Which statement by a patient on dialysis, taking gentamicin, should cause the nurse the most concern.

Choice A rationale Increased thirst or polydipsia can be related to many factors, including the dialysis process itself, fluid restriction challenges, or underlying hyperglycemia. While maintaining fluid balance is critical in dialysis patients, thirst is a common complaint and does not represent a life-altering toxicity specifically linked to gentamicin. It requires monitoring and patient education regarding fluid limits but is not as acutely concerning as irreversible sensory loss caused by medication side effects. Choice B rationale Headaches are a frequent occurrence in patients undergoing dialysis, often resulting from rapid shifts in fluids and electrolytes, changes in blood pressure, or caffeine withdrawal. While a severe headache warrants assessment to rule out hypertensive crisis or disequilibrium syndrome, it is not a classic sign of gentamicin toxicity. The nurse must evaluate the headache, but it does not specifically indicate the permanent organ damage associated with the administration of aminoglycoside antibiotics. Choice C rationale Diarrhea can occur in dialysis patients due to dietary changes, medication side effects, or localized infections. While two episodes of diarrhea require assessment for hydration status and potential Clostridioides difficile infection, it is generally a manageable symptom. It does not carry the same long-term morbidity as the permanent cranial nerve damage often seen with aminoglycoside use. The nurse should document the stool frequency but prioritize assessment of more severe toxicities. Choice D rationale Gentamicin is an aminoglycoside antibiotic known for its significant ototoxicity and nephrotoxicity. In a dialysis patient, renal clearance is already compromised, increasing the risk of toxic drug accumulation. A report of hearing loss or tinnitus suggests damage to the eighth cranial nerve, which is often irreversible. Because aminoglycosides can destroy sensory hair cells in the inner ear, the nurse must report this immediately to prevent further permanent hearing loss or vestibular dysfunction.