Therapeutic drug monitoring of vancomycin and meropenem: Illustration of the impact of inaccurate information in dose administration time
Maria Swartling, Thomas Tängdén, Miklós Lipcsey, Siv Jönsson, Elisabet I. Nielsen
Abstract
To illustrate the impact of errors in documented dose administration time on therapeutic drug monitoring (TDM)-based target attainment evaluation for vancomycin and meropenem, and explore the influence of drug and patient characteristics, and TDM sampling strategies. Bedside observations of errors in documented dose administration times were collected. Population pharmacokinetic simulations were performed for vancomycin and meropenem, evaluating different one- and two-sampling strategies for populations with estimated CLcr 30, 80 or 130 mL/min. The impact of errors was evaluated as the proportion of individuals falsely considered to have reached the target. Of 143 observed dose administrations, 97% were given within ±30 min of the documented time. For vancomycin, a +30 min error was predicted to result in a 0.1-3.9 percentage point increase of cases falsely evaluated as reaching AUC24/MIC >400, with the largest increase for patients with augmented renal clearance and peak and trough sampling. For meropenem, the same error magnitude resulted in a 1.3-6.4 and 0-20 percentage point increase of cases falsely evaluated as reaching 100% T>MIC, and 50% T>MIC, respectively. Overall, mid-dose and trough sampling was most favourable for both antibiotics. For vancomycin, simulations indicate that TDM-based target attainment evaluation is robust with respect to the observed errors in dose administration time of ±30 min; however, impact of potential clinical importance was noted in patients with augmented renal clearance. For meropenem, extra measures to promote correct documentation are warranted when using TDM, since the impact of errors was evident already at normal renal function.