A client who is obtunded arrives in the emergency department with a suspected drug overdose. The client becomes responsive after the administration of IV naloxone, but within a short period, the client's level of consciousness decreases again and the respiratory rate decreases to 6 breaths/minute. Which action should the nurse take first?

A. Administer an additional dose of naloxone: Naloxone has a shorter half-life than many opioids, leading to the recurrence of respiratory depression once its effects wear off. When signs of opioid toxicity return, the immediate priority is to administer another dose of naloxone to reverse life-threatening respiratory depression and restore adequate ventilation. B. Initiate a second intravenous access site: While maintaining IV access is important in emergency care, establishing a second IV line is not the most urgent priority when the client’s breathing is dangerously slow. Immediate reversal of respiratory depression takes precedence. C. Prepare to initiate cardiopulmonary resuscitation (CPR): CPR is indicated if the client has no pulse or is not breathing. Since the client is still breathing, although minimally, and has a pulse, the immediate action should be reversing the opioid effects with naloxone, not starting CPR. D. Determine if results of the drug toxicity screen are available: While knowing the substances involved can guide further treatment, waiting for lab results would delay the critical intervention needed to treat the acute respiratory depression at this moment.