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COMPARISON OF METHODS FOR THE PREDICTION OF PHENYTOIN CONCENTRATIONS
Author(s) -
Rodríguez A. Vázquez,
Buelga D. Santos,
González A. C. Alonso,
Sánchez M. J. García,
Hurlé A. DomínguezGil
Publication year - 1991
Publication title -
journal of clinical pharmacy and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.622
H-Index - 73
eISSN - 1365-2710
pISSN - 0269-4727
DOI - 10.1111/j.1365-2710.1991.tb00284.x
Subject(s) - phenytoin , mean squared error , liter , mathematics , statistics , mean absolute error , population , mean squared prediction error , steady state (chemistry) , chemistry , thermodynamics , medicine , epilepsy , physics , environmental health , psychiatry
Summary A comparison was made of different methods for the prediction of the serum concentrations of phenytoin (PHT) at steady‐state with a view to determining which of them had the best predictive performance. The methods employed calculated the predicted concentrations based on a dose steady‐state concentration pair. Two of the methods used involved solving the Michaelis‐Menten equation, determination of a single parameter in each individual and maintaining the K m (Method A) or V max (Method B) values at a constant. Methods C and D were Bayesian techniques that used population parameters determined in a population studied by us (Method C) and parameters drawn from the literature (Method D). Calculation of bias and precision suggests that Method C is the most suitable of those studied, with a mean prediction error (ME) of 0·56 ± 2·16 mg/litre, a mean absolute error (MAE) of 1·76 ± 1·31 mg/litre and a root mean squared prediction error (RMSE) of 2·17 mg/litre. Method C was also the method that showed the lowest percentage of underestimation (5·26%) and overestimation (10·53%).