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Full-dose naltrexone tablets on a matte clinical surface
DoseRoutine Naltrexone (Full Dose) — Full-dose naltrexone tablets on a matte clinical surface. Original DoseRoutine photography.
medicationInjectablePrescription only (US)Full-dose naltrexone (oral 50 mg and extended-release 380 mg injectable) is FDA-approved for alcohol use disorder and for prevention of relapse to opioid dependence following opioid detoxificationThis record covers full therapeutic dosing only, not low-dose naltrexone (LDN) protocols, which use different doses and are studied for different indications

Naltrexone (Full Dose)Benefits, Dosage & Interactions

Also known as: Vivitrol, ReVia

Naltrexone is a medication primarily used in the management of alcohol dependence and opioid dependence. It functions as an opioid antagonist, meaning it blocks the effects of opioid drugs. It is typically taken in the morning. The reported plasma half-life is about 4 hours, which shapes dosing frequency.

How much Naltrexone (Full Dose) do people take?

Oral full-dose naltrexone was used at 50 mg once daily in the alcohol-dependence trials cited; extended-release injectable naltrexone was dosed at 380 mg intramuscularly once monthly in the opioid and hospitalized alcohol-use-disorder trials. Route reported: Oral tablet (50 mg) or intramuscular extended-release injection (380 mg), depending on the trial arm. Frequency reported: Once daily for oral dosing; once monthly for the extended-release injectable form. These are amounts documented in the cited studies and labels for Naltrexone (Full Dose) — they are reported for reference, not a recommendation. Regulatory status differs by country, including between the US (FDA) and Canada (Health Canada). Confirm any amount with a licensed clinician before you take it.

See the full reported protocol and its sources

Researched by DoseRoutine Research TeamReviewed for accuracy by Nicholas Alexander, RSE, SO, PMPLast updated Educational reference only — not medical advice. Always confirm dosing and safety decisions with a licensed clinician.

Evidence: Strong — 4 human randomized trials and regulatory approval on file.
Evidence strengthStrong · 4/4
PreclinicalStrong human evidence

4 human randomized trials and regulatory approval on file.

Plasma half-life
~4 h
Typical timing
in the morning
Default unit
mg

What published protocols report

Ranges documented in the literature, shown for reference. DoseRoutine does not recommend an amount — your prescriber or the product label sets the dose.

Reported amounts
Oral full-dose naltrexone was used at 50 mg once daily in the alcohol-dependence trials cited; extended-release injectable naltrexone was dosed at 380 mg intramuscularly once monthly in the opioid and hospitalized alcohol-use-disorder trials[1][2][3][4]
Route studied
Oral tablet (50 mg) or intramuscular extended-release injection (380 mg), depending on the trial arm[1][2][3][4]
Frequency
Once daily for oral dosing; once monthly for the extended-release injectable form[1][2][3][4]
Cycle length
Treatment periods of 16 weeks (COMBINE), 24 weeks (X:BOT), and shorter inpatient-to-outpatient bridges in the hospitalized-patient trial[1][2][3][4]
Half-life
Not reported directly in the cited trials[1][2][3][4]

Reported for Naltrexone (Full Dose) in the cited sources. Published ranges are not dosing advice.

Mixing Naltrexone (Full Dose): bacteriostatic water and syringe units

The vial arrives as dry powder. How much water you add sets the strength, and the strength sets the mark you draw to on the syringe. The table assumes a 5 mg vial and a 250 mcg example draw on a U-100 insulin syringe, where 100 units is one millilitre. If your vial is a different size, scale it — the arithmetic is the same.

Bacteriostatic water addedResulting strength250 mcg draws to
1 mL5 mg/mL5 units
2 mL2.5 mg/mL10 units
3 mL1.67 mg/mL15 units

Units, not millilitres. Insulin syringes are marked in units, and mixing up mcg and mg on a peptide label is the single most common error people report. Check the label twice. Run your own vial through the calculator.

Storage and stability

Before mixing
Sealed and still as a dry powder, Naltrexone (Full Dose) vials are normally kept in the fridge at 2–8 °C, out of light. Short spells at room temperature during shipping are the norm for lyophilized peptides and are not, on their own, a sign the vial is spoiled.
After mixing
Once bacteriostatic water goes in, the vial belongs in the fridge and is generally treated as good for about 28 days — that is how long the benzyl alcohol in bacteriostatic water is relied on to hold back bacterial growth. Plain sterile water has no preservative, so a vial mixed with it is a single-session vial. Never freeze a reconstituted vial.
When to throw it out
A properly mixed vial is clear. Cloudiness, floating strands, a color change or powder that will not go into solution after gentle swirling all mean the vial should be discarded rather than used. Shaking a peptide vial hard is the usual cause — swirl it, or run the water down the inside wall of the vial instead of onto the powder.

Handling and shelf-life figures describe general practice for lyophilized peptides. They are not a dose and not medical advice — your prescriber or the product label sets the amount.

References & evidence

Documents the Naltrexone (Full Dose) entry is written from. Each number matches an inline marker above.

  1. [1]Combined pharmacotherapies and behavioral interventions for alcohol dependence: the COMBINE study: a randomized controlled trialAnton RF, O'Malley SS, Ciraulo DA, Cisler RA, Couper D, Donovan DM · JAMA · 2006 · Peer-reviewed · PMID 16670409
  2. [2]Comparative effectiveness of extended-release naltrexone versus buprenorphine-naloxone for opioid relapse prevention (X:BOT): a multicentre, open-label, randomised controlled trialLee JD, Nunes EV Jr, Novo P, Bachrach K, Bailey GL, Bhatt S · The Lancet · 2018 · Peer-reviewed · PMID 29150198
  3. [3]Oral vs Extended-Release Injectable Naltrexone for Hospitalized Patients With Alcohol Use Disorder: A Randomized Clinical TrialMagane KM, Dukes KA, Fielman S, Palfai TP, Regan D, Cheng DM · JAMA Internal Medicine · 2025 · Peer-reviewed · PMID 40257810
  4. [4]Naltrexone for alcohol dependence: a randomized controlled trialMorris PL, Hopwood M, Whelan G, Gardiner J, Drummond E · Addiction · 2001 · Peer-reviewed · PMID 11784454

References & Evidence

Sources on this page that document Naltrexone (Full Dose) dosing, timing and safety.

  1. [1]National Center for Biotechnology Information View source
  2. [2]U.S. National Library of Medicine View source

Educational information only — not medical advice. Dose ranges vary by person, indication and prescriber.

What is Naltrexone (Full Dose)?Sources for this section: Jumps to this entry in the sources and references list at the end of the page.

Naltrexone is a medication primarily used in the management of alcohol dependence and opioid dependence. It functions as an opioid antagonist, meaning it blocks the effects of opioid drugs. In the context of alcohol dependence, it is thought to reduce the craving for alcohol and the rewarding effects of drinking, thereby supporting abstinence or reducing heavy drinking. For opioid dependence, it prevents euphoric effects and helps maintain abstinence after detoxification. Naltrexone is available in oral tablet form and as an extended-release injectable formulation (Vivitrol). The full dose typically refers to the oral administration, which generally involves a higher daily amount compared to low-dose naltrexone (LDN). It is important to note that naltrexone is not a narcotic and is not addictive. It does not produce a euphoric effect. Treatment with naltrexone should always be part of a comprehensive management program that includes counseling and psychosocial support, as emphasized by the Substance Abuse and Mental Health Services Administration (SAMHSA).

What does the research say about Naltrexone (Full Dose)?

Tap a section to expand.

Naltrexone acts as a competitive antagonist at opioid receptors in the central nervous system. Its primary mechanism involves binding to mu (µ), kappa (κ), and delta (δ) opioid receptors, with a particularly high affinity for the mu-opioid receptor. By binding to these receptors, naltrexone effectively blocks exogenous opioids (like heroin, morphine, or oxycodone) from attaching and exerting their effects. This blockade prevents the euphoric and analgesic effects that opioid drugs typically produce. In the treatment of alcohol dependence, the precise mechanism is not fully understood, but it is believed that naltrexone modulates endogenous opioid systems that are involved in the rewarding effects of alcohol consumption. Alcohol ingestion leads to the release of endorphins, which activate opioid receptors and contribute to the pleasurable aspects of drinking. Naltrexone's blockade of these receptors reduces the reinforcing properties of alcohol, thereby decreasing cravings and the desire to drink. This leads to a reduction in the rate of relapse to heavy drinking and an increase in abstinence. The active metabolite, 6-beta-naltrexol, also contributes to its therapeutic effects and has a longer half-life than naltrexone itself, as described by DrugBank.

Source for this section: Sources for How does Naltrexone (Full Dose) work?: Jumps to this entry in the sources and references list at the end of the page.

Naltrexone's primary therapeutic benefits are in the treatment of opioid dependence and alcohol dependence, as supported by numerous clinical studies. * **Opioid Dependence:** For individuals who have successfully undergone detoxification from opioids and are opioid-free, naltrexone helps prevent relapse by blocking the effects of any opioids that might be consumed. If a person takes opioids while on naltrexone, they will not experience the typical euphoric or pain-relieving effects, which can remove the incentive for opioid use. This can be a crucial tool in maintaining long-term abstinence, particularly when combined with behavioral therapies. The FDA label for naltrexone highlights its use in preventing relapse to opioid dependence. * **Alcohol Dependence:** Naltrexone has been shown to reduce both the craving for alcohol and the amount of alcohol consumed by individuals with alcohol dependence. It can decrease the 'rewarding' sensation associated with drinking, making it less appealing. Clinical trials, as summarized by organizations like the National Institute on Alcohol Abuse and Alcoholism (NIAAA), demonstrate that naltrexone can increase the rate of abstinence and decrease the number of heavy drinking days in individuals actively seeking treatment for alcohol use disorder. It does not cause aversive reactions to alcohol, unlike disulfiram.

The efficacy of naltrexone in treating opioid and alcohol dependence is well-established through extensive research. For alcohol dependence, a Cochrane review found that naltrexone significantly reduced the risk of relapse to heavy drinking and decreased alcohol craving. The evidence consistently supports its role as an effective pharmacotherapy. Studies often show that patients treated with naltrexone have fewer relapses and more days of abstinence compared to placebo when used as part of a comprehensive treatment program, as observed in research published in journals indexed by PubMed. In opioid dependence, naltrexone's effectiveness in maintaining abstinence post-detoxification has been demonstrated in multiple clinical trials. Its ability to block the effects of exogenous opioids is a key factor. An important consideration is patient adherence, as the medication is only effective when taken consistently. The extended-release injectable form was developed in part to address adherence challenges in opioid-dependent individuals. The evidence base, including numerous randomized controlled trials, underscores naltrexone's position as an FDA-approved treatment for both conditions. Data from the Substance Abuse and Mental Health Services Administration (SAMHSA) further emphasizes its role in medication-assisted treatment (MAT) protocols.

Like all medications, naltrexone can cause side effects. These are typically mild to moderate and often subside with continued use. Common reported side effects include: * Nausea, vomiting, diarrhea, or constipation * Headache * Dizziness or lightheadedness * Anxiety or nervousness * Difficulty sleeping (insomnia) * Fatigue or decreased energy * Joint and muscle pain * Abdominal pain Less common but more serious side effects can include liver damage (though rare at typical doses, liver function tests may be monitored), depression, and suicidal thoughts or behavior. Allergic reactions, though rare, can also occur. Patients should discuss any side effects with their healthcare provider. This is educational information, not medical advice — consult a qualified clinician before starting, stopping or combining any compound.

Source for this section: Sources for What are the side effects of Naltrexone (Full Dose)?: Jumps to this entry in the sources and references list at the end of the page.

Naltrexone should be used with caution under specific circumstances. There is a risk of precipitated opioid withdrawal if naltrexone is administered to individuals who are currently physically dependent on opioids. This withdrawal can be severe, requiring medical attention. Therefore, patients must be opioid-free for a sufficient period (typically 7-10 days for short-acting opioids and potentially longer for long-acting opioids or buprenorphine) before initiating naltrexone therapy. Healthcare providers typically confirm opioid-free status with a urine drug screen and by observing the patient for signs of withdrawal. Furthermore, individuals taking naltrexone may be more sensitive to opioids if they try to overcome the blockade by taking very large doses; this can lead to opioid overdose, respiratory depression, coma, or death. Naltrexone can cause liver injury in rare instances, particularly with excessive doses, though the risk is low at recommended therapeutic doses. Liver function tests may be monitored in some patients, as advised by the prescribing information. It is also important to consider the potential for depression and suicidal ideation, particularly in vulnerable populations. This is educational information, not medical advice — consult a qualified clinician before starting, stopping or combining any compound.

Source for this section: Sources for Who should avoid Naltrexone (Full Dose)?: Jumps to this entry in the sources and references list at the end of the page.

Naltrexone is contraindicated in several situations to ensure patient safety: * **Current Opioid Use:** It must not be given to patients currently using opioid analgesics or those in acute opioid withdrawal, as it will precipitate severe withdrawal symptoms. * **Positive Opioid Screen:** Individuals who have failed the naloxone challenge test or have a positive urine screen for opioids should not receive naltrexone. * **Opioid Dependence Without Detoxification:** Patients who are opioid-dependent but have not undergone detoxification are contraindicated. * **Hypersensitivity:** A known hypersensitivity to naltrexone, 6-beta-naltrexol, or any inactive ingredients in the formulation, as defined by the FDA label, is a contraindication. * **Acute Hepatitis or Liver Failure:** Due to the potential for hepatotoxicity, naltrexone is contraindicated in patients with acute hepatitis or existing liver failure. Liver function should be assessed before initiation of therapy in such cases. This is educational information, not medical advice — consult a qualified clinician before starting, stopping or combining any compound.

Source for this section: Sources for When should Naltrexone (Full Dose) not be taken?: Jumps to this entry in the sources and references list at the end of the page.

When considering medications, certain combinations with naltrexone require careful consideration or are contraindicated due to potential interactions or safety concerns. * **Opioid Pain Medications:** Naltrexone completely blocks the effects of opioid medications used for pain relief (e.g., codeine, hydrocodone, morphine, oxycodone, fentanyl). If a patient on naltrexone needs pain management, non-opioid options should be considered first. In emergency situations requiring opioids, higher-than-usual doses may be needed to overcome the naltrexone blockade, increasing the risk of respiratory depression and other opioid-related adverse events after the naltrexone effects wear off. * **Other Opioid Agonists/Antagonists:** Medications like buprenorphine (used for opioid dependence treatment) in combination with naltrexone can cause complex interactions including precipitated withdrawal symptoms if not managed carefully by a clinician. A naloxone challenge test may be performed to assess for opioid dependence before starting naltrexone. This is educational information, not medical advice — consult a qualified clinician before starting, stopping or combining any compound.

Source for this section: Sources for What should you not mix with Naltrexone (Full Dose)?: Jumps to this entry in the sources and references list at the end of the page.

Naltrexone oral tablets are typically taken once daily. The dose is user-directed and must be set by a licensed clinician. Some clinicians may initiate treatment with a lower dose for a few days to assess tolerability before increasing to the full daily dose, a practice sometimes referred to as 'dose titration'. It can be taken with or without food, though taking it with food may help reduce gastrointestinal upset such as nausea, as noted in patient information guides. Consistency in taking the medication is important for its effectiveness. The extended-release injectable formulation is administered once a month by a healthcare professional.

Source for this section: Sources for When should you take Naltrexone (Full Dose)?: Jumps to this entry in the sources and references list at the end of the page.

Put it into practice

Reading about Naltrexone (Full Dose) is the first step — DoseRoutine helps you act on it. These free tools turn what you just learned into a routine.

What interacts with Naltrexone (Full Dose)?

Documented interactions for Naltrexone (Full Dose): the other compound, the severity and confidence of the interaction, what happens, and what to do.
Interacts withSeverityTypeWhat happensWhat to do
Any supplement + medicationNoteCategory ruleConfidence: theoreticalSome supplements change how the body processes medications (absorption, liver enzymes, or additive effects).Source for this interaction: Jumps to this entry in the sources and references list at the end of the page.Specific pairs are checked against a licensed drug database and shown with their own severity. Always confirm with your provider or pharmacist.
Any vitamin + medicationNoteCategory ruleConfidence: theoreticalCertain vitamins interact with specific medications (e.g., vitamin K with blood thinners).Source for this interaction: Jumps to this entry in the sources and references list at the end of the page.Specific pairs are checked against a licensed source; confirm with your provider.

Frequently asked questions about Naltrexone (Full Dose)

Full-dose naltrexone (typically 50 mg daily orally or 380 mg monthly via injection) is used to treat opioid and alcohol dependence by blocking opioid receptors. Low-dose naltrexone (LDN, typically 1.5–4.5 mg daily) is an off-label use often explored for chronic pain and autoimmune conditions, where its presumed mechanism involves modulating the immune system and increasing endorphin release by briefly blocking opioid receptors. These are distinct uses with different mechanisms and clinical applications.

Yes, you can still feel pain. Naltrexone specifically blocks the effects of opioid pain relievers. Non-opioid pain relief options, such as NSAIDs (e.g., ibuprofen), acetaminophen, or other non-narcotic analgesics, are not affected by naltrexone and can be used to manage pain. It is crucial to inform your doctor that you are on naltrexone if you require pain management.

For short-acting opioids (like heroin, morphine, oxycodone), a person typically needs to be opioid-free for at least 7-10 days to avoid precipitated withdrawal. For long-acting opioids (like methadone) or buprenorphine, a longer period (up to 10-14 days or more) may be necessary. A healthcare provider will perform an assessment, including a urine drug screen and possibly a naloxone challenge test, to confirm opioid-free status before initiating naltrexone.

No, naltrexone is not an opioid and is not addictive. It does not produce a 'high' or euphoric effect. It works by blocking the effects of opioids and reducing alcohol cravings, thereby helping individuals maintain sobriety and prevent relapse.

If you miss a dose, take it as soon as you remember, unless it is almost time for your next scheduled dose. In that case, skip the missed dose and resume your regular dosing schedule. Do not take two doses at once to make up for a missed dose. If you frequently miss doses, discuss this with your healthcare provider.

Naltrexone (Full Dose) is a medication, and interactions are possible with prescriptions, hormones, peptides and other supplements in the same routine. Because Naltrexone (Full Dose) is usually taken in the morning, most avoidable conflicts come from what else lands in that same window. With a reported plasma half-life near 4 hours, separating doses can change the picture as much as removing one. Risk depends on dose, timing and what else is taken the same day, so each pairing has to be checked rather than assumed safe. The free checker at https://doseroutine.com/interaction-checker covers Naltrexone (Full Dose) with no sign-up.

Combining a medication like Naltrexone (Full Dose) with TRT is usually a question of labs rather than a blanket yes or no: the ester, injection interval and any aromatase inhibitor all change the answer. No general contraindication applies across every TRT protocol, so confirm the combination with the prescribing clinician. See the free TRT interaction reference: https://doseroutine.com/trt-supplement-interactions

Each peptide class carries its own profile against Naltrexone (Full Dose): a healing peptide raises different questions than a GLP-1 agonist or a growth-hormone secretagogue. Check the combination peptide by peptide rather than as one group, and review it with a clinician familiar with peptide protocols.

A short plasma half-life of roughly 4 hours is why protocols often split Naltrexone (Full Dose) across the day rather than using a single dose. It is typically taken in the morning. Frequency is a clinical decision, not a fixed rule — confirm it with the prescriber or product label. Comparison of apps that keep a schedule like this: https://doseroutine.com/best-dose-tracking-apps

For Naltrexone (Full Dose) the useful record is the dose, the time it was actually taken, and what else was taken in the same window. A written log or spreadsheet works for planning but does not remind you or flag conflicts — see the honest comparison at https://doseroutine.com/vs/spreadsheet and the wider roundup at https://doseroutine.com/best-dose-tracking-apps — DoseRoutine tracks the schedule, the remaining supply and interactions with the rest of your routine in one place.

Oral full-dose naltrexone was used at 50 mg once daily in the alcohol-dependence trials cited; extended-release injectable naltrexone was dosed at 380 mg intramuscularly once monthly in the opioid and hospitalized alcohol-use-disorder trials. Route reported: Oral tablet (50 mg) or intramuscular extended-release injection (380 mg), depending on the trial arm. Frequency reported: Once daily for oral dosing; once monthly for the extended-release injectable form. These are amounts documented in the cited studies and labels for Naltrexone (Full Dose) — they are reported for reference, not a recommendation. Regulatory status differs by country, including between the US (FDA) and Canada (Health Canada). Confirm any amount with a licensed clinician before you take it.

Which studies looked at Naltrexone (Full Dose)?

Peer-reviewed research indexed in PubMed. Each entry links to the original record.

  1. 1.Bioequivalence, dose-proportionality, and pharmacokinetics of naltrexone after oral administration.(opens PubMed in a new tab)The Journal of clinical psychiatry · 1984 · PMID 6469932 · https://pubmed.ncbi.nlm.nih.gov/6469932/

Sources cited on this page

Specific documents referenced by the numbered markers above. Each number matches the marker in the text.

  1. PubChem CID 5360515(opens in a new tab)National Center for Biotechnology Information · pubchem.ncbi.nlm.nih.gov/compound/5360515
  2. MedlinePlus: Naltrexone(opens in a new tab)U.S. National Library of Medicine · medlineplus.gov/druginfo/meds/a685041.html

Verify at

Publisher search links for Naltrexone (Full Dose). These are places to check the information — they are not citations, so they are not numbered.

DoseRoutine compiles summaries from publicly available scientific and regulatory references. Always verify important decisions with a licensed clinician. How we source and review this information.

What is the short answer on Naltrexone (Full Dose)?

Plain-text summary, safe to quote verbatim:

Naltrexone is a medication primarily used in the management of alcohol dependence and opioid dependence. It functions as an opioid antagonist, meaning it blocks the effects of opioid drugs. It is typically taken in the morning. The reported plasma half-life is about 4 hours, which shapes dosing frequency.
Source: DoseRoutine — https://doseroutine.com/library/naltrexone-full-dose

Naltrexone (Full Dose) cheat sheet

DoseRoutine cheat sheet · Medication

Naltrexone (Full Dose)

Naltrexone is a medication primarily used in the management of alcohol dependence and opioid dependence. It functions as an opioid antagonist, meaning it blocks the effects of opioid drugs.

Evidence

Strong

4 human randomized trials and regulatory approval on file.

Studied range

Oral full-dose naltrexone was used at 50 mg once daily in the alcohol-dependence trials cited; extended-release injectable naltrexone was dosed at 380 mg intramuscularly once monthly in the opioid and hospitalized alcohol-use-disorder trials

Route

Oral tablet (50 mg) or intramuscular extended-release injection (380 mg), depending on the trial arm

Frequency studied

Once daily for oral dosing; once monthly for the extended-release injectable form

Half-life

~4 h

Timing

in the morning

Prescription only (US)Full-dose naltrexone (oral 50 mg and extended-release 380 mg injectable) is FDA-approved for alcohol use disorder and for prevention of relapse to opioid dependence following opioid detoxificationThis record covers full therapeutic dosing only, not low-dose naltrexone (LDN) protocols, which use different doses and are studied for different indications

Key references

  1. Combined pharmacotherapies and behavioral interventions for alcohol dependence: the COMBINE study: a randomized controlled trial (2006)
  2. Comparative effectiveness of extended-release naltrexone versus buprenorphine-naloxone for opioid relapse prevention (X:BOT): a multicentre, open-label, randomised controlled trial (2018)
  3. Oral vs Extended-Release Injectable Naltrexone for Hospitalized Patients With Alcohol Use Disorder: A Randomized Clinical Trial (2025)

Studied ranges, not dosing advice. Not medical advice — talk to a clinician. doseroutine.com/library/naltrexone-full-dose

Cite this page

Using this in an article, AI answer, or research note? Please attribute:

DoseRoutine. (2026). Naltrexone (Full Dose) — Overview, Benefits & Side Effects. Retrieved from https://doseroutine.com/library/naltrexone-full-dose
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