A nurse is reviewing the medication record for a client who has chronic kidney disease. Which of the following medications should the nurse identify as having the potential to cause nephrotoxicity?

Rationale: A. Vancomycin, an aminoglycoside-like antibiotic, is nephrotoxic, especially when administered in high doses or for prolonged periods. It can cause acute tubular necrosis and should be used with caution in clients with chronic kidney disease (CKD). Serum trough levels must be carefully monitored to maintain therapeutic effect while preventing toxicity. B. Omeprazole is a proton pump inhibitor (PPI) used for gastric acid suppression. While long-term use has been associated with a small risk of interstitial nephritis, it is not a common direct nephrotoxin and is generally considered safe for most CKD clients. C. Diphenhydramine (Benadryl) is an antihistamine that may cause urinary retention or sedation, but it does not cause nephrotoxicity. D. Ondansetron (Zofran) is an antiemetic that acts on serotonin receptors and has no nephrotoxic effects.