Which drug is NOT listed as an option for CRI without analgesia?

• A. Midazolam
• B. Propofol
• C. Alfaxalone
• D. Ketamine

Answer: (D)

The key idea is that a CRI without analgesia uses drugs that do not provide meaningful pain relief on their own, focusing on sedation or hypnosis instead. Midazolam (a benzodiazepine) and both propofol and alfaxalone are chosen for maintenance of anesthesia or deep sedation because they mainly produce sedation and unconsciousness without delivering significant analgesia at the typical infusion doses. Ketamine is different: it is a dissociative anesthetic with strong analgesic properties due to NMDA receptor antagonism. Because of its analgesic effect, ketamine is generally not used in a CRI labeled as “without analgesia.” It’s commonly included in analgesia-containing protocols or used when some analgesia is intended. So ketamine would not be listed for a CRI without analgesia, making it the best answer.