Which medication is an example of a PAMORA and what is its clinical indication?

• A. Naloxone for opioid overdose.
• B. Naloxegol for opioid-induced constipation in non-cancer patients.
• C. Methadone for pain.
• D. Loperamide for diarrhea relief.

Answer: (B)

PAMORAs are drugs that block mu-opioid receptors in the gut without reversing pain relief, because they act mainly outside the central nervous system. Naloxegol fits this, as it’s a PAMORA designed to stay in the periphery and limit central penetration. It’s used to treat opioid-induced constipation in adults with chronic non-cancer pain, addressing the gut effects of opioids without diminishing analgesia.

Naloxone would reverse opioid effects centrally and peripherally and is not a peripherally restricted antagonist. Methadone is an opioid agonist used for pain, not an antagonist. Loperamide is an opioid receptor agonist used to treat diarrhea, not an antagonist, so it doesn’t fit the PAMORA category.