[Comparative study on the pharmacokinetics of rifampicin between the old and middle-aged tuberculosis patients]

Area of Science:

• Pharmacology
• Clinical Pharmacy
• Tuberculosis Research

Background:

• Rifampicin (RFP) is a cornerstone antibiotic for tuberculosis (TB) treatment.
• Understanding RFP pharmacokinetics in diverse age groups, including the elderly, is crucial for optimizing TB therapy.
• Age-related physiological changes can potentially alter drug metabolism and elimination.

Purpose of the Study:

• To investigate and compare the pharmacokinetics of oral rifampicin in elderly versus middle-aged tuberculosis patients.
• To determine if age significantly impacts key pharmacokinetic parameters of rifampicin.
• To assess the suitability of standard rifampicin dosing for older TB patients.

Main Methods:

• A comparative pharmacokinetic study involving 16 tuberculosis patients (8 elderly, 8 middle-aged).
• Oral administration of a 450 mg dose of rifampicin (RFP).
• High-performance liquid chromatography (HPLC) was used for RFP plasma concentration analysis.
• One-compartment pharmacokinetic modeling was applied to plasma concentration-time data.

Main Results:

• Plasma concentration-time curves for both groups were best described by a one-compartment model.
• Key pharmacokinetic parameters, including half-life (t 1/2), maximum concentration (Cmax), volume of distribution (vd), and clearance (CL), showed no statistically significant differences between elderly and middle-aged groups (P > 0.05).
• Specific parameters: t 1/2 (2.39 ± 0.66 vs 3.84 ± 1.91 h), Cmax (14.56 ± 6.45 vs 9.83 ± 2.55 µg/ml), vd (0.43 ± 0.11 vs 0.67 ± 0.15 L/kg), CL (0.14 ± 0.03 vs 0.13 ± 0.06 L·h⁻¹·kg⁻¹).

Conclusions:

• The pharmacokinetics of a 450 mg oral dose of rifampicin do not significantly differ between elderly and middle-aged tuberculosis patients.
• Standard oral rifampicin dosing appears to be safe and effective for aging tuberculosis patients.
• This finding supports the use of 450 mg/day rifampicin in the elderly population for tuberculosis treatment.