OVERVIEW
- there is little published data to guide dosing of antibiotics in RRT and the critically ill.
- therefore we must use first principles and utilize therapeutic drug monitoring if available.
CONSIDERATIONS
Properties of the antibiotic
- size of molecule
- charge
- solubility
Pharmaokinetics of drug
- how much will be dialysed
- Vd
- clearance
- protein binding
Pharmacodynamics of drug
- what concentrations need to be achieved to be effective
- kill characteristics of drug:
– peak dose/concentration dependent (aminoglycosides)
– time above MIC (beta lactams)
– time and concentration dependent (AUC -> quinlones)
Type and settings of RRT
- mode: CVVDH, CVVHF, CVVDHF
- CVVHD: molecular weight, blood flow rate, dialysate flow rate
- CVVHF: ultrafiltrate flow rate
- blood flow rate
- pre vs post filter dilution
Site of infection/tissue penetration ability of drug
Toxicity of high drug levels
Residual or recovery of intrinsic renal function
RRT prescription compliance
Availability of Theraputic Drug Monitoring
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