Naltrexone is

Naltrexone is

• A. A narcotic with local anesthetic properties
• B. An opioid antagonist used for treatment of previously detoxified heroin addicts
• C. A pure opioid antagonist with a shorter duration of action than naloxone
• D. A synthetic opioid derived from oxymorphone

Answer: (B)

Naltrexone is an opioid receptor antagonist used to help prevent relapse in people who have already completed detoxification from opioids, such as heroin. It blocks mu receptors so that if opioids are used, they no longer produce euphoria or pleasant effects, making relapse less likely. Because it is long-acting, it can be given in oral form or via longer-acting formulations to maintain blockade over days. It must be started after detoxification because, if a person who is still opioid-dependent takes it, naltrexone will precipitate withdrawal by abruptly blocking the opioids already in their system. It is not a narcotic with local anesthetic properties, nor is it a short-acting antagonist like naloxone. It is a pure antagonist, not an opioid agonist, and while it is related to oxymorphone in structure, its clinical role is as an antagonist, not as a synthetic opioid agonist.

Naltrexone is an opioid receptor antagonist used to help prevent relapse in people who have already completed detoxification from opioids, such as heroin. It blocks mu receptors so that if opioids are used, they no longer produce euphoria or pleasant effects, making relapse less likely. Because it is long-acting, it can be given in oral form or via longer-acting formulations to maintain blockade over days. It must be started after detoxification because, if a person who is still opioid-dependent takes it, naltrexone will precipitate withdrawal by abruptly blocking the opioids already in their system. It is not a narcotic with local anesthetic properties, nor is it a short-acting antagonist like naloxone. It is a pure antagonist, not an opioid agonist, and while it is related to oxymorphone in structure, its clinical role is as an antagonist, not as a synthetic opioid agonist.