Which finding indicates that a client receiving gentamicin is developing toxicity?

Gentamicin is an aminoglycoside antibiotic that, while effective in treating certain bacterial infections, has a risk for toxicity, particularly to the kidneys and the auditory system. Tinnitus, or ringing in the ears, is a well-documented side effect and a critical sign that can indicate ototoxicity associated with gentamicin use. The auditory toxicity is due to the drug damaging the cochlea and auditory nerve, leading to hearing problems. Patients or healthcare providers should monitor for the onset of tinnitus as it may signal the need to adjust the medication or monitor medication levels more closely to prevent further complications.

Other findings, while important in clinical assessments, are not specific indicators of gentamicin toxicity. For instance, monitoring the trough level of the medication is essential to ensure that it remains within the therapeutic range, but it does not directly indicate toxicity unless it is excessively high. Weight loss could occur for various reasons unrelated to drug toxicity, and reduced kidney function is a concern but often follows a different path regarding gentamicin toxicity than auditory symptoms. Therefore, tinnitus stands out as a specific and direct indicator of potential toxicity in clients receiving this medication.