[The impact of different renal function measuring methods on the dosages of meropenem, piperacillin/tazobactam and cefepime in critically ill patients].
OBJECTIVE
Assesment of dosage deviations of three ss-lactam antibiotics eliminated through the kidneys (meropenem, piperacillin/tazobactam and cefepime) by comparison of two prediction formulae, Cockroft-Gault (CG) and Modification of Diet in Renal Disease (MDRD) with 24 h urinary creatinine clearance (CrCl(24h)), as a reference method.


METHODS
125 samples of 61 critically ill patients (each one with CG, MDRD y CrCl(24h) values) were classified in one of the five stages of the National Kidney Foundation (NKF) according to CrCl(24h). Dosage discrepancies for each antibiotic based on CG y MDRD were studied in reference to CrCl(24h) by percentage agreement and weighted kappa. At each of the NKF stages, daily dosage differences (Delta=DosisCG-DosisCrCl(24h); Delta=DosisMDRD-DosisCrCl(24h)) and percentage of samples with dosage discrepancies by CG and MDRD in reference to CrCl(24h) were calculated.


RESULTS
There were no statistically significant differences between the two prediction formulae in respect to CrCl(24h), achieving good degrees of concordance. Deviation percentages fluctuated between 15.2% and 28% and occurred mainly by underdosing on stages 1 and 2 and by overdosing on stages 4 and 5.


CONCLUSIONS
The two renal function prediction formulae can be indistinctly used to optimize the ss-lactam antibiotics dose regimen, CG being the easiest one.
Diego del Río
E
E
Servicio de Farmacia, Hospital Clinic, Barcelona, España. ediegode@gmail.com
Soy Muner
D
D
Gratacós Santanach
L
L
Ribas Sala
J
J
D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000652:urine*; D000077723:Cefepime; D002511:Cephalosporins / Q000008:administration & dosage* / Q000652:urine*; D016638:Critical Illness; D006801:Humans; D007677:Kidney Function Tests / Q000379:methods*; D000077731:Meropenem; D010397:Penicillanic Acid / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000652:urine; D010878:Piperacillin / Q000008:administration & dosage / Q000652:urine; D000077725:Piperacillin, Tazobactam Drug Combination; D012189:Retrospective Studies; D013845:Thienamycins / Q000008:administration & dosage* / Q000652:urine*
D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D013845:Thienamycins; D000077725:Piperacillin, Tazobactam Drug Combination; D000077723:Cefepime; D010397:Penicillanic Acid; D000077731:Meropenem; D010878:Piperacillin