Which statement about tramadol's reversal with naloxone is true?

Which statement about tramadol's reversal with naloxone is true?

• A. Naloxone completely reverses analgesia
• B. Naloxone reverses analgesia fully and sedation
• C. Naloxone reverses respiratory depression and sedation but not all analgesia
• D. Naloxone has no effect on tramadol

Answer: (C)

Naloxone blocks the mu-opioid receptor component of tramadol’s action, so it will reverse the opioid effects such as respiratory depression and sedation. But tramadol also produces analgesia through non-opioid means—namely its inhibition of serotonin and norepinephrine reuptake—which naloxone does not affect. Because part of tramadol’s analgesia comes from these monoaminergic mechanisms, analgesia is not completely abolished by naloxone. Thus, respiratory depression and sedation are reversed, but analgesia persists to some extent.

Naloxone blocks the mu-opioid receptor component of tramadol’s action, so it will reverse the opioid effects such as respiratory depression and sedation. But tramadol also produces analgesia through non-opioid means—namely its inhibition of serotonin and norepinephrine reuptake—which naloxone does not affect. Because part of tramadol’s analgesia comes from these monoaminergic mechanisms, analgesia is not completely abolished by naloxone. Thus, respiratory depression and sedation are reversed, but analgesia persists to some extent.