Structure-function relationships of factor Xa inhibitors: implications for the practicing clinician.

The recent development and approval of novel oral anticoagulants represents a significant success in the intelligent design of target-specific therapeutics. However, while these agents obviate many of the shortcomings of their predecessor (warfarin), they present novel challenges in pharmacologic management as well. Each was designed to have high oral bioavailability and high affinity for its target molecule, conveying significant anticoagulant effects. Yet, such unique drug-ligand binding, coupled with unfamiliar drug interactions and renal-based clearance, represent challenges to clinical management. The current review describes the development and pharmacokinetic properties of these agents, in the context of their clinical utility and pitfalls.