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Table 2 Summary of time-dependent antibiotics and proposed targets for TDM dose adjustments

From: How do we use therapeutic drug monitoring to improve outcomes from severe infections in critically ill patients?

PK/PD index Antibiotics PK/PD thresholds associated with optimal bacterial killing and/or clinical outcome PK/PD threshold for potential toxicity
fT>MIC Beta-lactams Predominantly 100% fT>MIC for TDM purposes [22] Has not been clearly defined. Thresholds from 100% fT>6xMIC to 100% fT>10xMIC has been arbitrarily chosen by some centres [22]
Penicillins 30% fT>MIC (bacteriostatic)
50% fT>MIC (bactericidal – animal model and clinical studies in non-critically ill patients) [154]
Cephalosporins 40–70% fT>MIC (animal models) [154]
100% fT>MIC up to 100% fT>4–5xMIC (optimal clinical outcome observed for cefepime and ceftazidime) [18, 37]
Carbapenems 20% fT>MIC (bacteriostatic)
40% fT>MIC (bactericidal)
100% fT>5xMIC (optimal clinical outcome observed for meropenem) [155]
Monobactams 50% fT>MIC (bactericidal)
Linezolid >85% fT>MIC[125, 156]