Naltrexone can stay in your system for up to 50 days if you’re injecting it. However, if you’re taking this medication in pill form, it may be cleared from your body within a day or two. Ultimately, the answer to the question “How long does naltrexone stay in your system?” depends on various individual factors, ranging from the method of administration to dosage and your overall health condition.
Anyone who takes naltrexone—whether for opioid or alcohol dependence treatment—should be informed about its clearance time, as this can help prevent dangerous drug interactions and relapse.
Keep reading to learn more about this medication and the factors that determine how long it stays in your system.
What Is Naltrexone, and What Is It Used For?
Naltrexone is an opioid antagonist medication used for opioid use disorder (OUD) treatment available as a pill (ReVia®) or extended-release injection (Vivitrol®). Oral vs. injectable naltrexone forms differ in terms of usage; the pill is typically taken once daily, whereas the injection is administered once a month. It can also be used for alcohol use disorder (AUD).
While naltrexone is one of the three FDA-approved medications for OUD treatment, it differs from the other two—methadone and buprenorphine—in that it is not an opioid. It does not replace one opioid with another or lead to opioid abuse, dependence, and drug addiction. You also won’t experience naltrexone withdrawal symptoms after quitting this drug.
Naltrexone is used to curb cravings, prevent relapse, and help individuals undergoing opioid addiction treatment remain opioid-free. Note that even though it can support long-lasting recovery from opioid dependence, it is only effective under specific circumstances—namely, when used as part of a comprehensive opioid dependence treatment.
Do not attempt to take naltrexone without medical supervision, as it can be very dangerous.
Importantly, initiating naltrexone therapy should be timed precisely; otherwise, this medication can trigger precipitated withdrawal symptoms. In most cases, patients should remain opioid-free for 7–10 days before starting naltrexone treatment.
How Does Naltrexone Affect Your Body?
Naltrexone affects the body by interacting with opioid receptors located throughout the central nervous system (CNS). However, it works differently from opioid agonists, such as methadone, which activate these receptors.
Instead of activating opioid receptors, naltrexone blocks them and inhibits the euphoric and analgesic effects of opioids. Therefore, you will not get “high” if you use opioids while taking naltrexone.
The onset of its effects depends on the formulation, but it typically begins to work within 30 minutes to two hours after consumption. Depending on the dose, the effects of oral naltrexone last 24–72 hours. Meanwhile, injections remain effective for around a month.
Naltrexone Half-Life
The half-life of naltrexone ranges from four hours to ten days, meaning it can take anywhere between several hours to over a week for your body to eliminate half a dose of this drug.
Its half-life primarily depends on the administration method; it takes significantly longer for naltrexone injections to leave the body due to their extended-release mechanism.
The half-life of oral naltrexone is around four hours, but its metabolites may have a longer half-life (for example, it can take 11–13 hours to reduce the concentration of its active metabolite 6β-naltrexone by 50%). Meanwhile, the half-life of naltrexone injections varies between five and ten days.
Now that we’ve discussed the basics, let’s move on to the question, “How long does naltrexone stay in your system?”
How Long Does Naltrexone Stay in Your System?
Depending on the route of administration and other individual factors, naltrexone can stay in your system between 1 and 50 days or even longer. This is because it takes roughly four or five half-lives to clear drugs.
If you have an upcoming drug test, naltrexone use isn’t something you should be worried about. Standard drug tests don’t test for it, as this drug doesn’t lead to substance abuse and is not a controlled substance. Instead, it is used to treat opioid and alcohol use disorders. Therefore, there are no legal repercussions for using it.
With this in mind, let’s find out how long naltrexone remains detectable in blood, hair, saliva, and urine samples:
How Long Does Naltrexone Stay in Blood?
Oral naltrexone stays in the blood for around 24 hours, whereas extended-release formulations may be detected for several weeks or months after the last dose.
How Long Does Naltrexone Stay in Hair?
Naltrexone stays in hair and can be detected by hair follicle tests for 90 days after taking the last dose. These tests have the longest detection window for most drugs, and naltrexone is no exception. In some cases, traces of this medication may remain in hair follicles even longer than that.
How Long Does Naltrexone Stay in Saliva?
Naltrexone stays in saliva for about 24 hours after administration, meaning it will show up in saliva samples for up to one day in most cases. Traces of extended-release naltrexone, however, may be detected beyond this time frame.
How Long Does Naltrexone Stay in Urine?
Oral naltrexone stays in urine for only 4–6 hours after your last dose. Although urine tests have the shortest detection window, injectable naltrexone may show up on such drug tests for much longer.
Unlike oral naltrexone, extended-release naltrexone can be detected months after last use because it is cleared from the body at a much slower rate.
Now that you have a general idea of how long naltrexone stays in your system, let’s explore the factors that may affect this.
5 Main Factors That Determine How Long Naltrexone Stays in Your System
The four main factors that determine how long naltrexone stays in your system are administration method, dosage, metabolism, overall health condition, and polydrug use.
Here’s how each of these methods affects the clearance of naltrexone:
Method of Administration
The method of administration is a key factor that impacts how long naltrexone stays in your system. Injectable formulations have a considerably longer duration of action—up to a month—than oral formulations.
Naturally, individuals using naltrexone injections will require significantly more time to eliminate it than those taking it in pill form.
Dosage
How long naltrexone stays in your system also depends on the dosage. The higher the dosage, the longer it will take to clear it.
Metabolism
The slower your metabolism is, the longer it will take to clear naltrexone. Factors that affect your metabolic rate, such as age and physical activity, can also impact how long this medication stays in your system.
Furthermore, it may take longer for naltrexone to leave your system if you have a high body fat percentage. This is because its metabolites may collect in fatty tissues, which can prolong its clearance.
Health Condition
Certain medical conditions can impact your body’s ability to eliminate drugs. The metabolism of naltrexone primarily takes place in the liver. Therefore, people with impaired liver function might need more time to process and eliminate this drug than others.
Other health conditions, such as chronic diseases or kidney problems, can also impact how long naltrexone stays in your system.
Simultaneous Substance Use
The use of other drugs besides naltrexone can make it harder for your body to metabolize and eliminate it. In particular, medications that alter hepatic metabolism can impact its clearance, as they may cause increased or decreased naltrexone serum concentrations.
Do not take naltrexone with other substances your doctor hasn’t approved of, as it can lead to dangerous drug interactions.
ANR Opioid Dependence Treatment
Accelerated Neuro-Regulation (ANR) is a groundbreaking treatment developed by Dr. Andre Waismann that has helped over 25,000 people worldwide conquer opioid dependence within a matter of days.
ANR treatment differs from traditional methods in that it attacks the root of the problem rather than merely managing its symptoms. This treatment achieves its therapeutic goal—neuro-equilibrium—by re-regulating the endorphin-receptor system imbalance resulting from prolonged opioid use.
Put simply, ANR helps the body clear opioids while allowing it to resume proper endorphin production, thereby restoring the nervous system to its pre-dependence state.
Benefits of Undergoing ANR Treatment
The main benefits of undergoing ANR treatment are:
- Safety. Patient safety is our absolute priority. Therefore, ANR is always performed in an ICU setting of accredited hospitals with state-of-the-art medical equipment by a team of highly experienced board-certified healthcare professionals.
- Long-lasting results. ANR treatment supports lasting success by addressing the neurobiological root of opioid dependence. Plus, Accelerated Neuro-Regulation utilizes naltrexone as opposed to opioid-replacement drugs like Suboxone, allowing you to achieve complete freedom from opioids.
- Personalized approach. Unlike traditional approaches, ANR is not a one-size-fits-all treatment. It is suitable even for those with co-occurring health conditions, as each patient receives a treatment plan tailored to their unique medical history and needs.
Ready to break free from opioid dependence once and for all? Contact us today for a free, 100% confidential consultation with no obligation.
Key Takeaways
The bottom line is that there’s no single answer to “How long does naltrexone stay in your system?” that applies to everyone taking it. If you want to determine the rate at which your body will clear it, your best option is to consult your doctor.
Before you leave, let’s go over the key points we covered today:
- Since naltrexone’s half-life ranges between 4 hours and 10 days, it can take anywhere between a couple of days and a couple of months to clear it.
- Some of the main factors that determine how long naltrexone stays in your system are the method of administration, dosage, and metabolism.
- ANR is an ultra-modern treatment that supports long-lasting recovery by eradicating the root of opioid dependence.
How Long Does Naltrexone Stay in Your System FAQ
It can take between a day and over a month for naltrexone to leave your system, depending on the administration method, dosage, your health condition, and other factors.
Naltrexone’s effectiveness lasts from one day to a month. The duration of its effects largely depends on its formulation; oral naltrexone works for 24–72 hours, whereas naltrexone injections are effective for roughly a month.
Whether naltrexone is short- or long-acting depends on its formulation. Long-acting naltrexone comes as an injection that should be administered once per month. It also comes in tablets that are typically taken once daily.
Naltrexone is different from Suboxone and methadone because it is not an opioid. Therefore, it blocks opioid receptors instead of activating them and doesn’t cause rewarding effects, such as euphoria. It also doesn’t have any potential for abuse and addiction, which isn’t the case with other medications used for opioid dependence treatment.
Naltrexone will not show up on a drug test unless it is specifically designed to detect it. In rare cases, however, oral naltrexone—or, rather, its metabolite noroxymorphone—can cause a false positive urine drug screen for oxycodone.
