What is naltrexone used for?
In psychiatry/addiction care, naltrexone is used for alcohol use disorder (to reduce cravings and heavy drinking) and opioid use disorder (to block opioid effects and reduce relapse risk after detox). It’s not a sedative and it’s not addictive.
Can I start naltrexone if I’m still drinking?
Yes, many clinicians start it while someone is still drinking. You don’t have to be abstinent first for alcohol use disorder. The bigger issue is making sure you’re not using opioids—because opioids plus naltrexone can trigger sudden withdrawal.
How long do I need to be opioid-free before starting?
Typically at least 7 to 10 days opioid-free (including tramadol). If you were on long-acting opioids like methadone or buprenorphine, some people need up to 14 days. When there’s any doubt, a supervised start and/or naloxone challenge can help confirm you’re truly opioid-free.
What happens if I take opioids while on naltrexone?
You may feel little to nothing because the receptors are blocked. The dangerous part is people trying to override the block by taking larger doses—that can cause overdose and death, especially as the medication wears off or after stopping when tolerance is lower.
Is Vivitrol stronger than oral naltrexone?
It’s not really about “stronger.” Vivitrol is long-acting and removes the daily pill decision, which can be a huge advantage. Oral naltrexone works well when adherence is strong. The best choice is usually the one you can realistically stick with.
What are the most common side effects?
Nausea is the classic one, especially early. Headache, dizziness, sleep problems, and anxiety/restlessness can happen too. With Vivitrol, injection-site reactions are common—anything severe, worsening, or associated with fever, drainage, or skin breakdown needs urgent evaluation.
Does naltrexone affect mood?
It can. Depression and suicidal thoughts have been reported, including postmarketing reports. If mood gets darker, you feel hopeless, or you have suicidal thoughts, treat it like a real emergency and reach out immediately.
Is naltrexone hard on the liver?
It can raise liver enzymes, usually mildly and sometimes transiently. Rarely, more serious hepatitis-type injury has been reported. That’s why baseline and periodic liver tests are standard, and why clinicians avoid starting it during acute hepatitis or liver failure.
What if I need surgery or strong pain medication?
Plan ahead. If opioid pain meds might be needed, oral naltrexone is typically stopped at least 72 hours before elective surgery. With Vivitrol, you generally need about 30 days after the last injection for opioid responsiveness to return. Always tell surgeons, dentists, and ER clinicians you’re on naltrexone.
Do I need to taper off naltrexone?
No taper is required. But stopping changes your risk profile—especially in opioid use disorder—because tolerance drops and overdose risk can rise if relapse occurs. If you stop, you should also have a clear relapse prevention plan and naloxone access if opioids are part of your history.
Can naltrexone be used for methamphetamine use disorder?
Sometimes off-label, usually as part of combination treatment in specialty addiction care (often paired with bupropion). It’s not a guaranteed fix, but it may provide modest benefit for some people when combined with therapy and structured support.