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Error dependent on renal function when monoexponential equation assumed
Author(s) -
MacKichan Janis J.,
, Michael R. Dobrinsk,
Welling Peter G.,
Wagner John G.
Publication year - 1977
Publication title -
clinical pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.941
H-Index - 188
eISSN - 1532-6535
pISSN - 0009-9236
DOI - 10.1002/cpt1977225part1609
Subject(s) - volume of distribution , renal function , metabolic clearance rate , distribution volume , distribution (mathematics) , clearance , plasma clearance , pharmacokinetics , function (biology) , chemistry , mathematics , urology , medicine , mathematical analysis , biology , evolutionary biology
An example from the literature has been used to demonstrate errors involved in calculating drug clearance by inappropriate use of the apparent drug distribution volume V dext . The V dext is always an overestimate of the true volume of distribution in a multicompartment system, and the degree of overestimation in using it to calculate clearance for such a system will increase as renal function increases. Drug dosages calculated on the basis of overestimated clearance values may give rise to overdosage in normal individuals, or therapeutic failure in severely uremic patients. Problems associated with the use of an oversimplified pharmacokinetic model for clearance calculations are discussed, together with the concept of model‐independent calculations.