Therapeutic Drug Monitoring of Vancomycin

Wie, Seong Heon; Kim, Sang Il; Kim, Yang Ree; Bae, Sung Mi; Hong, Kyoung Ja; Ra, Hyun Oh; Kang, Moon Won

Abstract

BACKGROUND
Vancomycin assay was performed to evaluate the clinical significance of therapeutic drug monitoring (TDM) of vancomycin and to compare pharmacokinetic parameters of vancomycin in our patients with population pharmacokinetic parameters.
METHODS
In seventy-eight patients (45 males, 33 females), vancomycin serum concentrations were measured by fluorescence polarization immunoassay. At steady-state, peak levels were obtained one hour postinfusion, and trough levels were obtained just before a next dose. And also predicted serum vancomycin levels were determined by CAPCIL program in all subjects and compared with measured values, respectively. All patients were divided into two groups. Sixty-two patients in group I had a creatinine concentration in serum of < or =1.2 mg/dL and sixteen patients in group IIhad abnormal renal function as defined by a creatinine concentration in serum of >1.2 mg/dL. Follow-up second vancomycin concentrations were measured in 22 of 78 patients several days after initial TDM and were compared with initial TDM results.
RESULTS
Mean values of peak and trough vancomycin concentration were 30.1 and 10.4, and 37.3 and 14.5 microgram/mL in groups I, and II, respectively. Predicted mean values of those were 26.3 and 9.2, and 28.2 and 7.8 microgram/mL in groups I, and II, respectively. Statistically significant differences between predicted and measured values in peak levels of group I,and IIand in trough level of group IIwere observed (P<0.01). Dose modification were required in 13 (21%) of 62 patients with normal renal function, and in 9 (56%) of 16 patients with abnormal renal function. Among 79 paired samples with a trough value below 15 mg/L, there were no peaks greater than 40 mg/L except two samples.
CONCLUSION
Significant differences were noted between predicted and measured serum vancomycin concentrations and so TDM of vancomycin is needed to obtain effective dose and interval of vancomycin. More data about measured peak and trough values should be collected to establish pharmacokinetic parameters of vancomycin in Korean population.