New trends in thromboxane and prostacyclin modulators

Thromboxane A(2) (TXA(2)) and prostacyclin (PGI(2)) are two labile products formed from arachidonic acid by the way of cyclooxygenase. An overproduction of thromboxane A(2) has been detected in a series of diseases whereby this prostanoid is assumed to contribute to the underlying pathomechanisms by its potent stimulation of platelet aggregation and smooth muscle contraction. This increased TXA(2) biosynthesis is frequently accompanied by a stimulation of prostacyclin formation which is one of the most potent inhibitors of platelet aggregation and smooth muscle contraction. Therefore, TXA(2)/prostaglandin endoperoxide H-2 receptor antagonists, thromboxane synthase inhibitors and drugs which combine both activities have been developed with the aim to suppress the formation and/or the action of thromboxane A(2) Since prostacyclin has been demonstrated to counterbalance the pathological effects of TXA(2), several PGI(2) agonists have also been developed. This review will highlight the evolution and some of the latest findings in the field of prostacyclin and thromboxane A(2) modulators mainly those which are under clinical evaluation or marketed.