A nurse is caring for a client who is postoperative and receiving fentanyl via patient-controlled analgesia. The client has a prescription for naloxone. The nurse understands that the purpose of naloxone is which of the following?

Choice A rationale Naloxone, an opioid antagonist, is not indicated for treating urinary retention, which can be a side effect of opioid agonists like fentanyl due to increased tone of the detrusor muscle and sphincter. While discontinuing the opioid may resolve retention, naloxone's primary action is to reverse acute opioid-induced central nervous system and respiratory depression by competitive antagonism at opioid receptors, not to manage genitourinary dysfunction. Choice B rationale Nausea and vomiting are common side effects of opioid analgesics, mediated by stimulation of the chemoreceptor trigger zone in the medulla. While reversing the opioid effects with naloxone will subsequently reduce this symptom, naloxone is generally reserved for life-threatening opioid toxicity. Antiemetics like ondansetron or prochlorperazine are the standard pharmacological treatment for opioid-induced nausea. Choice C rationale Naloxone is a potent, rapid-acting opioid antagonist that competitively binds to and blocks opioid receptors, particularly μ (mu) receptors, in the central nervous system. This action effectively reverses the agonistic effects of opioids, such as respiratory depression, sedation, and analgesia, making it the essential treatment for acute opioid overdose. Choice D rationale Opioids can cause dryness of respiratory secretions due to their anticholinergic-like effects, not increased secretion. Naloxone's mechanism of action does not involve suppressing secretions; it specifically reverses the central nervous system depression caused by opioid agonists by competitively binding to opioid receptors. Standard treatments for excessive respiratory secretions involve suctioning or anticholinergic agents like atropine.