Factors associated with meropenem pharmacokinetic/pharmacodynamic target attainment in septic critically ill patients treated with extended intermittent infusion or continuous infusion

Objectives: The use of extended intermittent infusion (EII) or continuous infusion (CI) of meropenem is recommended in intensive care unit (ICU) patients, but few data comparing these two options are available. This retrospective cohort study was conducted between 1 January 2019 and 31 March 2020 in a teaching hospital ICU. It aimed to determine the meropenem plasma concentrations achieved with CI and EII.

Methods: The study included septic patients treated with meropenem who had one or more meropenem plasma trough (Cmin) or steady-state concentration (Css) measurement(s), as appropriate. It then assessed the factors independently associated with attainment of the target concentration (Cmin or Css ≥ 10 mg/L) and the toxicity threshold (Cmin or Css ≥ 50 mg/L) using logistic regression models.

Results: Among the 70 patients analysed, the characteristics of those treated with EII (n = 33) and CI (n = 37) were balanced with the exception of estimates glomerular filtration rate (eGFR): median 30 mL/min/m² (IQR 30, 84) vs. 79 mL/min/m² (IQR 30, 124). Of the patients treated with EII, 21 (64%) achieved the target concentration, whereas 31 (97%) of those treated with CI achieved it (P < 0.001). Factors associated with target attainment were: CI (OR 16.28, 95% CI 2.05-407.5), daily dose ≥ 40 mg/kg (OR 12.23, 95% CI 1.76-197.0; P = 0.03) and eGFR (OR 0.98, 95% CI 0.97-0.99; P = 0.02). Attainment of toxicity threshold was associated with daily dose > 70 mg/kg (OR 35.5, 95% CI 5.61-410.3; P < 0.001).

Conclusion: The results suggest the use of meropenem CI at 40-70 mg/kg/day, particularly in septic ICU patients with normal or augmented renal clearance.