Final answer:
Naloxone is the drug that should be administered to reverse an opioid overdose, such as from an increased dose of IV morphine, restoring the patient's breathing and consciousness.
Step-by-step explanation:
The nurse should anticipate the administration of naloxone following the patient's unresponsive state due to a potential morphine overdose. Morphine is an opioid that can induce analgesia and, in higher doses, cause drowsiness and loss of consciousness. When a patient exhibits signs of opioid overdose, such as a significantly decreased respiratory rate, naloxone is used as an opioid antagonist to reverse the effects of the opioid, particularly respiratory depression. It is critical in emergency situations to restore the patient's normal breathing pattern.