SIGNIFICANT inhibition of Xa & IIa • • • MINOR inhibition of VIIa, IXa, & XIIa • • • Active clotting factors INACTIVATED • • • INDIRECT thrombin inhibitor • • • enhances effects of antithrombin III
HEPARIN
LOW MOLECULAR WEIGHT HEPARINS
ENHANCES the effects of antithrombin III • • • SIGNIFICANT inhibition of Xa • • • Some inhibition of IIa • • • Active clotting factors INACTIVATED
ENOXAPARIN • • Lovenox
DALTEPARIN • • Fragmin
VITAMIN K ANTAGONIST
Interacts with Vit K cycle • • • Factor II, VII, IX, & X • • • INHIBITS Vit K epoxide reductase ( VKORC1 ) which converts Vit K to its activa form ( KH2 ) →
→ No longer a cofactor of carboxylase → → less K → Less K dependent clotting factors produced → ALSO inhibits protein C and S
WARFARIN • • Coumadin
FACTOR Xa INHIBITORS
ACUTE
FONDAPARINUX • • Atrixa
Augments function of ATII • • Significant inhibition of Xa only • • Active clotting factors inactivated (Only Xa)
CHRONIC
DOES NOT AFFECT ANTITHROMBIN • • • Directly inhibits Factor Xa by BLOCKING the active site