A patient in pain requests the prescribed pain medication, which is an opioid. Which nursing assessment is essential before administering the opioid?

The correct answer is D: Respiratory. Before administering an opioid, it is essential to assess the patient's respiratory status due to the potential side effect of respiratory depression. Monitoring the respiratory rate, depth, and effort can help detect any signs of respiratory distress. Blood pressure, temperature, and pulse are important assessments but not as crucial as respiratory status when administering opioids. Respiratory assessment takes priority due to the life-threatening risk of respiratory depression associated with opioid use.