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Comparative Evaluation of the Cockcroft‐Gault Equation and the Modification of Diet in Renal Disease (MDRD) Study Equation for Drug Dosing: An Opinion of the Nephrology Practice and Research Network of the American College of Clinical Pharmacy
Author(s) -
Nyman Heather A.,
Dowling Thomas C.,
Hudson Joanna Q.,
Peter Wendy L. St.,
Joy Melanie S.,
Nolin Thomas D.
Publication year - 2011
Publication title -
pharmacotherapy: the journal of human pharmacology and drug therapy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.227
H-Index - 109
eISSN - 1875-9114
pISSN - 0277-0008
DOI - 10.1592/phco.31.11.1130
Subject(s) - dosing , medicine , renal function , creatinine , pharmacokinetics , drug , dose , intensive care medicine , nephrology , pharmacology
Accurate assessment of kidney function is an important component of determining appropriate drug dosing regimens. Nearly all manufacturer‐recommended dosage adjustments are based on creatinine clearance ranges derived from clinical pharmacokinetic studies performed during the drug development process. The Cockcroft‐Gault (CG) equation provides an estimate of creatinine clearance and is the equation most commonly used to determine drug dosages in patients with impaired kidney function. The Modification of Diet in Renal Disease (MDRD) study equation has also been proposed for this purpose. Published studies report that drug dosages determined by the two equations do not agree in 1 0–40% of cases. However, interpretation and comparison of these studies are complicated by the variable creatinine methods used for calculating CG and MDRD estimates, the patient populations studied, and a lack of outcomes data demonstrating the clinical significance of dosing discrepancies. Moreover, the impact of reporting standardized serum creatinine values on the accuracy of the CG equation and corresponding drug dosing regimens have been questioned. Currently, no prospective pharmacokinetic studies have been conducted with use of the MDRD equation to generate dosing recommendations, and limited data are available to support its use in some patient populations representing demographic extremes. Collectively, these issues have resulted in considerable confusion among clinicians and have fueled a healthy debate on whether or not to use the MDRD equation to determine drug dosages. Each of these issues is reviewed, and a proposed algorithm for using creatinine‐based kidney function assessments in drug dosing is provided. Knowledge of the advantages, limitations, and clinical role of each equation will facilitate their safe and effective use in drug dosing.