The nurse notes a medication ordered for a client is advised to use with caution in the elderly due to declining renal function. Which of the following nursing interventions is an example of a precaution?

A. Administering medications at different times: timing does not affect renal function monitoring. B. Comparing the client’s armband with the MAR: this is a safety check, not a precaution for renal function. C. Monitoring for a decrease in BUN and creatinine: a decrease does not indicate renal impairment. D. Closely monitoring the client's BUN and creatinine for an increase from baseline: Renal function declines with age, increasing the risk of drug accumulation and toxicity. An increase in BUN (normal: 7-20 mg/dL) and creatinine (normal: 0.6-1.3 mg/dL) indicates worsening kidney function and necessitates medication adjustments.