Warfarin therapy: Evolving strategies in anticoagulation

Warfarin is the oral anticoagulant most frequently used to control and prev ent thromboembolic disorders. Prescribing the dose that both avoids hemorrh agic complications and achieves sufficient suppression of thrombosis requir es a thorough understanding of the drug's unique pharmacology. Warfarin has a complex dose-response relationship that makes safe and effective use a c hallenge. For most indications, the dose is adjusted to maintain the patien t's International Normalized Ratio (INR) at 2 to 3. Because of the delay in factor II (prothrombin) suppression, heparin is administered concurrently for four to five days to prevent thrombus propagation. Loading doses of war farin are not warranted and may result in bleeding complications. interacti ons with other drugs must be considered, and therapy in elderly patients re quires careful management Current dosing recommendations are reviewed, and practical guidelines for the optimal use of warfarin are provided.