Authors: Edmund H. Duthie, MD, Christopher J. Anderson, Brahm Vasudev, Bambi Wessel
Objectives:
ACGME Competencies: Medical Knowledge, Patient Care, Systems-based Practice
Context: Patient in a hospital or other healthcare facility
Action: Elderly patient requires pharmacotherapy
Incidence/Prevalence:According to the CDC, just over 40% of the US population over 65 has chronic kidney disease[i].
Underlying Science: Genetic factors, replicative senescence and oxidative stress are all felt to "age" the kidney so that there is arterial sclerosis with hypoxic and ischemic injury that lead to glomerular sclerosis, tubular atrophy, and interstitial fibrosis. The net effect is the decline in renal function (decrease in GFR, decreased diluting capacity and concentrating ability).
Est. Creatinine Clearance = [[140 - age(yr)] x weight(kg)]/[72 x serum Cr(mg/dL)] (multiply by 0.85 for women)
Assessment: Pharmacological Considerations
Considerations
Adverse Effects
Action
ACE-Inhibitors and
ARB’s
Interferes with autoregulation of renal blood flow
Hyperkalemia, decreased GFR
Check K+ and GFR one week after starting medication.
Antibiotics (Aminoglycosides, Vancomycin)
Chronic comorbidities such as CHF, HTN, and DM predispose to development of severe tubular injury.
Decreased GFR (elevated SCr), ATN, ototoxicity
Evaluate renal function prior to starting therapy (MDRD). Consider pharmacologic profiling. Avoid combinations with potentially nephrotoxic mediations.
NSAID
Decreased GFR, ATN, falls, GI bleeding
Consider alternative analgesic or adjuvant therapy (ice/heat packs), monitor renal function
Opiates
Morphine, meperidine, detroporoxyphene or their metabolites can accumulate.
Altered mental status, respiratory depression, hyponatremia (SIADH)
Consider regular doses of long acting +/- prn breakthrough doses.
Reassess every 3-5 days
Preferred opiates include hydromophoone and fentanyl.
Oral Hypoglycemics (Glyburide, extended release glipizide)
Long acting sulfonylureas
Hypoglycemia
Consider using shorter acting sulfonylurea (glimepiride)
Radiocontrast
Decreased GFR (elevated SCr), ATN
Evaluate renal function prior to use of contrast. Consider pre-procedure IV hydration , N-acetylcystine, Vitamin C, or iso-osmolar contrast.
References:
Author Affiliation: Medical College of Wisconsin, Milwaukee, Wisconsin.
Geriatric Fast Facts are edited by the faculty of the Geriatric Education Teams (GETS) program funded by the Reynolds Foundation, Kathryn Denson, MD, Steven Denson, MD, & Edmund Duthie, MD from the Division of Geriatrics, Medical College of Wisconsin, and are published by the Geriatric Fast Facts Website at the Medical College of Wisconsin. For more information write Kathryn Denson, MD. More information, as well as the complete set of Fast Facts, available at www.mcw.edu/Geriatric-Fast-Facts.htm
Copyright/Referencing Information: Users are free to download and distribute Geriatric Fast Facts for educational purposes only. Citation: Edmund H. Duthie, MD, Christopher J. Anderson, Brahm Vasudev, Bambi Wessel - Fast Fact #7: Pharmacologic aspects of renal drug clearance in the elderly patient . February 2012, 14, Geriatric Fast Facts, available at www.mcw.edu/Geriatric-Fast-Facts.htm
Disclaimer: Geriatric Fast Facts provide educational information. This information is not medical advice. Health care providers should exercise their own independent clinical judgment. Some Geriatric Fast Facts cite the use of a product in a dosage, for an indication, or in a manner other than that recommended in the product labeling. Accordingly, the official prescribing information should be consulted before any such product is used.