[The impact of different renal function measuring methods on the dosages of meropenem, piperacillin/tazobactam and cefepime in critically ill patients]

Author(s): Diego del Rio E, Soy Muner D, Gratacos Santanach L, Ribas Sala J

Affiliation(s): Servicio de Farmacia, Hospital Clinic, Barcelona, Espana. ediegode@gmail.com

Publication date & source: 2008-07, Farm Hosp., 32(4):199-207.

Publication type: English Abstract

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. METHOD: 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.