Drug dosing using estimated glomerular filtration rate: Misclassification due to metamizole interference in a creatinine assay

• Published in: Annals of clinical biochemistry 2021-09, Vol.58 (5), p.474-480
• Main Authors: Bojko, Luana, Ripka, Gustavo de Paula, Dionísio, Laura Mattana, Borges, Celso Luiz, Borato, Danielle Cristyane Kalva, Moss, Mariane de Faria
• Format: Article
• Language: English
• ISSN: 0004-5632; 1758-1001
• DOI: 10.1177/00045632211020029

Background The estimated glomerular filtration rate is a rather important measurement for patients under intensive care, since they often receive several drugs, and impaired renal function may result in misleading dosing. The estimated glomerular filtration is derived from mathematical models using serum creatinine, a measurement that suffers interference of some drugs, such as metamizole. This study intended to evaluate the impact on patient stratification for dose adjustment of two antimicrobials (meropenem and vancomycin) caused by metamizole interference in creatinine measurement by dry chemistry. Methods A cross-sectional study was conducted with a group of 108 hospitalized patients under metamizole prescriptions at fixed intervals. Serum creatinine concentrations were determined by enzymatic dry chemistry and Jaffé assays, and the estimated glomerular filtration rate was calculated through the CKD-EPI equation. Patients were stratified in groups according to their estimated glomerular filtration rate for drug dosing of vancomycin and meropenem. Results Creatinine values were significantly lower in measurements performed by the dry chemistry method in comparison to Jaffé assay (P