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Updated: Feb 27, 2026
Physiology Lab Demonstration: Glomerular Filtration Rate in a Rat
Published on: July 26, 2015
Does Secretory Clearance Follow Glomerular Filtration Rate in Chronic Kidney Diseases? Reconsidering the Intact
A Chapron1, D D Shen1,2, B R Kestenbaum3
1Department of Pharmaceutics, School of Pharmacy, University of Washington, Seattle, Washington, USA.
Abstract:
Drug-dose modification in chronic kidney disease (CKD) utilizes glomerular filtration rate (GFR) with the implicit assumption that multiple renal excretory processes decline in parallel as CKD progresses. We compiled published pharmacokinetic data to evaluate if GFR predicts renal clearance changes as a function of CKD severity. For each drug, we calculated ratio of renal clearance to filtration clearance (Rnf). Of 21 drugs with Rnf >0.74 in subjects with GFR >90 mL/min (implying filtration and secretion), 13 displayed significant change in Rnf vs. GFR (slope of linear regression statistically different from zero), which indicates failure of GFR to predict changes in secretory clearance. The dependence was positive (n = 3; group A) or negative (n = 10; group B). Eight drugs showed no correlation (group C). Investigated drugs were small molecules, mostly hydrophilic, and ionizable, with some characterized as renal transporter substrates. In conclusion, dosing adjustments in CKD require refinement; in addition to GFR, biomarkers of tubular function are needed for secreted drugs.
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