Nalmefene has which primary advantage over naloxone?

Nalmefene has which primary advantage over naloxone?

• A. Higher risk of withdrawal
• B. Longer duration of action than naloxone
• C. More rapid metabolism
• D. No reversal of opioid effects

Answer: (B)

The main concept here is how long the antagonist blocks opioid receptors. Naloxone works quickly but is short-acting, so its effects wear off and opioid toxicity can recur unless you dose again or give an infusion. Nalmefene, on the other hand, has a longer duration of action due to slower metabolism and a longer half-life. This means it maintains receptor blockade longer, providing a more sustained reversal of opioid effects and reducing the need for repeated dosing. The other statements don’t fit: nalmefene does reverse opioid effects, it isn’t known for more rapid metabolism (it’s the opposite), and while withdrawal can occur with opioid antagonists in dependent individuals, the notable practical advantage of nalmefene is its longer duration, not a higher withdrawal risk.

The main concept here is how long the antagonist blocks opioid receptors. Naloxone works quickly but is short-acting, so its effects wear off and opioid toxicity can recur unless you dose again or give an infusion. Nalmefene, on the other hand, has a longer duration of action due to slower metabolism and a longer half-life. This means it maintains receptor blockade longer, providing a more sustained reversal of opioid effects and reducing the need for repeated dosing.

The other statements don’t fit: nalmefene does reverse opioid effects, it isn’t known for more rapid metabolism (it’s the opposite), and while withdrawal can occur with opioid antagonists in dependent individuals, the notable practical advantage of nalmefene is its longer duration, not a higher withdrawal risk.