Application of two-point assay of digoxin serum concentration in studying population pharmacokinetics in Egyptian pediatric patients with heart failure: does it make sense?
Am J Ther
; 12(4): 320-7, 2005.
Article
em En
| MEDLINE
| ID: mdl-16041195
ABSTRACT
Digoxin pharmacokinetics (PK) was studied among a selected group of Egyptian pediatric patients (n = 40) with an age range of 0.33 to 15 years. All the patients had heart failure and were maintained on i.v. digoxin (10 microg/kg/d in 2 equal doses). For population PK analysis, 2 serum samples of digoxin were taken per patient. From 30 patients' trough (before the next dose) and 4 hours postdose samples were obtained, while in the other 10 patients, 0.5- and 6-hour postdose samples were taken. Serum concentrations were measured by fluorescence polarization immunoassay. PK modeling was performed using NONMEM software on log-transformed serum digoxin data. The best structural covariate-free model was a linear 2-compartment model with an exponential error model for intersubject variability and an additive model for intrasubject variability. Serum creatinine (SCR) was a significant covariate for clearance. The final population PK parameters were CL (L/h) = 0.388 - [0.78 x (SCR-0.6)], V1 (L/kg) = 1.38, Q (L/h/kg) = 0.48, V2 (L/kg) = 9.11, where CL is the total body clearance, V1 and V2 are the apparent volumes of distribution in the central and peripheral compartments, and Q is intercompartment clearance. A bootstrap resampling for internal validation achieved excellent agreement with the original data sets for PK parameters. In conclusion, 2 points of digoxin concentration allow good regression analysis for clearance-covariate relationship. The inclusion of SCR into the final model might allow better selection of initial maintenance dose of the drug. A prospective study on larger sample size of pediatric patients is recommended for clinical validation of the final model.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Cardiotônicos
/
Monitoramento de Medicamentos
/
Digoxina
/
Insuficiência Cardíaca
Tipo de estudo:
Observational_studies
Limite:
Adolescent
/
Child
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Child, preschool
/
Female
/
Humans
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Infant
/
Male
País/Região como assunto:
Africa
Idioma:
En
Ano de publicação:
2005
Tipo de documento:
Article