How to monitor the dosage of warfarin

To use and monitor warfarin therapy appropriately, the clinician must understand the pharmacodynamics and time profile of this agent and how the clotting cascade and coagulation inhibitor system are affected early in therapy. The redefined guidelines for PT monitoring require that the INR be used to monitor all patients receiving warfarin. Safety also requires that patients be monitored closely and that both the clinician and the patient be alert to potentially interacting variables. With long-term therapy, one must continually reassess the risk-to-benefit ratio of continuing therapy, changing the level of anticoagulation intensity, or discontinuing therapy. Finally, it is particularly important that patients understand the potential risks and benefits of anticoagulation therapy and how to monitor themselves. Patients should be encouraged to contact the appropriate clinician immediately with any questions that may influence the continued safe and effective use of warfarin.