Pharmacology · single question
An elderly patient (90 years old) needs antibiotic therapy. What is the MOST important pharmacologic consideration related to their age?
Show answer and explanation
Correct answer: D. Decreased glomerular filtration rate (GFR)
In elderly patients, decreased GFR (glomerular filtration rate) is the most clinically significant pharmacologic concern. Renal function declines with age — GFR decreases approximately 1 mL/min/year after age 40. Many antibiotics (e.g., penicillins, cephalosporins, fluoroquinolones) are renally cleared, so reduced GFR leads to drug accumulation, toxicity, and prolonged effects. Dose adjustment or extended dosing intervals are required.
- A. ❌ Drug absorption is not significantly increased with age; it may actually slow down.
- B. ❌ Plasma protein binding typically decreases in elderly patients (less albumin), but this has less impact on antibiotic dosing than renal function.
- C. ❌ Hepatic first-pass metabolism actually decreases in elderly patients, but renal clearance is the more critical concern for antibiotics.
- D. ✅ CORRECT – Decreased GFR is the primary age-related pharmacologic concern; many antibiotics accumulate in elderly patients with reduced renal function.