A nurse is caring for a client who is postoperative and develops respiratory depression after receiving morphine for pain control. Which of the following medications should the nurse expect the provider to prescribe?

A. Naloxone is a specific opioid antagonist that binds to opioid receptors in the central nervous system, displacing opioid molecules such as morphine. By doing so, it rapidly reverses the effects of opioids, including respiratory depression, sedation, and hypotension. Respiratory depression is the most serious adverse effect of morphine and other opioids, as it can lead to hypoxia, cardiac arrest, or death if not promptly treated. Naloxone has a fast onset of action, usually within 2–5 minutes when given intravenously, and can be repeated or administered as a continuous infusion if the opioid has a longer duration than naloxone. B. Diphenhydramine is an H1 receptor antagonist used to treat allergic reactions, motion sickness, and as a sedative. It does not reverse opioid-induced respiratory depression and can actually exacerbate sedation and CNS depression if administered in this context. Therefore, it is not appropriate for opioid overdose management. C. Flumazenil is a benzodiazepine antagonist used to reverse the sedative effects of benzodiazepines such as lorazepam or midazolam. While it can reverse CNS depression caused by benzodiazepines, it does not affect opioid receptors and will not improve respiratory depression caused by morphine. D. Calcium gluconate is used to treat conditions such as hypocalcemia, hyperkalemia with cardiac conduction changes, or calcium channel blocker overdose. It has no effect on opioid-induced respiratory depression and is not indicated in this scenario.