Most addiction-medicine guidelines do not set a fixed number of months for naltrexone treatment. The American Society of Addiction Medicine states plainly that there is no recommended length of treatment; duration depends on clinical judgment and individual circumstances. In practice, though, many clinicians advise staying on naltrexone for at least twelve months before reassessing, and some people continue the medication indefinitely. The “right” duration turns on what you are treating, how well the medication is working, and whether the risks of stopping outweigh the inconvenience of continuing.
What the Clinical Guidelines Actually Say
If you are looking for a single number, you will not find one in any major treatment guideline. The ASAM’s focused update on opioid use disorder treatment notes that naltrexone duration “depends on clinical judgment and the patient’s individual circumstances,” with no specific endpoint recommended.1Journal of Addiction Medicine. Executive Summary of the Focused Update of the ASAM National Practice Guideline for the Treatment of Opioid Use Disorder That open-endedness can feel unhelpful when you are the one filling the prescription, but it reflects a real truth about addiction treatment: relapse risk varies enormously between individuals, and no single cutoff fits everyone.
For alcohol use disorder specifically, prescribers often anchor on a twelve-month mark. The rationale is that a full year gives enough time to establish new habits, weather seasonal triggers and social situations, and confirm that reduced drinking is stable before removing pharmaceutical support. After that year, the decision about whether to continue typically hinges on whether you have met your drinking goals and sustained them for several months. Some people find that the medication keeps cravings low enough to justify staying on it well beyond a year, and there is no medical reason they cannot do so.
Why Longer Treatment Tends to Produce Better Results
A systematic review and meta-analysis of extended-release naltrexone for alcohol use disorder found that trials lasting longer than three months reported larger reductions in heavy drinking days per month compared with shorter trials.2PubMed. Effect of extended-release naltrexone on alcohol consumption: a systematic review and meta-analysis That does not mean naltrexone suddenly “kicks in” at the three-month mark. Rather, the people who stayed in treatment long enough to be measured at those later time points were benefiting from the cumulative effect of reduced cravings, fewer heavy-drinking episodes, and the behavioral changes that compound over time.
For opioid use disorder, a year-long study of extended-release naltrexone injections tracked quality of life across physical, psychological, social, and environmental domains. The biggest improvements showed up during the 52-week treatment phase, and overall quality of life remained stable through a subsequent year of follow-up after treatment ended.3Drug and Alcohol Dependence. Changes in quality of life during 52 weeks of extended-release naltrexone treatment, subsequent by a 1-year post-treatment period That post-treatment stability is encouraging: it suggests the gains made during a full year of treatment are not immediately lost the moment the medication stops.
The Adherence Problem and Why the Form of Naltrexone Matters
Duration recommendations only matter if people actually take the medication for that long. Adherence to oral naltrexone is notoriously poor. A recent trial comparing oral naltrexone to the once-monthly extended-release injection in hospitalized patients with alcohol use disorder found that only about 27% of the oral group maintained high adherence, compared with roughly 41% in the injectable group. The odds of high adherence were nearly twice as great with the injection.4PubMed Central. Oral vs Extended-Release Injectable Naltrexone for Hospitalized Patients With Alcohol Use Disorder
The reason is straightforward: a daily pill requires a daily decision to keep taking it, and on days when cravings are strong or motivation is low, skipping feels easy. A monthly injection removes that daily decision point. For someone whose treatment plan calls for six to twelve months of naltrexone, the injectable form substantially increases the chance of actually completing that course. If you have tried oral naltrexone before and found yourself quietly stopping after a few weeks, the injection is worth discussing with your prescriber.
Naltrexone Retention Compared With Other Opioid Use Disorder Medications
People being treated for opioid use disorder have a wider medication menu than those with alcohol use disorder, and how long someone stays on naltrexone versus alternatives like methadone or buprenorphine differs sharply. An analysis of Ohio Medicaid data found that naltrexone was associated with a higher risk of discontinuation than both methadone and buprenorphine, and that gap widened over the course of a year.5PubMed. Examining differences in retention on medication for opioid use disorder: An analysis of Ohio Medicaid data
This does not mean naltrexone is a weaker medication. It means it demands more from the patient. Methadone and buprenorphine are both opioid-based treatments that partially satisfy the brain’s opioid receptors, which provides its own motivation to keep taking them. Naltrexone is an opioid antagonist: it blocks those receptors entirely and offers no rewarding effect of its own. Sticking with a medication that does not produce any pleasant sensation requires strong motivation and usually a solid support structure. The takeaway for treatment duration is pragmatic: if you can stay on naltrexone for the recommended period, the outcomes can be very good, but the real-world challenge is getting there.
The Dangerous Window After Stopping
One of the most important reasons to think carefully about when and how you stop naltrexone, particularly for opioid use disorder, is the overdose risk that follows discontinuation. Naltrexone blocks opioid receptors, meaning that while you are on it, you cannot get the usual high from opioids. Over the weeks and months of treatment, your body’s tolerance to opioids drops significantly. If you stop taking naltrexone and then use opioids at the dose your body used to handle, the result can be fatal.
An Australian study examined deaths among people being treated with naltrexone for opioid dependence between 2000 and 2017. Opioid toxicity was the cause of death in roughly 87% of cases, and the majority of those deaths occurred in people who had been maintained on oral naltrexone, suggesting they had stopped taking it or were taking it inconsistently. Cases where naltrexone was not detected in the body at the time of death pointed to the central role of treatment compliance.6PubMed. Circumstances of death of opioid users being treated with naltrexone The lesson here is sobering: the period immediately after stopping naltrexone is arguably the highest-risk window in the entire treatment cycle. Any decision to discontinue should involve a clear safety plan and close follow-up.
Is Naltrexone Safe to Take for Years?
If longer treatment is generally better and stopping carries real risks, the natural follow-up question is whether there is any reason you cannot just stay on naltrexone indefinitely. The short answer: for most people, it appears safe to do so.
The most commonly cited long-term concern involves the liver. Naltrexone’s prescribing information carries a boxed warning about the potential for liver damage at high doses, a warning based on early studies in which the drug was given at doses several times higher than those used for addiction treatment. In a long-term study of extended-release naltrexone injections for opioid dependence, about 17% of patients had elevations in liver function tests, but none of those elevations were judged to be clinically significant.7PubMed. Injectable extended-release naltrexone (XR-NTX) for opioid dependence: long-term safety and effectiveness A separate study examining high-dose naltrexone in the context of eating disorders found no adverse changes in liver function at all.8PubMed. High-dose naltrexone and liver function safety At standard addiction-treatment doses, the evidence suggests the liver risk is minimal, though your prescriber will likely want to check liver enzymes periodically, especially in the first few months.
Beyond the liver, naltrexone’s side-effect profile is relatively mild compared with other addiction medications. Common complaints include nausea, headache, and fatigue, which usually diminish after the first few weeks. The injection-site reaction associated with the monthly shot can be uncomfortable but is rarely serious. Nothing in the long-term data suggests that taking naltrexone for two, five, or even ten years produces new or worsening adverse effects.
Stopping Naltrexone Does Not Require a Taper
Unlike many psychiatric medications and all opioid-based addiction treatments, naltrexone does not produce physical dependence. The ASAM guideline specifically notes that it can be stopped abruptly without withdrawal symptoms.1Journal of Addiction Medicine. Executive Summary of the Focused Update of the ASAM National Practice Guideline for the Treatment of Opioid Use Disorder There is no need for a gradual dose reduction, and no rebound syndrome to worry about from the medication itself. The risk lies entirely on the addiction side: when the pharmacological block on cravings or opioid effects is removed, the underlying disorder is still there. That is why the timing and context of stopping matter more than the mechanics of how you taper off.
When clinicians say a patient is “ready” to stop, they generally mean that the person has met their treatment goals and maintained them consistently for several months, has strong coping strategies in place, and has a support system to catch early signs of relapse. A rushed discontinuation, for instance because of cost, inconvenience, or feeling “cured” after a few good months, is where things most often go wrong.
The Targeted Approach: Taking Naltrexone Only When You Need It
Not everyone takes naltrexone every day. A treatment model sometimes called “targeted” or “as-needed” use involves taking the medication only in situations you identify as high risk for heavy drinking, say before a party, a stressful work dinner, or a weekend trip where alcohol will be flowing. A trial testing this strategy found that targeted naltrexone reduced heavy drinking, particularly among men, though the overall effect was modest enough that researchers suggested combining it with additional behavioral strategies for the best results.9PubMed Central. Targeted naltrexone for problem drinkers
This approach changes the “how long” question entirely. Instead of asking “when should I stop?” you are asking “when should I take it?” Some people use targeted naltrexone for years with no plan to stop, simply reaching for it the way someone might reach for an antihistamine during allergy season. For people whose drinking is episodic rather than daily, this can be a more sustainable and less burdensome strategy than committing to a daily pill or monthly injection.
Who Ends Up Staying on Naltrexone Longest
Research into who continues naltrexone beyond an initial prescription reveals a somewhat counterintuitive pattern. A study of veterans with alcohol use disorder found that continued use of naltrexone was associated with factors like homelessness, major depression, schizophrenia, use of other psychiatric medications, and psychiatric hospitalization.10PubMed. Multiple Psychiatric Morbidity and Continued Use of Naltrexone for Alcohol Use Disorder In other words, people with the most complex and severe psychiatric profiles were the ones most likely to stay on the medication long term. This makes clinical sense: the more co-occurring conditions a person has, the higher their relapse risk, and the more a prescriber will lean toward indefinite treatment. It also means that the “typical” naltrexone patient in a study of long-term users may not look much like you if your situation is less complicated.
Naltrexone in Surgical and Acute Pain Situations
One practical issue that rarely comes up in conversations about treatment duration but catches people off guard: what happens if you need surgery or experience acute pain while on naltrexone? Because naltrexone blocks opioid receptors, standard opioid painkillers like morphine, oxycodone, and fentanyl become far less effective. Multiple studies have confirmed that patients on naltrexone require substantially higher doses of opioids for postoperative pain control, and in some cases opioids simply will not work at all until the naltrexone clears the system.11PubMed. Treatment of Acute Pain in Patients on Naltrexone: A Narrative Review
For oral naltrexone, which clears the body within a few days, this is manageable with advance planning. You stop the medication before a scheduled surgery and coordinate with your treatment team. For the monthly injection, the situation is trickier: the drug stays active for roughly four weeks, and there is no way to remove it early. Non-opioid pain management, including regional anesthesia, ketamine, and anti-inflammatory medications, becomes the primary strategy. If you are on long-term naltrexone and have an upcoming surgery, bring this up early in your surgical planning. It is not a reason to avoid naltrexone, but it is a reason to carry a medical alert card and make sure every provider on your care team knows.
Naltrexone for Methamphetamine Use Disorder
Although naltrexone is FDA-approved only for alcohol and opioid use disorders, researchers are exploring its use for other substances. A trial published in the New England Journal of Medicine tested extended-release naltrexone injections combined with oral bupropion in adults with methamphetamine use disorder. The response rate was low overall, but it was higher in the treatment group than in the placebo group over a twelve-week period.12PubMed Central. Bupropion and Naltrexone in Methamphetamine Use Disorder This is still early-stage evidence, and the effect was modest enough that the combination is far from a standard treatment. But for a condition with essentially no approved pharmacotherapy, even a modest signal is worth noting. If you are prescribed naltrexone off-label for stimulant use, the duration question is even less settled than it is for alcohol or opioids, and the decision will rely heavily on whether you and your prescriber observe a meaningful benefit.
How to Talk to Your Prescriber About Duration
Given the absence of a universal timeline, the most productive conversation with your prescriber starts not with “how long?” but with “what are my goals and when will we know I have reached them?” For alcohol use disorder, that might mean consistently staying within your target number of drinks per week for six months. For opioid use disorder, it might mean sustained abstinence confirmed by urine screens, stable housing, and engagement in counseling. Defining those benchmarks early turns the vague concept of “long enough” into something measurable.
You should also ask about the plan for after discontinuation. Will there be more frequent check-ins? A lower threshold for restarting the medication if cravings return? A backup plan for high-risk periods like holidays or life transitions? The evidence consistently shows that the risk of relapse rises when the medication stops, and that risk is highest in the first few months afterward. A prescriber who simply says “okay, you can stop now” without a follow-up plan is leaving the most dangerous part of the process unaddressed. Treatment duration is only half the question; what happens next is the other half.