Which pain medication may be administered to the patient as needed?

Choice A reason: Fentanyl patches provide continuous opioid delivery for 72 hours; their fixed schedule isn’t “as needed,” making them unsuitable for acute, variable pain management. Choice B reason: Acetaminophen with oxycodone is scheduled every 6 hours; this fixed interval lacks the flexibility of “as needed,” limiting its use for breakthrough pain relief. Choice C reason: Morphine extended-release is designed for sustained release over 12 hours; its fixed dosing isn’t “as needed,” restricting its role to chronic, not acute, pain control. Choice D reason: Ketorolac IV every 4 hours prn allows flexible dosing; this NSAID targets inflammation and pain acutely, ideal for as-needed administration within safe limits.