Drug Dosage Adjustment Using Renal Estimation Equations: A Review of the Literature

Purpose To examine the factors affecting drug clearance and the available evidence for drug dosing based on the Cockcroft-Gault (CG) equation and the abbreviated Modification of Diet in Renal Disease (abbrMDRD) equation. Factors that would distort the accuracy of these formulas and the affect of this distortion on the use of either formula in drug dosage adjustment were reviewed. Methods An updated review of the literature was performed that pertained to the accuracy of the CG and abbrMDRD equations and their use in drug dosage adjustment. MEDLINE was searched using the OVIDSP database, from the inception of the database (1950) through June 2008. Discussion To cover the major issues concerning the use of renal estimation equations in drug dosing adjustment, various areas were examined. Topics included the accuracy of the CG and abbrMDRD formulas, variability in these equations because of patient and laboratory factors, the isotope dilution-mass spectrometry standardization initiative, and the applicability of each formula to modifying medication doses. Conclusion Although the abbrMDRD equation has many advantages as compared with the CG equation, too little research has been completed at this time to recommend the clinical use of the abbrMDRD equation in pharmacy practice.