A client is receiving intravenous vancomycin, and the nurse plans to draw blood for a peak and trough to determine the serum level of the drug. Which collection times would provide the best determination of these levels?

The correct answer is D. Immediately after completion of the IV dose and 30 minutes before the next administration of the medication. Explanation: Peak levels measure the highest concentration of the drug in the bloodstream, typically drawn immediately after completion of the infusion. Trough levels measure the lowest concentration, typically drawn 30 minutes before the next scheduled dose to ensure effective drug levels while preventing toxicity. Why the other options are incorrect: A. One hour after completion of the IV dose and one hour before the next administration – Waiting one hour for the peak level could lead to an inaccurate measurement, as the drug may already be metabolized or distributed. B. Two hours after completion of the IV dose and two hours before the next administration – This timing is too late for both peak and trough levels, missing the best points for measurement. C. Thirty minutes into the administration of the IV dose and 30 minutes before the next administration – The sample drawn mid-infusion does not represent peak levels, making this method ineffective. Key takeaway: Peak and trough monitoring for vancomycin is essential to maximize effectiveness while avoiding nephrotoxicity and ototoxicity. Proper timing ensures accurate therapeutic drug monitoring.