How Kidney Function Changes With Age | Older Adults (Special Populations 13.2)

How does age change the clearance of a drug that the kidneys excrete? Lesson 13.2 of our special populations module covers five parts: the decrease in kidney function, its estimation, the liver, polypharmacy, and the guideline ICH E7. The worked example is gabapentin, with a published single-dose study in 36 healthy subjects aged 20 to 78 years and the US label. 0:00 Older adults, GFR and clearance 1:13 Decrease in kidney function 2:14 Estimation of kidney function 3:07 Liver 3:29 Polypharmacy 3:58 ICH E7 4:35 Gabapentin study 5:42 Gabapentin label 6:29 Summary Sources International Council for Harmonisation. E7 Studies in support of special populations: geriatrics. ICH guideline. 1993. https://www.govinfo.gov/content/pkg/F... van Marum RJ. Underrepresentation of the elderly in clinical trials, time for action. Br J Clin Pharmacol. 2020. PMID 32909294 Masnoon N, Shakib S, Kalisch-Ellett L, et al. What is polypharmacy? A systematic review of definitions. BMC Geriatr. 2017. PMID 29017448 Rowe JW, Andres R, Tobin JD, et al. The effect of age on creatinine clearance in men: a cross-sectional and longitudinal study. J Gerontol. 1976. PMID 1249404 Lindeman RD, Tobin J, Shock NW. Longitudinal studies on the rate of decline in renal function with age. J Am Geriatr Soc. 1985. PMID 3989190 Cockcroft DW, Gault MH. Prediction of creatinine clearance from serum creatinine. Nephron. 1976. PMID 1244564 Inker LA, Eneanya ND, Coresh J, et al. New creatinine- and cystatin C-based equations to estimate GFR without race. N Engl J Med. 2021. PMID 34554658 Baxmann AC, Ahmed MS, Marques NC, et al. Influence of muscle mass and physical activity on serum and urinary creatinine and serum cystatin C. Clin J Am Soc Nephrol. 2008. PMID 18235143 Janssen I, Heymsfield SB, Wang ZM, et al. Skeletal muscle mass and distribution in 468 men and women aged 18-88 yr. J Appl Physiol. 2000. PMID 10904038 Schaeffner ES, Ebert N, Delanaye P, et al. Two novel equations to estimate kidney function in persons aged 70 years or older. Ann Intern Med. 2012. PMID 23027318 Martus P, Ebert N, van der Giet M, et al. An efficient approach for glomerular filtration rate assessment in older adults. Br J Clin Pharmacol. 2014. PMID 24472092 Wynne HA, Cope LH, Mutch E, et al. The effect of age upon liver volume and apparent liver blood flow in healthy man. Hepatology. 1989. PMID 2643548 Klotz U. Pharmacokinetics and drug metabolism in the elderly. Drug Metab Rev. 2009. PMID 19514965 Johnell K, Klarin I. The relationship between number of drugs and potential drug-drug interactions in the elderly: a study of over 600,000 elderly patients from the Swedish Prescribed Drug Register. Drug Saf. 2007. PMID 17867728 Boyd RA, Türck D, Abel RB, et al. Effects of age and gender on single-dose pharmacokinetics of gabapentin. Epilepsia. 1999. PMID 10219274 Viatris Specialty LLC. Neurontin (gabapentin) capsules, tablets and oral solution: DailyMed label. 2025. https://dailymed.nlm.nih.gov/dailymed... Illustrations adapted from Servier Medical Art (smart.servier.com), CC BY 4.0. Structures drawn with RDKit.