Lack of predictability of chloramphenicol toxicity in paediatric patients

Successful treatment of vancomycin-resistant Enterococcus faecium ventriculitis with combined intravenous and intraventricular chloramphenicol in a newborn

Vancomycin-resistant Enterococcus faecium (VRE) infection is a rare event in paediatric patients and often occurs under immunosuppression or after surgical intervention. We report what we believe to be the first paediatric case of ventriculitis due to VRE (in a 2-month-old infant) to be successfully treated with combined intravenous (i.v.) and intraventricular chloramphenicol after failure of i.v. linezolid and intraventricular gentamicin.

Relationship between clinical and biologic variables and chloramphenicol pharmacokinetic parameters in pediatric patients with sepsis

OBJECTIVE

To evaluate the influence of several clinical and biologic factors on the disposition kinetics of oral chloramphenicol in pediatric patients and to determine the usefulness of this information to predict chloramphenicol serum concentrations.

STUDY DESIGN

The clinical, biologic, and pharmacokinetic data of 30 consecutive pediatric patients diagnosed with sepsis and admitted to a tertiary care center were analyzed retrospectively. The patients were randomly assigned to a study group and a validation group. The model was developed by a three-step approach involving Bayesian estimation of pharmacokinetic parameters, selection of covariates by principal component analysis, and final selection by stepwise multiple linear regression. The model was tested in the study group and compared with a general population model using a prediction error analysis.

RESULTS

Regression analysis revealed that weight, albumin, and white blood cell (WBC) count were the most important determinants for chloramphenicol distribution volume, whereas age, WBC count, and serum creatinine were the most important determinants for chloramphenicol clearance. The performance of the constructed population model improved significantly in terms of both bias and precision compared with the general model when tested in the validation group.

CONCLUSIONS

Clinical and biologic factors may significantly influence chloramphenicol's disposition in pediatric patients with sepsis and therefore should be considered in programming dosage regimens.

Therapeutic drug monitoring in pediatrics: a need for improvement

Therapeutic drug monitoring (TDM) is practiced for a number of frequently used drugs in infants and children. It is believed that monitoring drug levels will increase the probability of a therapeutic response and minimize the probability of adverse drug sequelae. Dose adjustments are based on measured drug levels interpreted relative to published therapeutic ranges which may or may not reflect the true relationship with either therapeutic or adverse effects. Potential errors derive from many sources, some amenable to solutions based on current knowledge, others awaiting improved understanding of the causes and consequences of unreliable therapeutic ranges.

Variability in clinical pharmacology of drugs in children

Numerous factors can lead to variability in pharmacokinetics, pharmacodynamics, efficacy, and toxicity of drugs in infants and children. These may include age, race or genetic status, organ function, underlying disease(s), drug formulation, concomitant drugs, and compliance with therapy. Further research is needed to clarify the mechanisms for variability in drug response to achieve optimal use of drugs in paediatric patients.