BACKGROUND: Suboptimal exposure to antituberculosis drugs has been associated with unfavourable treatment outcomes. We aimed to investigate estimates and determinants of first-line antituberculosis drug pharmacokinetics in children and adolescents at a global level.
METHODS: We systematically searched MEDLINE, Embase, and Web of Science (1990-2021) for pharmacokinetic studies of first-line antituberculosis drugs in children and adolescents. Individual patient data were obtained from authors of eligible studies. Summary estimates of total/extrapolated area under the plasma concentration-time curve (AUC0-24) and peak plasma concentration (Cmax) were assessed with random-effects models, normalised with current WHO-recommended paediatric doses. Determinants of AUC0-24 and Cmax were assessed with linear mixed-effects models.
RESULTS: Of 55 eligible studies, individual patient data were available for 39 (71%), including 1628 participants from 12 countries. Geometric means (95% CIs) of steady-state AUC0-24 were summarised for isoniazid (18.7 [15.5-22.6] h·mg·L-1), rifampicin (34.4 [29.4-40.3] h·mg·L-1), pyrazinamide (375.0 [339.9-413.7] h·mg·L-1), and ethambutol (8.0 [6.4-10.0] h·mg·L-1). Our multivariate models indicated that younger age (especially <2 years) and HIV-positive status were associated with lower AUC0-24 for all antituberculosis drugs, while severe malnutrition was associated with lower AUC0-24 for isoniazid and pyrazinamide. N-acetyltransferase 2 rapid acetylators had lower isoniazid AUC0-24 and slow acetylators had higher isoniazid AUC0-24 than intermediate acetylators. Determinants of Cmax were generally similar to those for AUC0-24.
CONCLUSION: This study provides the most comprehensive estimates of plasma exposures to first-line antituberculosis drugs in children and adolescents. Key determinants of drug exposures were identified. These may be relevant for population-specific dose adjustment or individualised therapeutic drug monitoring.