Meropenem Pharmacodynamics and Neurotoxicity in Acute Kidney Injury

Pharmacodynamic Targets

• For beta‑lactam antibiotics such as meropenem, optimal efficacy requires the free drug concentration to remain above the minimum inhibitory concentration (MIC) for 40 %–100 % of the dosing interval. 1

Neurotoxicity Risk

• In patients with acute kidney injury, meropenem trough concentrations > 45 mg/L are associated with an increased risk of neurotoxicity, particularly seizures. 1
• This neurotoxicity risk is amplified in the presence of renal dysfunction because drug accumulation is more likely. 1
• Meropenem has a moderate pro‑convulsive activity (≈ 16 % of that of penicillin G at comparable dosing), which is clinically relevant. 1

Dosing Optimization in Critical Illness

• Extended infusions (≈ 3 hours) or continuous infusions are recommended for critically ill patients or when treating pathogens with higher MICs, as they improve the likelihood of achieving the required pharmacodynamic target. 1
• Therapeutic drug monitoring of meropenem trough levels should be employed to identify concentrations that may predispose to neurotoxicity, especially after multiple doses. 1

Meropenem Pharmacodynamic Targets and Dosing in Critical Illness

Pharmacodynamic Targets

• In critically ill patients with severe infections, maintaining the free meropenem concentration above the pathogen MIC for 100 % of the dosing interval (fT > MIC) is associated with optimized clinical outcomes. 2

Loading Dose Recommendations

• A loading dose of meropenem should be administered to all critically ill patients to achieve rapid therapeutic concentrations; this loading dose is not altered by renal impairment, whereas subsequent maintenance doses must be adjusted according to renal function. 2

Neurotoxicity Considerations

• Meropenem possesses moderate pro‑convulsive activity, estimated at ≈ 16 % of the convulsive potency of penicillin G, which contributes to its seizure risk profile. 3