Population pharmacokinetics analyses of rifampicin in adult and children populations: A systematic review.

Aims: Rifampicin has become an essential component as the first-line therapy for pulmonary tuberculosis (PTB). Several population pharmacokinetic (PK) studies on rifampicin in adult and child populations have been studied previously, therefore the aims of the systematic review were (i) to summarize the relevant published studies and significant covariates that influence the PK of rifampicin across different populations, and (ii) to identify any knowledge gap that requires additional research in the future.

Methods: A total of 121 relevant population PK articles were systematically identified using PubMed and Scopus from inception to October 2021. Review articles, in-vitro and physiological methods, animal studies and noncompartmental analysis were excluded.

Results: Nineteen studies, of which 16 involved adults, two involved children, and one involved both adults and children, were included in the review. The structural model of rifampicin can be described as one compartment with a transient compartment absorption model and first-order elimination in most of the studies. Pharmaceutical formulation, body weight, gender, pregnancy status, diabetes and nutritional supplementation were found to be the significant covariates that affect the PK parameters. External validation of the developed PK model was only conducted in two studies.

Conclusions: The source of variability for PK parameters of rifampicin remains inconsistent and poorly understood even though there were many potential covariates investigated in the selected studies. Exploring other possible factors and implementing a strict sampling strategy by considering the induction effects might uncover precise and reliable information. Furthermore, external validation should be frequently conducted to produce better predictability of model performance.