Partial antagonists can be used in anesthesia in combination with which of the following agents?

Partial antagonists can be used in anesthesia in combination with which of the following agents?

• A. Propofol and fentanyl
• B. Ketamine and propofol
• C. Nitrous oxide and benzodiazepines
• D. Sevoflurane and nitrous oxide

Answer: (C)

Partial antagonists are opioids that provide analgesia with less risk of deep respiratory depression because they only partially activate mu receptors (or block mu enough to blunt full mu effects). In anesthesia this ceiling on respiratory depression is especially valuable when you’re adding other CNS depressants. Pairing a partial antagonist with agents like nitrous oxide (a mild inhaled sedative/analgesic) and benzodiazepines (potent sedatives) gives balanced anesthesia: you get analgesia and anxiolysis without piling on respiratory compromise from a full mu agonist. Drugs such as nalbuphine or butorphanol illustrate this approach, offering meaningful analgesia while keeping the respiratory effects more controllable than with a pure mu agonist. The other combinations rely on either full mu agonists or drugs that don’t leverage the ceiling effect of a partial antagonist. Propofol with fentanyl, for example, risks greater respiratory depression; ketamine–propofol uses different mechanisms for sedation and analgesia; and sevoflurane with nitrous oxide emphasizes inhaled anesthesia without the specific partial mu-receptor moderation that characterizes partial antagonists.

Partial antagonists are opioids that provide analgesia with less risk of deep respiratory depression because they only partially activate mu receptors (or block mu enough to blunt full mu effects). In anesthesia this ceiling on respiratory depression is especially valuable when you’re adding other CNS depressants. Pairing a partial antagonist with agents like nitrous oxide (a mild inhaled sedative/analgesic) and benzodiazepines (potent sedatives) gives balanced anesthesia: you get analgesia and anxiolysis without piling on respiratory compromise from a full mu agonist. Drugs such as nalbuphine or butorphanol illustrate this approach, offering meaningful analgesia while keeping the respiratory effects more controllable than with a pure mu agonist.

The other combinations rely on either full mu agonists or drugs that don’t leverage the ceiling effect of a partial antagonist. Propofol with fentanyl, for example, risks greater respiratory depression; ketamine–propofol uses different mechanisms for sedation and analgesia; and sevoflurane with nitrous oxide emphasizes inhaled anesthesia without the specific partial mu-receptor moderation that characterizes partial antagonists.