Research Information System
15th Febrile Neutropenia Symposium Online , 15 - 16 March 2025, pp.1, (Summary Text)
Background: Meropenem is a beta-lactam antibiotic with a broad spectrum of activity. It exhibits
time-dependent antimicrobial activity. The recommended pharmacokinetic/pharmacodynamic
(PK/PD) index of meropenem is the unbound plasma meropenem concentrations above
the minimum inhibitory concentration (MIC) (fT>MIC) at least 40% of the time between dosing
intervals. In more severe infections, 100% fT>MIC may be required.
Aim: The aim of this study was to define meropenem trough levels in adult patients and analyze the
factors that influence meropenem levels. The effect of meropenem concentrations on clinical and
microbiological outcome was also investigated.
Methods: This study was conducted as a retrospective cohort study in a university hospital
(Hacettepe University Hospitals, Ankara, Türkiye) between April 2022-December 2024. Venous blood
was obtained from patients at least 24 hours after the initiation of treatment. Trough concentrations
were evaluated in patients. According to the literature, meropenem PK/PD index was accepted as
100%fT>MIC and 100%fT>4*MIC targets.
Results: 331 patients were enrolled in this study. A total of 543 meropenem levels were measured in
386 treatment episodes. The median age (min-max) of the patients was 64 (18-95) years and 53.8%
male. Thirty-four (6.3%) of the patients were on renal replacement therapy. The most common
indication for meropenem treatment was pneumonia. Prolonged infusions were used in the 50.6%
(n=275) of the maintenance dose. The median duration of meropenem treatment (days), median
(min-max) was 9 (1-184). Meropenem dose was found appropriate in 492 (90.6%) patients in the last
24 hours according to renal functions. Blood cultures were positive in 20.1% of the treatment
episodes. Carbapenem resistance was detected in 60.6 of gram-negative bacilli isolated in different
cultures. Meropenem was used as monotherapy in 15.8% of the treatment episodes. The most
common antibiotic combination against documented or suscepted gram negative bacilli infections
were meropenem plus polymyxin B or colistin followed by amikacin. Clinical cure was observed in
239 (71.13%) treatments and microbiologic cure in 107 (78.10%) treatments. MIC level was
determined in 103 patients. For the remaining patients, MIC WCS (ECOFF) was determined as 4 mg/L.
For PK-PD index 100% fT>MIC (p<0.001) and 100% fT>4*MIC (p=0.004), the proportion of treatments
reaching the target was higher in the continuous infusion and loading dose 6 g/24 h group (p<0.001).
As GFR increased, the rate of reaching the target decreased (p<0.001). A significant difference was
found in terms of clinical cure for sepsis (p<0.001). There was a significant difference for achieving
100% fT>MIC in treatment episodes with and without microbiological cure (p<0.001).