title: Comparison of two methods in the estimation of the pharmacokinetic parameters of phenytoin.
abstract: This report compares two different methods of estimating the pharmaco-kinetic parameters of phenytoin (PHT) from steady-state serum concentration data obtained in clinical practice: the standard two-stage method (STS) and the extended least squares method (ELS). The study was carried out with the data from 27 compliant adult epileptic patients treated with PHT on a monotherapy regimen. Application of Akaike information criterion (AIC) points to a better estimation with the STS method (AIC = 268.05 for ELS; AIC = 114.13 for STS). This was confirmed by calculating the mean prediction error (mpe) and the standard deviation of EMP, which were 0.59 +/- 6.11 mg/l and -0.12 +/- 2.93 mg/l for ELS, and STS methods, respectively. Despite the well-known limitations of the STS method, a simulation study revealed that it can be successfully used when the patients to be included are selected with great care and when reliable serum concentration data are available.
authors.affiliation: Department of Pharmacy, School of Pharmacy, University of Salamanca, Spain.
authors.forename: D
authors.initials: D
authors.lastname: Santos Buelga
authors.forename: A
authors.initials: A
authors.lastname: Vazquez
authors.forename: A C
authors.initials: AC
authors.lastname: Alonso
authors.forename: M J
authors.initials: MJ
authors.lastname: Garcia
authors.forename: A
authors.initials: A
authors.lastname: Dominguez-Gil
mesh_terms: D000328:Adult; D006801:Humans; D008875:Middle Aged; D008954:Models, Biological; D010672:Phenytoin / Q000097:blood / Q000493:pharmacokinetics*; D013223:Statistics as Topic / Q000379:methods
chemical_list: D010672:Phenytoin