Population Pharmacokinetics of Moxifloxacin in Children.

BACKGROUND/OBJECTIVE: Moxifloxacin is a fluoroquinolone that is commonly used in adults, but not children. Certain clinical situations compel pediatric clinicians to use moxifloxacin, despite its potential for toxicity and limited pharmacokinetics (PK) data. Our objective was to further characterize the pharmacokinetics of moxifloxacin in children.

METHODS

We performed an opportunistic, open-label population PK study of moxifloxacin in children < 18 years of age who received moxifloxacin as part of standard care. A set of structural PK models and residual error models were explored using nonlinear mixed-effects modeling. Covariates with known biological relationships were investigated for their influence on PK parameters.

RESULTS

We obtained 43 moxifloxacin concentrations from 14 participants who received moxifloxacin intravenously (n = 8) or orally (n = 6). The dose of moxifloxacin was 10 mg/kg daily in participants ≤ 40 kg and 400 mg daily in participants > 40 kg. The population mean clearance and mean volume of distribution were 18.2 L/h and 167 L, respectively. The oral absorption was described by a first-order process. The estimated extent of oral bioavailability was highly variable (range 20-91%). Total body weight was identified as a covariate on clearance and volume of distribution, and substantially reduced the random unexplained inter-individual variability for both parameters. No participants experienced suspected serious adverse reactions related to moxifloxacin.

CONCLUSION

These data add to the existing literature to support use of moxifloxacin in children in certain situations; however, further prospective studies on the safety and efficacy of moxifloxacin are needed.