A nurse is collecting data from a client who has pyelonephritis and is receiving gentamicin via IV infusion. Which of the following manifestations should the nurse identify as an adverse effect of the treatment?

A. Hypotension: Gentamicin is an aminoglycoside antibiotic that primarily affects the kidneys and auditory system rather than blood pressure. Hypotension is not a common adverse effect of gentamicin; however, dehydration related to nephrotoxicity could contribute to blood pressure fluctuations. B. Hearing loss: Ototoxicity is a known adverse effect of gentamicin due to its accumulation in the inner ear, leading to damage of the cochlear and vestibular structures. Clients may report tinnitus, dizziness, or difficulty hearing, and prolonged exposure increases the risk of irreversible auditory impairment. C. Hyperthermia: Fever is typically a sign of infection rather than an adverse effect of gentamicin. While aminoglycosides can cause fever in rare cases due to a drug-induced reaction, hyperthermia is not a common side effect and should prompt evaluation for worsening infection or another underlying cause. D. Constipation: Gentamicin does not significantly affect gastrointestinal motility. While some antibiotics may cause gastrointestinal upset, nausea, or diarrhea, constipation is not a recognized adverse effect of gentamicin therapy.