Opioid antagonists that produce less severe withdrawal are:

• A. Maintenance agonists
• B. Pseudo-antagonists
• C. Partial antagonists
• D. Opioid agonists

Answer: (C)

The idea here is that any drug’s effect on withdrawal depends on how fully it activates opioid receptors. A drug with partial activity at mu receptors can occupy the receptors and provide some stimulation, but not as much as a full opioid. In someone who is opioid-dependent, that partial activation blunts withdrawal symptoms compared with a drug that completely blocks receptors. So a substance with partial antagonist/partial agonist properties will produce milder withdrawal than a pure antagonist would, while still helping manage dependence by occupying receptors and reducing cravings. An example is a partial agonist like buprenorphine, which has high receptor affinity, a ceiling effect, and a milder withdrawal profile. In contrast, maintenance agonists would keep opioid effects going, and full opioid agonists would not reduce withdrawal, while a pure antagonist would precipitate strong withdrawal.