The nurse is caring for a patient who is receiving an intravenous antibiotic. The patient has a serum drug trough of 1.5 mcg/mL. The normal trough for this drug is 1.7 to 2.2 mcg/mL. What will the nurse expect the patient to experience?

A. inadequate therapeutic effects: A trough level below the therapeutic range indicates insufficient drug concentration in the blood. This may result in the antibiotic being less effective at eliminating the infection, potentially delaying recovery. B. Excessive adverse effects: Low trough levels reduce the risk of adverse effects rather than causing them. Toxicity and side effects are more likely with elevated drug levels, not subtherapeutic levels. C. Signs of drug toxicity: Toxicity occurs when drug levels exceed the upper therapeutic limit, not when they are below range. A trough of 1.5 mcg/mL is subtherapeutic, so toxicity is unlikely. D. Increased risk for superinfection: While prolonged ineffective therapy may increase infection complications over time, the immediate concern with a low trough is inadequate antimicrobial activity rather than direct development of superinfections.