]