Naltrexone

Summary

Naltrexone is a medication that works as an opioid antagonist. It is long-acting, with effects lasting 24 to 72 hours after a single dose. Clinically, naltrexone is used to reduce opioid cravings, which can help prevent relapse in those with opioid use disorder. It may also help with alcohol and smoking cessation. A notable side effect of naltrexone is weight loss. It is typically given orally as a tablet or capsule.

Key Points

• Naltrexone
  • Mechanism
    • Opioid Antagonist
      • Blocks opioid receptors
      • Long acting
        • Depending on the dose, the duration is between 24-72 hours
  • Clinical Use
    • Prevents opioid cravings (Prevents relapse)
      • When taking naltrexone, opioids won’t provide the pleasurable “high” feeling that makes people want to take them
    • May help alcohol cessation
      • Reduces alcohol cravings
    • May help smoking cessation
      • Limited evidence, but may reduce cravings and reward from smoking
  • Side Effects
    • Causes weight loss
    • Naltrexone should not be given within 7 days after last opioid/alcohol use
      • Can precipitate severe withdrawal symptoms in opioid-dependent individuals
  • Administration
    • Given orally
      • The most common form of administration is oral tablets