A pocket calculator program for prediction of warfarin maintenance dose

Area of Science:

• Pharmacology
• Medical Informatics

Background:

• Warfarin dosing requires careful titration to achieve therapeutic anticoagulation while minimizing bleeding risk.
• Estimating initial maintenance doses can be challenging, often relying on empirical methods or nomograms.

Purpose of the Study:

• To present a programmable calculator program for estimating warfarin maintenance dose requirements.
• To provide a method for dose estimation after initial warfarin administration based on prothrombin time (PT) values.

Main Methods:

• Development of a 398-step program for the TI59 programmable calculator.
• The program utilizes patient data, including PT values (≥20), to calculate estimated maintenance warfarin doses.
• The calculation is based on equations derived from published literature.

Main Results:

• The program provides an estimated maintenance warfarin dose after specific initial dosing regimens.
• It can be used after three 10 mg doses or any dose series resulting in a PT ≥ 20.
• The calculated doses serve as a potential starting point for ongoing warfarin therapy.

Conclusions:

• The presented TI59 program offers a tool for estimating warfarin maintenance doses.
• Further clinical evaluation is necessary to confirm the accuracy and reliability of the incorporated equations.
• The program may assist clinicians in initiating maintenance warfarin therapy more efficiently.