Therapeutic Drug Monitoring of Vancomycin at Queen Sirikit Heart Center of the Northeast

The purpose of this study was to investigate the therapeutic drug monitoring (TDM) of vancomycin at Queen Sirikit Heart Center of the Northeast, Thailand about the patients’ characteristics, indicators of vancomycin, frequency of TDM service, vancomycin levels and pharmacokinetic parameters of vancomycin. The study was retrospective descriptive study in patients admitted at Queen Sirikit Heart Center of the Northeast, Thailand aged over 15 years old and received vancomycin injection during 1 June 2005 to 31 May 2007. There were 43 patients received TDM services in that time but only 27 patients were recruited in this study. The median of age, weight, serum creatinine, blood urea nitrogen and creatinine clearance were 51.00 years old, 51.20 kg, 1.40 mg/dl, 24.30 mg/dl, and 44.41 ml/min, respectively. The indications of vancomycin were for treating infection of heart, skin and heart and lung in 24, 2 and 1 patients, respectively. Fifty six of 80 TDM services could be assessed. Maximum concentrations were within and beyond therapeutic range for 19 times (33.93%) and 37 times (66.07%), respectively. Minimum concentrations were within and beyond therapeutic range for 30 times (53.57%) and 26 times (46.43%), respectively. Pharmacists had provided 39 recommendations to modify the dosage regimen of vancomycin and 34 (87.18%) recommendations had been responded by physicians as absolute following. Twenty three vancomycin level were rechecked after physician response and they became within and beyond therapeutic range for 11 and 12 times, respectively. The median of pharmacokinetic parameters; volume of distribution, elimination rate constant, half life, and vancomycin clearance were 0.7800 l/kg, 0.0545 h ⁻ ¹, 12.7237 h, and 35.8253 ml/min, respectively. In conclusion, the therapeutic drug monitoring of vancomycin was useful for dosage adjustment in individual patient for effectiveness of treatment outcome and to prevent adverse drug reaction.