The only iso-form of cyclooxygenase expressed in thrombocytes is cyclooxygenase-1. In endothelial cells and in smooth muscle cells of the vascular wall both iso-forms are expressed. Selective inhibition of cyclooxygenase-2 by coxibs in the vascular system deprives this class of non-steroid antirheumatics of their anti-aggregation effect. At present a discussion is under way on the „prothrombogenic potential“ of coxibs, which however so far was not unequivocally proved.On the other hand the antiphlogistic effect of coxibs could have a favourable impact on the „inflammatory component“ in the genesis of atherosclerosis. Further investigations are needed for evaluation of these problems.

        Key words: cyclooxygenase-1, cyclooxygenase-2, prothrombogenic potential, cardiovascular risk, cardiovascular safety