Factors Influencing Pharmacokinetic/Pharmacodynamic Index of Meropenem in Critically Ill Patients

Abstract There is a growing consensus that, in critically ill patients, meropenem dosing should aim to achieve 100% fT > MIC. The primary objective of our study was to evaluate the frequency of meropenem underdosing—considering its widespread use in this population—and to identify factors associated with such underdosing. This prospective, cross-sectional study included two groups of critically ill patients: a control group, comprising patients who received optimal meropenem dosing (100% fT > MIC), and a case group, consisting of patients who were underdosed (fT > MIC < 100%). A validated high-performance liquid chromatography (HPLC) method was employed to measure meropenem concentrations in plasma. The effects of various independent and confounding variables on the dichotomous dependent variable were assessed using univariate and multivariate logistic regression analyses. We recruited a total of 63 critically ill patients. The results of our study demonstrated that the majority of critically ill patients (n = 52; 82.5%) received an adequate meropenem dose, achieving fT > MIC of 100%, whereas 11 patients (17.5%) were underdosed, with fT > MIC below 100%. Finally, Acinetobacter spp. and Pseudomonas aeruginosa, as causative pathogens of bacterial infections, were identified as significant risk factors for meropenem underdosing in critically ill patients. Clinicians should exercise caution when selecting the meropenem dosage for critically ill patients with infections caused by Acinetobacter spp. and Pseudomonas aeruginosa.