Pharmacology · patient case question
When prescribing an antibiotic for this 90-year-old patient, which physiologic change is most important to consider?
Patient case: The Geriatric Patient
demo: 90-year-old female
chief: “My mouth is always dry and this tooth is throbbing.”
history: Osteoporosis, mild renal impairment, hypertension. Ambulates with a walker.
meds: Alendronate, methotrexate, zoledronate infusions in the past, hydrochlorothiazide
findings: Generalized xerostomia. Tooth #30 with a periapical abscess requiring antibiotic coverage. Panoramic radiograph shows thinned mandibular cortices.
Show answer and explanation
Correct answer: C. Decreased glomerular filtration rate from age-related renal decline
- A. Hepatic metabolism decreases with age rather than increases, and hepatic blood flow declines.
- B. Gastric acid production typically decreases with age, which can alter absorption of pH-dependent drugs.
- C. Correct. GFR falls progressively with age, so renally cleared drugs accumulate. Dose reduction or interval extension is often required in the very elderly.
- D. Serum albumin tends to fall in the elderly, increasing the free fraction of highly protein-bound drugs.