For moderate to severe pain, which analgesic type is recommended?

• A. Partial agonist like buprenorphine
• B. Full opioid agonist like morphine, hydromorphone, or methadone
• C. Antagonist like naloxone
• D. Mixed agonist-antagonist like pentazocine

Answer: (B)

Full opioid agonists provide the strongest, most reliable analgesia for moderate to severe pain by fully activating mu-opioid receptors, which yields powerful pain relief that can be titrated to the response. This makes them the preferred option when pain is intense and requires adjustable dosing to match the patient’s needs.

Buprenorphine is a partial agonist with high receptor affinity and a ceiling effect, so it often isn’t sufficient for severe pain and can complicate the use of additional opioids if pain escalates. Naloxone is an opioid antagonist and does not provide analgesia; it’s used to reverse effects of opioids, not to treat pain. Pentazocine is a mixed agonist-antagonist with less robust analgesia and potential adverse effects, and it can interfere with full-opioid–based pain control.

Thus, for moderate to severe pain, a full opioid agonist such as morphine, hydromorphone, or methadone is the best choice.