[New anticoagulants]

A large number of newly developed platelet aggregation inhibitors and anticoagulants are currently being investigated in clinical studies. Most of these new agents are targeted to haemostatic pathways that have recently been shown to be of importance in vivo and usually have a higher efficacy than the currently available anticoagulants. The new platelet aggregation inhibitors can be divided into thienopyridine derivatives (ticlopidine, clopidogrel) and glycoprotein IIb/IIIa receptor antagonists (abciximab, eptifibatide, tirofiban). The new inhibitors of fibrin synthesis can be divided into direct thrombin inhibitors (hirudine, melagatran, ximelagatran), specific factor Xa inhibitors (pentasaccharides: fondaparinux, idraparinux) and inhibitors of the tissue thromboplastin factor VIIa complex (recombinant nematode anticoagulant protein c2, inactivated factor VIIa, recombinant tissue factor pathway inhibitor). In some cases this also results in a (relatively modest) increase in the risk of bleeding. The clinical use of the new compounds is often much more convenient than that of the presently available anticoagulants.