Pharmacy-managed protocol for warfarin use in orthopedic surgery patients

Area of Science:

• Pharmacology
• Clinical Pharmacy
• Thrombosis Management

Background:

• Warfarin is crucial for antithrombotic prophylaxis in orthopedic surgery.
• Optimizing warfarin dosing is essential to balance efficacy and safety.
• Existing physician-determined dosing may not consistently achieve therapeutic goals.

Purpose of the Study:

• To evaluate a pharmacy-managed warfarin dosing protocol for orthopedic surgery patients.
• To compare the protocol's effectiveness against physician-determined dosing for orthopedic antithrombotic prophylaxis (OAP).
• To assess the protocol's ability to achieve laboratory and clinical goals.

Main Methods:

• A prospective study comparing a "protocol" group with protocol-determined warfarin dosing to a "physician" group with physician-determined dosing.
• Data collected on OAP use, prothrombin times (PTs), International Normalized Ratio (INR), thrombotic events, and bleeding episodes.
• Analysis of factors associated with elevated PTs in the protocol group.

Main Results:

• OAP use increased from 89% (physician group) to 98% (protocol group).
• 66% of PTs in the protocol group were within the target INR range (1.6-3.2) post-operative day 1.
• Clinically apparent thrombotic events and bleeding were infrequent and comparable between groups.

Conclusions:

• A pharmacy-managed warfarin dosing protocol successfully achieved therapeutic goals for OAP.
• The protocol facilitated nearly universal OAP use in high-risk orthopedic surgery patients.
• Protocol adjustments were made for specific patient demographics (e.g., elderly women) based on PT analysis.