CGS 15435 has a long duration of action, since the increases in the plasma levels of TxB₂ are prevented even at 24 h after CGS 15435 administration. CGS 15435 significantly inhibits TxB₂ formation 4, 6, 12 and 24 h after dosing. Administration of CGS 15435 0.25 or 24 h prior to Arachidonic acid (AA) produced no increase in TxB₂ in the surviving animals (4/4 and 5/6, respectively). The final TxB₂ levels in the CGS15435A (0.25 and 24 h pretreatment) groups are significantly lower (P<0.05) than those seen in the AA or the Dazoxiben (2 h pretreatment) groups^[1].