Pretreatment of platelets with terbogrel 1 μM completely inhibits thrombin-induced thromboxane A2 formation (2±1 ng/mL) but does not result in any inhibition of platelet aggregation. Terbogrel (1 μM) completely inhibits U46619-induced thromboxane A2 formation (2±1 ng/mL) but does not result in any inhibition of platelet aggregation. platelet aggregation, and the IC 50 value is 10 nM. Terbogrel inhibits both platelet aggregation and thromboxane A2 formation with an IC 50 of about 10 nM. It inhibits the thromboxane A2 synthase in human gel-filtered platelets with an IC 50 value of 4.0 ± 0.5 nM. Terbogrel blocks the thromboxane A2/endoperoxide receptor on washed human platelets with an IC 50 of 11 ± 6 nM (n = 2) and with an IC 50 of 38 ± 1 nM (n = 15) in platelet-rich plasma. Terbogrel inhibits the collagen-induced platelet aggregation in human platelet-rich plasma and whole blood with an IC 50 of 310 ± 18 nM (n = 8) and 52 ± 20 nM (n = 6), respectively.
