Creatinine clearance following cimetidine for estimation of glomerular filtration rate
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Original article
Creatinine clearance following cimetidine for estimation of glomerular filtration rate Stanley Hellerstein, Max Berenbom, Uri S. Alon, and Bradley A. Warady Section of Nephrology, The Children's Mercy Hospital and The University of Missouri, School of Medicine at Kansas City, Missouri, USA Received January 21, 1997; received in revised form June 16, 1997; accepted June 20, 1997
Abstract. Simultaneous inulin (Cin) and creatinine clearance (CCr) studies were performed on 53 pediatric renal patients using a cimetidine protocol. Since cimetidine blocks the tubular secretion of creatinine, it was hypothesized that CCr measured following cimetidine would closely approximate the Cin. Cin was compared with CCr with the latter calculated from: (1) a 24-h urine collection, (2) plasma creatinine, height, and a proportionality constant, (3) the same plasma and urine specimens used for calculating Cin, and (4) from the plasma and urine specimens of the four 30-min clearance periods treated as a single 2-h clearance. The Cin was very closely approximated by the CCr calculated from the same specimens used for the Cin and by the 2-h clearance. The cimetidine protocol, with CCr derived from a 2-h urine collection obtained under supervision in the office or clinic, provides a convenient and inexpensive procedure for estimation of glomerular filtration rate in a clinical setting.
numerous studies have documented the inaccuracy of these estimates [1 ± 8]. The failure of CCr to closely approximate inulin clearance (Cin), the gold standard for GFR, is primarily a result of the tubular secretion of Cr. The disparity between Cin and CCr increases as GFR decreases. A number of reports in adult patients and our studies in children have shown that CCr closely approximates GFR when the tubular secretion of Cr is inhibited by cimetidine [2, 9 ± 19]. A variety of protocols have been employed in which cimetidine has been administered either as a single dose or over 1 to several days to inhibit the tubular secretion of Cr. The present report describes the results of the use of a cimetidine protocol for estimation of GFR in clinically stable pediatric renal patients. A relatively convenient and inexpensive procedure is described in which a 2-h CCr in patients pre-treated with cimetidine is shown to closely approximate Cin.
Key words: Inulin clearance ± Creatinine clearance ± Cimetidine ± Glomerular filtration rate
Patients and methods
Introduction The level of glomerular filtration rate (GFR) is followed closely in seriously ill patients because of the importance of renal function in fluid balance and in the excretion of antibiotics and chemotherapeutic agents. In addition, GFR is the accepted parameter for monitoring renal function in urinary tract and kidney disorders, and for evaluating the effect of interventions. In clinical practice GFR is usually monitored using serum or plasma creatinine concentrations ([Cr]s or [Cr]p) or creatinine clearance (CCr), although Correspondence to: S. Hellerstein, The Children's Mercy Hospi
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