Assessment of body mass-related covariates for rifampicin pharmacokinetics in healthy Caucasian volunteers.
Muhammad Bilal, Sami Ullah, Ulrich Jaehde, Christina Trueck, Dario Zaremba, Bertil Wachall, Manfred Wargenau, Bernhard Scheidel, Martin H J Wiesen, Malaz Gazzaz, Chunli Chen, S��ren B��sker, Uwe Fuhr, Max Taubert, Charalambos Dokos
Author Information
Muhammad Bilal: Department I of Pharmacology, Center for Pharmacology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany. muhammad.bilal@uk-koeln.de.
Sami Ullah: Department I of Pharmacology, Center for Pharmacology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany.
Ulrich Jaehde: Department of Clinical Pharmacy, Institute of Pharmacy, University of Bonn, Bonn, Germany.
Christina Trueck: Department I of Pharmacology, Center for Pharmacology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany.
Dario Zaremba: Department I of Pharmacology, Center for Pharmacology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany.
Bertil Wachall: InfectoPharm Arzneimittel Und Consilium GmbH, 64646, Heppenheim, Germany.
Bernhard Scheidel: ACC GmbH Analytical Clinical Concepts, Leidersbach, Germany.
Martin H J Wiesen: Pharmacology at the Laboratory Diagnostics Centre, Faculty of Medicine, University Hospital Cologne, University of Cologne, Therapeutic Drug Monitoring, Cologne, Germany.
Malaz Gazzaz: Pharmaceutical Practices Department, College of Pharmacy, Umm Al-Qura University, Makkah, Saudi Arabia.
Chunli Chen: Department I of Pharmacology, Center for Pharmacology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany.
S��ren B��sker: Department I of Pharmacology, Center for Pharmacology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany.
Uwe Fuhr: Department I of Pharmacology, Center for Pharmacology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany.
Max Taubert: Department I of Pharmacology, Center for Pharmacology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany.
Charalambos Dokos: Department I of Pharmacology, Center for Pharmacology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany.
PURPOSE: Currently, body weight-based dosing of rifampicin is recommended. But lately, fat-free mass (FFM) was reported to be superior to body weight (BW). The present evaluation aimed to assess the influence of body mass-related covariates on rifampicin's pharmacokinetics (PK) parameters in more detail using non-linear mixed effects modeling (NLMEM). METHODS: Twenty-four healthy Caucasian volunteers were enrolled in a bioequivalence study, each receiving a test and a reference tablet of 600 mg of rifampicin separated by a wash-out period of at least 9 days. Monolix version 2023R1 was used for NLMEM. Monte Carlo simulations (MCS) were performed to visualize the relationship of body size descriptors to the exposure to rifampicin. RESULTS: A one-compartment model with nonlinear (Michaelis-Menten) elimination and zero-order absorption kinetics with a lag time best described the data. The covariate model including fat-free mass (FFM) on volume of distribution (V/F) and on maximum elimination rate (Vmax/F) lowered the objective function value (OFV) by 56.4. The second-best covariate model of sex on V/F and Vmax/F and BW on V/F reduced the OFV by 51.2. The decrease in unexplained inter-individual variability on Vmax/F in both covariate models was similar. For a given dose, MCS showed lower exposure to rifampicin with higher FFM and accordingly in males compared to females with the same BW and body height. CONCLUSION: Our results indicate that beyond BW, body composition as reflected by FFM could also be relevant for optimized dosing of rifampicin. This assumption needs to be studied further in patients treated with rifampicin.
