Key result
Warfarin dose correlates with plasma levels but neither correlates with prothrombin ratio in anticoagulated patients.
Why the study?
Does the measurement of plasma levels of warfarin and warfarin-alcohol correlate with prothrombin ratio in anticoagulated patients?
Observational (n=43)
Does the measurement of plasma levels of warfarin and warfarin-alcohol correlate with prothrombin ratio in anticoagulated patients?
Measurement of plasma levels of warfarin and warfarin-alcohol is likely to be of little clinical help other than to detect failure of compliance or malabsorption.
Plasma warfarin levels may not guide anticoagulation intensity; leaves open the need for better pharmacodynamic markers in prospective studies.
The relationship between dosage, prothrombin ratio, and steady-state plasma concentrations of warfarin and warfarin-alcohol, were determined in 43 patients regularly attending an anticoagulant clinic. The warfarin and warfarin-alcohol concentrations were determined by a gas chromatographic mass spectroscopic (GC/MS) method. A significant correlation was found between the dose and the plasma level of warfarin. There was no significant correlation between the prothrombin ratio and the dose of warfarin, the steady-state plasma levels of warfarin or warfarin-alcohol, or the sum of their plasma concentrations. Measurement of the plasma levels of warfarin and warfarin-alcohol is likely to be of little help clinically other than to detect failure of compliance or malabsorption.
No takes yet. Share an insight, caveat, or question.
Duffield et al. (1979) conducted an observational in Anticoagulated patients (n=43). Warfarin dosage and plasma levels was evaluated on Relationship between dosage, prothrombin ratio, and steady-state plasma concentrations of warfarin and warfarin-alcohol. Warfarin dose significantly correlated with plasma warfarin levels, but neither dose nor plasma levels correlated with the prothrombin ratio in anticoagulated patients.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: