An 82-year-old man with heart failure receives IV gentamicin for enterococcal endocarditis. Which feature of his presentation places him at the greatest risk of cochlear toxicity?
- A Concurrent furosemide therapy and advanced age ✓
- B Once-daily dosing schedule
- C Co-administration with intravenous penicillin G
- D A diet rich in calcium-containing foods
Correct answer: A. Concurrent furosemide therapy and advanced age
Explanation
Ototoxicity from aminoglycosides is cumulative, irreversible, and increases with advanced age, preexisting renal impairment, higher total dose, prolonged therapy, and concurrent loop diuretics such as furosemide, which have additive cochlear toxicity. Once-daily dosing actually reduces toxicity because uptake into inner ear and renal cells saturates at high concentrations. Penicillin co-administration does not potentiate ototoxicity, though it can inactivate aminoglycosides if mixed in the same infusion line.
Reference: Katzung Basic and Clinical Pharmacology, 15th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.