Abstract
Introduction
Population modelling using mixed effects models provides a means to study variability in paediatric drug responses among individuals representative of those in whom the drug will be used clinically.
Discussions
Explanatory covariates explain the predictable part of the between-individual variability. Growth and development are two major aspects of children not seen in adults. These aspects can be investigated by using size and age as covariates. Problems attributable to co-linearity can be approached by using size as the first covariate. Size standardisation is achieved using allometric scaling, a mechanistic approach that has a strong theoretical and empirical basis. Age is used to describe the maturation of clearance. The quantitative models (linear, exponential, first-order, variable slope sigmoidal) used to describe this maturation process vary depending on the span of the ages under investigation. Measures of response are not always straightforward and can be more difficult to quantify in children.
Conclusion
Covariate investigation in children is improving the understanding of developmental aspects of drug disposition and effects in the paediatric population, ultimately leading to more effective use of medications.
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Abbreviations
- BMR:
-
Basal metabolic rate
- BSA:
-
Body surface area
- CL:
-
Clearance
- CLcr:
-
Creatinine clearance
- CPR:
-
Creatinine production rate
- GFR:
-
Glomerular filtration rate ka; absorption rate constant
- ln:
-
Natural logarithm
- NONMEM:
-
Nonlinear mixed effects model
- PD:
-
Pharmacodynamics
- PK:
-
Pharmacokinetics
- PMA:
-
Postmenstrual age
- PNA:
-
Postnatal age
- PWR:
-
Allometric power exponent
- Tabs:
-
Absorption half time
- TDM:
-
Therapeutic drug monitoring
- V:
-
Volume of distribution
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Acknowledgement
The clinical research of K. Allegaert is supported by the Fund for Scientific Research, Flanders (Belgium) by a Clinical Doctoral Grant (A 6/5–KV–G 1).
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Anderson, B.J., Allegaert, K. & Holford, N.H.G. Population clinical pharmacology of children: modelling covariate effects. Eur J Pediatr 165, 819–829 (2006). https://doi.org/10.1007/s00431-006-0189-x
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DOI: https://doi.org/10.1007/s00431-006-0189-x