How Long Does Naltrexone Stay in Your System? What to Expect
Quick Answer: Oral naltrexone usually stays in your system for a few days, but its strongest blocking effect often lasts about 24 hours. Injectable naltrexone stays in your system much longer and is designed to keep working for about one month.
At Monterey Bay Recovery, we want to equip you with answers to questions like, “How long is naltrexone in your system?”
Sometimes talking to a real person helps too. Contact us today to compare recovery medication options or learn more about treatment.
How Long Does Naltrexone Stay in Your System After Stopping?
Naltrexone can stay in your system for a few days to about a month, depending on the form you take. The tablet leaves the body faster, while the extended-release injection releases medication slowly over several weeks. So, your chosen method of administration will change the answer to the question, “How long does naltrexone stay in your system?”
This difference matters because naltrexone blocks opioid receptors. That means it can affect how your body responds to opioids, alcohol cravings, and certain medications during the time it remains active.
How Long Does Oral Naltrexone Stay in Your System?
Oral naltrexone usually remains in the body for a few days, though its main effects are often strongest during the first day. Naltrexone has an average half-life of about four hours, while its main active metabolite, 6-beta-naltrexol, has an average half-life of about 13 hours.
A half-life is the time it takes your body to clear about half of a substance. Since it takes several half-lives for a medication to be mostly cleared, oral naltrexone may still be present after the first 24 hours, even if the effects are fading.
How Long Does Injectable Naltrexone Stay in Your System?
Injectable naltrexone stays in your system for about one month because it is made to release slowly. The extended-release injection is typically given every four weeks, or once a month.
This longer timeline can be helpful for people who need steady medication coverage. It also means the medication cannot be quickly removed once injected, so timing and medical guidance are important.
How Long Do the Effects of Naltrexone Last?
The effects of naltrexone may last about 24 hours for the tablet and about one month for the injection. Oral naltrexone is usually taken daily because its blocking effects fade faster, while injectable naltrexone is designed for longer coverage.
For alcohol use disorder, this may help reduce the rewarding effects of drinking. For opioid use disorder, it can block the effects of opioids, which is why a person must be opioid-free before starting it.
What Affects How Long Naltrexone Stays in Your Body?
The form of naltrexone you take affects the timeline more than anything else. Oral tablets clear faster, while the injection stays active longer because of its extended-release design.
Other factors may include your dose, metabolism, liver health, kidney function, age, and overall health. Your prescribing provider can give the safest guidance based on your medical history and substance use history.
How Long After Taking Naltrexone Can You Feel Opioids Again?
Opioids may have reduced or blocked effects while naltrexone is still active in your system. For oral naltrexone, this blocking effect often fades sooner; for injectable naltrexone, it may continue for weeks.
Trying to override naltrexone by taking larger amounts of opioids can be dangerous. Once naltrexone wears off, opioid tolerance may also be lower, which can increase overdose risk if a person returns to opioid use.
What Should You Expect as Naltrexone Leaves Your System?
As naltrexone leaves your system, you may not feel a clear physical change. Naltrexone isn’t an opioid, doesn’t cause a high, and doesn’t usually cause a classic withdrawal syndrome when it wears off.
However, cravings may return as the medication becomes less active. If that happens, it may be a sign that more support is needed, especially if alcohol use, opioid use, or relapse patterns are still hard to manage.
Why Timing Matters Before Starting Naltrexone
Timing matters because taking naltrexone too soon after opioid use can cause sudden withdrawal. For extended-release naltrexone, patients are generally advised to be opioid-free for at least seven to 10 days before starting treatment.
This is especially important for people who have used fentanyl, heroin, prescription pain pills, methadone, or buprenorphine. If opioids are involved, medical supervision can make the process safer.
When Should You Talk to a Professional About Naltrexone?
You should talk to a professional if you’re unsure when naltrexone will wear off, when to start it, or whether it’s safe based on recent substance use. You should also ask for help if cravings return, relapse feels likely, or you’re using alcohol or opioids while trying to stop.
A medication timeline can answer part of the question, but it doesn’t replace a full treatment plan. The right support can help you understand what’s happening in your body and what level of care may fit your situation.
How Monterey Bay Recovery Can Help
We can help you take the next step if your questions about naltrexone are connected to alcohol use, opioid use, cravings, relapse, or detox concerns.
At Monterey Bay Recovery, we provide detox support, residential treatment for drug and alcohol addiction, dual diagnosis care, therapy, and aftercare planning in a retreat-style, six-bed residential setting in Monterey, California. Our goal is to help you move from uncertainty to a clear, realistic path forward.
If you’re worried about medication timing, relapse risk, or whether you need a higher level of care, contact us today to speak with a member of our compassionate team.
FAQs: How Long Does Naltrexone Stay in Your System?
How is naltrexone removed from the body?
Naltrexone is mainly processed by the liver and removed from the body through urine. Because of this, liver function, kidney function, overall health, and other medications may affect how someone processes naltrexone.
Does naltrexone build up in your system?
Naltrexone doesn’t usually build up in the body in the way some medications do when taken as prescribed. However, regular doses can help maintain a consistent level of the medication in your system, which is why it’s important to follow your treatment plan and take it as directed.
How do you know when naltrexone is out of your system?
You may not feel a clear sign when naltrexone is fully out of your system. The best estimate depends on whether you took the pill or injection, when your last dose was, your health history, and guidance from your prescribing provider.
Can naltrexone leave your system faster?
There is no safe, reliable way to force naltrexone out of your system faster. Your body needs time to process the medication, and the extended-release injection can’t be removed once it has been given.
How long does naltrexone stay in your urine?
Naltrexone may be removed through urine after the body processes it, but the exact detection window can vary. Standard drug tests usually don’t look for naltrexone unless a specialized test is ordered.
Is naltrexone still working if you do not feel anything?
Naltrexone can still be working, even if you don’t feel a major physical effect. Many people don’t feel intoxicated, sedated, or noticeably different while taking it, but the medication may still be active in the body.
What happens if you miss a dose of oral naltrexone?
If you miss a dose of oral naltrexone, the blocking effect may weaken as the medication leaves your system. You should follow your prescriber’s instructions instead of doubling up or changing your dose on your own.
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