How Long Before Surgery Should I Stop Naltrexone?

Most clinical guidelines recommend stopping oral naltrexone at least 72 hours before a scheduled surgery, though some sources suggest a window of 24 to 72 hours depending on the procedure and the individual situation. The reasoning centers on giving your opioid receptors enough time to become available again so that pain medications work properly after the operation. But the answer gets more complicated when you factor in extended-release formulations, the risk of relapse for people taking naltrexone to manage alcohol or opioid use disorder, and the reality that the evidence behind these recommendations is thinner than you might expect.

Where the 72-Hour Recommendation Comes From

Naltrexone works by parking itself on your opioid receptors and blocking other molecules from activating them. That is exactly why it helps with addiction: it prevents opioids and, through related pathways, alcohol from producing their rewarding effects. The problem for surgery is that many of the strongest pain medications used during and after an operation are opioids, and they cannot do their job when naltrexone is sitting on the receptors they need to reach.

A review in Current Opinion in Anaesthesiology stated that naltrexone should be held for 72 hours before surgery, while other opioid-based addiction medications like buprenorphine and methadone can typically be continued throughout the perioperative period.¹ A separate BMJ paper on naltrexone and pain management recommended stopping opioid antagonists 24 to 72 hours before elective surgery to allow normal opioid receptor function to return.² The range exists because oral naltrexone’s half-life is roughly four hours, but its active metabolite sticks around longer, and different people metabolize the drug at different speeds. Three days gives a generous cushion for most patients.

A scoping review published in Anesthesiology in 2024 looked at every available article describing how to manage naltrexone around surgery. It found 17 relevant publications, including 13 guideline documents, and every single one recommended stopping naltrexone before the operation. The review also noted something worth paying attention to: none of those guideline documents were built on a systematic literature search or a formal consensus process.³ In other words, the 72-hour figure is widely agreed upon, but it rests more on pharmacological reasoning and clinical experience than on randomized controlled trials testing different stop-times head to head. That does not mean it is wrong. It means the recommendation is the best available guidance rather than a precisely calibrated number backed by large trials.

Oral Naltrexone vs. the Monthly Injection

The 72-hour window applies specifically to the daily oral tablet, which is the most commonly prescribed form. If you receive the extended-release injectable version (sold as Vivitrol in the U.S.), the situation is entirely different. That formulation is designed to release naltrexone slowly from a depot injected into muscle, maintaining blockade for roughly a month. You cannot simply “stop” it the way you can stop taking a pill.

Research in rats treated with extended-release naltrexone showed that the degree of opioid blockade changed substantially over the injection cycle. Early after the injection (around day 4), very high doses of opioids were needed to produce meaningful pain relief, and the blockade was still strong at day 19. By day 39, much lower doses were effective, reflecting the declining drug levels.⁴ While animal data does not translate directly to human dosing, the principle is clear: if your surgery is scheduled shortly after your monthly injection, the blockade will be at its strongest, and your anesthesia team will have fewer options. If it can be timed toward the end of the injection cycle, opioid-based pain relief becomes progressively more feasible.

For elective procedures, many clinicians recommend scheduling surgery as late as possible in the injection cycle and skipping the next scheduled dose. This might mean planning the operation for week four or five after the last injection and not getting a new one. Talk to both the prescribing physician and the surgical team well in advance so the timing can be coordinated. If you are on the injectable form, this is not a decision to make the week before surgery.

How Long the Blockade Actually Lasts

Even after oral naltrexone clears your blood, its effects on opioid receptors can linger. A study testing naltrexone at two dose levels found that a single dose of 100 mg produced complete blockade of hydromorphone’s effects, and the blockade of behavioral effects (the subjective experience of the opioid) persisted for five days after the drug was stopped, even though the blockade of physiological effects faded sooner.⁵ The standard prescribed dose of oral naltrexone is 50 mg daily, not 100 mg, so the five-day figure represents a higher-than-usual dose. Still, it illustrates that the drug’s influence on receptors outlasts its presence in the bloodstream.

This matters practically because 72 hours may be enough for most of the blockade to clear at a standard 50 mg dose, but some residual receptor occupancy can persist, particularly in people who have been taking naltrexone for months. If you are having a procedure expected to produce significant postoperative pain, your anesthesiologist may want a longer lead time or may plan to use higher-than-usual doses of opioids or lean more heavily on non-opioid strategies even after a 72-hour stop.

The Relapse Risk of Stopping

Here is the tension your doctors are navigating: every day you go without naltrexone is a day your addiction treatment is paused. For someone with alcohol use disorder or opioid use disorder, that gap can be dangerous. A paper in Regional Anesthesia and Pain Medicine put it plainly: while the pharmacology of naltrexone suggests that stopping it helps with perioperative pain management, the cessation can significantly increase the risk of relapse, particularly in patients with more severe addiction. The relapse risk has to be weighed against the clinical risk of uncontrolled postoperative pain caused by the blockade.⁶

This is not a hypothetical concern. The perioperative period is already stressful, and stress is a well-known trigger for relapse. If you are told to stop naltrexone three or more days before surgery and then spend additional days recovering before resuming it, you may be without your medication for a week or longer. Some practical steps that can reduce this risk include having a support person aware of the gap, keeping in close contact with your addiction treatment provider, scheduling any counseling or support group sessions around the surgery date, and restarting naltrexone as soon as your surgical team gives the all-clear. Bring up your concerns explicitly with both your surgeon and the prescribing physician. Neither may think to coordinate with the other unless you prompt the conversation.

What Happens in an Emergency

Emergencies do not wait for naltrexone to wear off. If you need surgery right now while the drug is still active, your doctors have options, but the playbook changes. The BMJ review on naltrexone and pain management described several non-opioid strategies for emergency surgery in patients on naltrexone: regional anesthesia (nerve blocks or epidurals that numb a specific area), non-steroidal anti-inflammatory drugs, and ketamine, a dissociative anesthetic that works through a completely different receptor system and is unaffected by naltrexone.²

It is also possible to push through the blockade with higher-than-normal opioid doses, though this requires careful monitoring. The animal study of extended-release naltrexone found that the blockade could be overcome with escalated opioid doses without further depressing breathing or altering movement compared to the placebo group.⁴ In practice, anesthesiologists who encounter a patient on naltrexone in an emergency know to use multimodal approaches: layering regional blocks, non-opioid analgesics, and carefully titrated opioids if needed. The result is manageable, but postoperative pain control tends to be harder, and recovery in the post-anesthesia care unit can take longer. A study of patients undergoing surgery to remove naltrexone implants found that 44% of those under general anesthesia reported moderate to severe pain afterward, and nearly two-thirds of those patients had a prolonged stay in recovery.⁷

The practical takeaway is simple: carry information about your naltrexone use where emergency responders can find it. A medical alert bracelet, a note in your phone’s emergency medical ID, or a card in your wallet can save your anesthesia team valuable time in figuring out why standard pain protocols are not working.

Receptor Changes After Long-Term Use

One lesser-known effect of taking naltrexone for an extended period is that your brain responds to the chronic blockade by growing more opioid receptors. This phenomenon, called receptor upregulation, was demonstrated in research showing that chronic naltrexone administration produced a marked increase in brain opioid receptor density across multiple receptor subtypes.⁸ Your brain is essentially trying to compensate for the fact that its opioid receptors are being blocked by making more of them.

The consequence is that once naltrexone clears, you temporarily have more opioid receptors than someone who was never on the drug, and those receptors are eager to be activated. For someone in recovery from opioid use disorder, this creates an especially dangerous window: if they use opioids after stopping naltrexone, the response can be more intense than expected because of the extra receptors. This heightened sensitivity is a known contributor to overdose deaths in people who stop naltrexone and then relapse.

For surgical purposes, the upregulation effect is a double-edged concern. On one hand, once the naltrexone is gone, opioid pain medications may actually work quite effectively because there are more receptors available. On the other hand, the dose response can be unpredictable, and your anesthesia team needs to titrate carefully rather than jumping to high doses. The study of naltrexone implant removal surgeries noted that perioperative opioid requirements ranged wildly, from zero to the equivalent of 100 mg of intravenous morphine, with the presence of infection at the implant site being the only factor clearly associated with needing more.⁷ The researchers did not observe complications from heightened opioid sensitivity in that group, which is reassuring, but the wide range underscores that there is no one-size-fits-all dose.

Non-Opioid Pain Strategies Worth Discussing

Whether you manage to stop naltrexone in time or not, a multimodal pain plan that relies less on opioids is worth asking your surgical team about. This is increasingly standard practice in modern anesthesia regardless of naltrexone status, but it becomes especially relevant for you. Approaches that work independently of opioid receptors include:

Regional anesthesia: Nerve blocks and epidurals deliver local anesthetic directly to the nerves serving the surgical area. They provide excellent pain control without interacting with naltrexone at all.
Ketamine: Works through NMDA receptors rather than opioid receptors. It is used both during surgery and at lower doses afterward for pain management.
NSAIDs and acetaminophen: Anti-inflammatory drugs like ketorolac (given intravenously) and standard acetaminophen can handle a meaningful portion of postoperative pain, especially when combined with other methods.
Gabapentinoids: Medications like gabapentin or pregabalin are sometimes given before surgery to reduce postoperative pain. They act on calcium channels in the nervous system, not opioid receptors.
Local wound infiltration: The surgeon can inject long-acting local anesthetic directly into the wound at the end of the procedure.

Not every technique is appropriate for every surgery, and you should not expect to choose your own pain protocol. But knowing these options exist lets you have a more informed conversation with your anesthesiologist during the pre-surgical consultation. If your procedure is minor enough that non-opioid methods alone can handle the pain, you and your prescriber may even decide that stopping naltrexone is unnecessary.

How to Coordinate With Your Medical Team

The biggest practical mistake people make is failing to tell their entire surgical team about naltrexone early enough. Your prescribing doctor, your surgeon, and your anesthesiologist all need to be in the loop, and they need to communicate with each other, not just with you. Here is a rough timeline of how the coordination typically works for elective surgery:

Several weeks before: Mention naltrexone at your surgical consultation. If you are on the monthly injection, discuss timing the procedure relative to your injection schedule.
Pre-anesthesia visit: The anesthesiologist assesses your pain management plan. Bring the name, dose, and formulation of your naltrexone. This is when the decision about stopping is finalized.
72 hours before: Stop oral naltrexone, assuming your team has agreed on this timeline. Continue all other medications unless told otherwise.
Day of surgery: Confirm with the anesthesia team that you stopped naltrexone on the agreed date. Mention any cravings or difficulty you experienced during the gap.
After surgery: Restart naltrexone once you no longer need opioid pain medications. Your prescriber can advise on exact timing, which depends on the type and duration of opioids used postoperatively.

If you are taking naltrexone for alcohol use disorder rather than opioid use disorder, the stakes around restarting are a bit different. You do not face the overdose risk associated with opioid relapse, but alcohol relapse during the perioperative period still carries medical risks, including interactions with anesthesia, impaired wound healing, and withdrawal complications in heavy drinkers. The urgency of getting back on naltrexone remains real either way.

When Stopping Might Not Be Necessary

Not every surgery requires opioid pain control afterward. Minor outpatient procedures, certain dental surgeries, and some dermatologic operations can be managed entirely with local anesthetic and over-the-counter pain relievers. In those cases, there may be no reason to interrupt your naltrexone at all. The Anesthesiology scoping review noted that all available guidelines recommended stopping naltrexone before surgery irrespective of dose, indication, or route, but it also pointed out that this blanket recommendation was not based on rigorous evidence.³ For a procedure where opioids would not normally be part of the pain plan anyway, the risk-benefit calculation shifts. Stopping naltrexone exposes you to relapse risk for no clear surgical benefit.

This is a conversation best had directly with your anesthesiologist, who can assess the expected pain level of your specific procedure and decide whether opioid analgesia is even likely to be needed. If the answer is no, continuing naltrexone through the surgery may be the safer overall choice. The evidence base is not strong enough for anyone to give you a definitive rule here, which is exactly why the conversation matters.

Low-Dose Naltrexone and Surgery

A growing number of people take naltrexone at very low doses, typically between 1 and 5 mg, for off-label uses like chronic pain conditions, autoimmune diseases, or fibromyalgia. Low-dose naltrexone operates through a different proposed mechanism than the standard 50 mg addiction-treatment dose: at low doses, the brief, partial blockade of opioid receptors may trigger a rebound increase in the body’s own endorphin production and have anti-inflammatory effects.

The surgical considerations for low-dose naltrexone are less well studied than for the full dose. Because the receptor blockade at these low doses is much shorter-lived and less complete, some clinicians feel comfortable with a shorter discontinuation window or even continuing it. However, there is no published guideline specifically addressing low-dose naltrexone in the perioperative setting. If you are on this regimen, do not assume your anesthesiologist is familiar with it. Bring it up explicitly and be prepared for the possibility that they will recommend stopping it for the same 72-hour window as the standard dose, simply because there is not enough data to do otherwise confidently.

1
PubMed Central. Perioperative and Periprocedural anesthetic management of opioid tolerant patients and patients with active and medically treated opioid use disorder
2
PubMed Central. Naltrexone and problems in pain management
3
PubMed. Perioperative Naltrexone Management: A Scoping Review by the Perioperative Pain and Addiction Interdisciplinary Network
4
PubMed Central. Overriding the blockade of antinociceptive actions of opioids in rats treated with extended-release naltrexone
5
PubMed. Onset, magnitude and duration of opioid blockade produced by buprenorphine and naltrexone in humans
6
Regional Anesthesia and Pain Medicine. Alcohol use disorder in the perioperative period: a summary and recommendations for anesthesiologists and pain physicians
7
PubMed. Adverse events in the removal of naltrexone implants
8
PubMed. Naltrexone-induced opiate receptor supersensitivity