In a 70-year-old patient prescribed acyclovir, which function should the nurse prioritize assessing?

In the context of a 70-year-old patient prescribed acyclovir, prioritizing the assessment of renal function is crucial due to the drug's pharmacokinetics and potential side effects. Acyclovir is primarily excreted through the kidneys, and in older adults, there may be a decline in renal function that can increase the risk of toxicity. Monitoring renal function, including serum creatinine and blood urea nitrogen (BUN) levels, ensures that the medication is being excreted properly and helps prevent complications such as renal impairment or neurological toxicity, which can occur if the drug accumulates in the body.

Neurologic function is important when using acyclovir, especially if there are symptoms of toxicity, but it is contingent upon renal function being adequately assessed first. While cardiac and respiratory functions are generally important in nursing assessments, they are not as directly related to the administration of acyclovir as renal function is, making renal health the priority in this scenario.