- Article
14 Pages
Tuberculosis (TB) patients with comorbidities may have altered rifampicin pharmacokinetics (PK), particularly in sub-Saharan Africa. This can affect treatment response and suggests a role for therapeutic drug monitoring (TDM) in identifying suboptimal exposure. We describe the rifampicin PK in Tanzanian TB patients with HIV, diabetes mellitus (DM), or malnutrition. Participants were enrolled and followed for six months, with PK sampling at baseline and at week 2. All received standard rifampicin, isoniazid, pyrazinamide, and ethambutol. Plasma concentrations were measured via high-performance liquid chromatography (HPLC) before dosing and at 2 ± 1, 5 ± 1, and 12 ± 3 h post-dose. The area under the concentration–time curve to the last measured concentration (AUC0-last) and the peak plasma concentration (Cmax) were derived by non-compartmental analysis. Treatment outcomes were assessed at 6 months using WHO definitions. Of 40 participants (median age 45 years), 34 had a valid PK sample at both visits. Exposure declined between visits in most participants, but magnitude and direction change differed by comorbidity group. The largest median decline occurred in combined HIV–malnutrition (−23.7% for Cmax, and −29.8% AUC0-last), whereas the malnutrition-only group showed no consistent direction, and some of its participants had higher exposure at week 2. In the adjusted mixed-effects model, visit was the only variable whose confidence interval excluded zero (AUC0-last −22.6%, 95% CI, −28.5%, to −16.2%; Cmax −20.1%, 95% CI, −25.5%, −14.3%); HIV, malnutrition, their interaction, age, sex, and mid-upper arm circumference (MUAC) showed no clear association with exposure. Six-month outcomes differed by comorbidity, with deaths concentrated among HIV-positive participants, particularly those who were also malnourished. These findings support combining TDM with individualized dosing, including model-informed precision dosing delivered through clinical decision support systems to optimize rifampicin exposure in high-risk groups.
Trop. Med. Infect. Dis.
4 November 2026





