Never reduce loading doses for renal function. Adjust maintenance doses to measured or estimated clearance, recognising that creatinine is unreliable in unstable AKI, that CRRT removes many antibiotics, and that young septic or trauma patients often clear drugs faster than normal.
At the bedside
Timed steps- 1
Full dose
LoadLoading dose depends on volume of distribution, not clearance – give the full dose in AKI and on RRT.
- 2
Clearance
EstimateCockcroft-Gault or measured 8-24 h urinary creatinine clearance; eGFR equations assume steady state and mislead in changing AKI.
- 3
Don't under-dose
Early sepsis AKIMany AKIs resolve within 48 h; for wide-therapeutic-index antibiotics (beta-lactams) delay renal down-adjustment for the first 24-48 h.
- 4
Account for removal
CRRTEffluent 25 mL/kg/h gives roughly 25-35 mL/min of clearance for small, unbound drugs; dose accordingly and use TDM.
- 5
Recognise
ARCMeasured CrCl > 130 mL/min (young, trauma, sepsis, TBI) leads to sub-therapeutic beta-lactam and vancomycin levels: higher or more frequent doses, prolonged infusions, TDM.
- 6
Prolonged infusion
Beta-lactamsMeta-analysis: prolonged infusion lowered 90-day mortality; BLING III alone was not significant. Consider extended (3-4 h) or continuous infusion after a loading dose.
Maintenance in AKI/CRRT
Vancomycin
- Dose
- Full loading dose, then redose by levels (e.g. when level < 15-20 mg/L on intermittent HD; ~15 mg/kg every 24 h on CRRT as a starting point)
Calculators for this topic
References
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Renal dose adjustment
Step 1 of ~4
Give full loading dose
Based on Matzke GR, Aronoff GR, Atkinson AJ, et al; Udy AA, Roberts JA, Lipman J. Educational use; follow local protocol.
Evidence
- KDIGO 2011 update (Matzke): framework for dosing in AKI and CKD.
- Udy 2011: ARC common in critically ill; sub-therapeutic levels.
- BLING III 2024: 7031 patients, continuous vs intermittent beta-lactam; 90-day mortality difference not significant.
- Abdul-Aziz 2024 meta-analysis: prolonged infusion associated with lower 90-day mortality.
Controversies
- CRRT antibiotic dosing tables vary widely; therapeutic drug monitoring is limited to vancomycin and aminoglycosides in most Indian ICUs.
🇮🇳 India notes
- Beta-lactam TDM is rarely available; extended infusions of meropenem (e.g. 1-2 g over 3 h every 8 h) are a pragmatic option.
References
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Test yourself
Module quiz · score 70% to complete the module
Educational reference for trained clinicians. Check doses against your hospital protocol and the patient in front of you.