Abstract:

Objective To evaluate the application of the peak plasma concentration, which were plasma concentrations of rifampicin (RFP) at 2 h (C_{2 h}) and 6 h (C_{6 h}) post-dose in newly diagnosed active tuberculosis patients, in guidance for clinical management. Methods According to the inclusion criteria, 148 active tuberculosis patients from the Third People’s Hospital of Shenzhen between November 2016 and November 2017 were included, and their C_{2 h} and C_{6 h} were monitored by HPLC one week after taking rifampicin. Based on international rifampicin plasma C_max (8-24 μg/ml), plasma concentration, malabsorption and delayed absorption of the two time points were analyzed using SPSS 19.0. Gender, age, BMI, rifampicin dosage, concurrent diabetes, concurrent hepatitis B virus and serum albumin levels etc. of the low C_max group (those who were below the standard range) and the normal C_max group (those who in the standard range) were described as “ \bar{x} ±s” and compared by t test. Categorical variables were compared by χ ² test and P<0.05 was considered statistically significant. Results C_{2 h} was below the standard range in 24.3% (36/148) of all the patients;however, among them, 36.1% (13/36) patients reached target C_max (8-24 μg/ml) at C_{6 h}; totally, C_{6 h} of 84.5% (125/148) patients reached the target C_max, the rate of delayed absorption was 10.4% (13/125). There were no statistical differences between low C_max group and the normal C_max group in gender (male, 60.9% (14/23) vs. 68.8% (86/125), χ ²=0.558, P=0.455), age ((36.9±4.2) years vs. (38.2±3.5) years, t=-1.585, P=0.115), BMI ((21.5±4.0) vs. (22.9±3.7), t=-1.647, P=0.102), rifampicin dosage of 450 mg/d (60.9% (14/23) vs. 43.2% (54/125), χ ²=2.442, P=0.118), concurrent diabetes (8.7% (2/23) vs. 22.4% (28/125), χ ²=2.257, P=0.166), complicated with hepatitis B virus (4.3% (1/23) vs. 9.6% (12/125), χ ²=0.669, P=0.694), and serum albumin levels ((42.3±4.4) g/L vs. (40.9±3.2) g/L, t=1.457, P=0.157). Conclusion Monitoring rifampicin C_max at two time points could reflect the absorption of rifampicin in the body more accurately. However, there was no influence factors been found, and expanded sample for further research would be warranted in the future.

Key words: Rifampin, Therapeutic drug monitoring (TDM), Dose-response relationship,drug, Pharmacokinetics, Outcome assessment (health care)