Optimal dose of meropenem for the treatment of neonatal sepsis: Dosing guideline variations and clinical practice deviations

Aims Meropenem is increasingly used to treat neonatal sepsis. There are several guidelines recommending different dosing regimens of meropenem in neonates. Furthermore, deviations from these guidelines regularly occur in daily clinical practice. Therefore, the current study aimed to evaluate the variations of meropenem dosing guidelines and compare the difference between guideline and clinical practice in terms of the probability of target attainment. Methods This study is based on a population pharmacokinetic model. After defining the predictive performance of the model, Monte Carlo simulations were used to calculate the probability of target attainment of the currently existing dosing guidelines of meropenem and their use in daily clinical practice. Results Two guidelines and two labels were included in the Monte Carlo simulations. For 70% fT(>MIC) (fraction of time when the free meropenem concentration exceeded the minimum inhibitory concentration during the dosing interval), the probability of target attainment of four recommended doses ranged from 59% to 88% (MIC = 2 mg center dot L-1) and from 17% to 47% (MIC = 8 mg center dot L-1). At the clinical practice evaluation, only 20% of patients attained target exposure for the MIC of 8 mg center dot L-1 with 70% fT(>MIC), which was much less than those found in the Food and Drug Administration labels (40%). Conclusion This model-based population pharmacokinetics simulation showed that improper guidelines and/or clinical practice deviations will result in low probability of target attainment for patients infected with resistant bacteria and critically ill patients. It is important to develop and adhere to evidence-based and clinically pragmatic guidelines.