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Naltrexone

Naltrexone is a medication used to treat alcohol dependence and opioid dependence, available as an oral tablet and an extended-release injectable suspension.

Brand names ReViaVivitrol
Drug class Opioid Antagonist
Rx Forms 2
Dr. Brian Staiger, PharmD, BCPS
Reviewed by Last reviewed Jul 10, 2026 Content updated Oct 2, 2026
🧬 Where this information comes from Click to expand

The clinical label records used on this page are FDA-filed Structured Product Labeling (SPL) retrieved through openFDA. We identified 46 clinical label sets within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. Forms, routes, brands, labelers, strengths, and NDC product-record counts are built separately from matching FDA National Drug Code Directory records. The linked DailyMed document is a representative official source for verification, not the page’s only clinical source. View the linked label on DailyMed →

✓No current FDA shortage listed · checked Oct 7, 2026
Naltrexone at a glance The quick version — the full detail is in the Patient Information Guide below.
Dr. Brian Staiger, PharmD, BCPS
The Pharmacist’s Take By · Clinical pharmacist · Written

Naltrexone is a long-standing medicine for alcohol dependence and opioid dependence, used alongside counseling, that blocks the brain’s opioid receptors without switching them on, so opioids lose their effect and alcohol feels less rewarding; it has been around since the mid-1980s, is available generically and causes no high. Most people tolerate it fairly well, with nausea, headache, dizziness or poor sleep the usual complaints, plus a sore spot after the monthly Vivitrol shot. The real danger is opioid overdose, because naltrexone lowers opioid tolerance, so a once-normal opioid dose can be life-threatening during treatment, after a missed dose or after stopping.

Clinical pearls

  • Be opioid-free 7 to 10 days before starting, longer after buprenorphine or methadone, or sudden severe withdrawal can follow.
  • It blocks opioid pain relievers and opioid-containing cough and antidiarrheal products, so tell every prescriber, dentist and surgeon.
  • Ask for naloxone to keep at home, and make sure family know where it is and how to use it.
  • Yellow skin or eyes, dark urine or severe stomach pain can signal liver injury, so call your doctor promptly.
How we write & review this content — our editorial policy →
How you get itPrescription only
Comes asTablet, Injection
Earliest FDA record1984
Companies listing it with the FDA23
FDA label last updatedMay 21, 2026
FDA’s strongest warning (boxed)None on the label

Patient information guide A plain-language walkthrough of Naltrexone, written from its FDA label.

What Naltrexone is used for

▾

Naltrexone is used to treat alcohol dependence and opioid dependence. The specific approved uses vary by product and form:

  • Naltrexone Hydrochloride tablets are approved to treat alcohol dependence and to block the effects of externally administered opioids in people being treated for opioid dependence.
  • Vivitrol (extended-release injectable suspension) is approved to treat alcohol dependence in patients who are able to stop drinking before starting treatment, and to prevent relapse to opioid dependence following opioid detoxification.
  • The extended-release injectable suspension (generic kit form) carries the same indications as Vivitrol: alcohol dependence and prevention of relapse to opioid dependence after detoxification.
  • All naltrexone products are intended as one part of a broader treatment plan that includes counseling and psychosocial support — naltrexone alone is not a complete treatment for addiction.

How Naltrexone works

▾

Naltrexone is an opioid antagonist — it binds tightly to opioid receptors in the brain, especially the mu opioid receptor, without activating them. By occupying those receptors, it blocks opioids like heroin or prescription pain medicines from producing their usual effects. In alcohol dependence, the exact mechanism isn't fully understood, but naltrexone is thought to interrupt the brain's natural opioid reward pathways that alcohol activates, reducing the urge to drink. Importantly, naltrexone does not cause dependence or tolerance — stopping it does not cause withdrawal.

The blockade of opioids is competitive, meaning that very large doses of opioids could potentially overcome it. Trying to push through the blockade by taking large amounts of opioids is extremely dangerous and can cause life-threatening overdose.

Naltrexone dosage

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Naltrexone comes in two forms with different dosing schedules. Naltrexone Hydrochloride tablets are taken by mouth once daily — food is not required, but follow your prescriber's guidance. The extended-release injectable suspension (Vivitrol) is given once every four weeks or once a month as a deep injection into the buttock muscle, alternating sides each time; it must always be given by a healthcare provider.

  • Patients must be opioid-free for at least 7–10 days before starting either form to avoid sudden, severe withdrawal; those switching from buprenorphine or methadone may need up to two weeks.
  • If you miss a Vivitrol injection, contact your healthcare provider to receive it as soon as possible.
  • Do not adjust your dose or stop taking naltrexone without talking to your prescriber first.

Dosing details from the FDA-approved label

From the Naltrexone prescribing information (“Dosage and Administration”). Doses are set by your prescriber for your product, condition, kidney function and age — never change a dose on your own.

  • Treatment of Alcoholism (naltrexone hydrochloride tablets)
    • A dose of 50 mg once daily is recommended for most patients
    • The placebo-controlled studies used 50 mg once daily for up to 12 weeks
    • Opioid-free (including tramadol) before starting; an opioid-free interval of a minimum of 7 to 10 days is recommended for patients previously dependent on short-acting opioids.
  • Treatment of Opioid Dependence (naltrexone hydrochloride tablets)
    • Initial dose of 25 mg
    • If no withdrawal signs occur, the patient may be started on 50 mg a day thereafter
    • Patients transitioning from buprenorphine or methadone may be vulnerable to precipitated withdrawal for as long as 2 weeks.
  • Alternative Dosing Schedules (supervised administration, naltrexone hydrochloride tablets)
    • 50 mg every weekday with a 100 mg dose on Saturday, 100 mg every other day, or 150 mg every third day
    • Blockade may be reduced by extended dosing intervals; there may be a higher risk of hepatocellular injury with single doses above 50 mg.
  • Naloxone Challenge Test, intravenous
    • Inject 0.2 mg naloxone and observe for 30 seconds for signs or symptoms of withdrawal
    • If no evidence of withdrawal, inject 0.6 mg of naloxone and observe for an additional 20 minutes
    • Some patients may respond to lower doses; in some cases 0.1 mg IV naloxone has produced a diagnostic response.
  • Naloxone Challenge Test, subcutaneous
    • Administer 0.8 mg naloxone
    • Observe for 20 minutes for signs or symptoms of withdrawal
    • Repeat the challenge in 24 hours if positive or in doubt.
  • VIVITROL (naltrexone extended-release injectable suspension)
    • 380 mg delivered intramuscularly (deep) as a gluteal injection every 4 weeks or once a month, alternating buttocks for each subsequent injection
    • Opioid-free duration of a minimum of 7–10 days recommended; must be prepared and administered by a healthcare provider; needle length (1 1/2 or 2 inches) chosen by body habitus.
Read the label’s full dosing text

DOSAGE AND ADMINISTRATION To reduce the risk of precipitated withdrawal in patients dependent on opioids, or exacerbation of a preexisting subclinical withdrawal syndrome, opioid-dependent patients, including those being treated for alcohol dependence, should be opioid-free (including tramadol) before starting naltrexone hydrochloride tablets treatment. An opioid-free interval of a minimum of 7 to 10 days is recommended for patients previously dependent on short-acting opioids. Patient Access to an Opioid Overdose Reversal Agent for the Emergency Treatment of Opioid Overdose When initiating and renewing treatment with naltrexone hydrochloride tablets, USP, inform patients and caregivers about opioid overdose reversal agents (e.g., naloxone, nalmefene) and discuss the importance of having access to an opioid overdose reversal agent. Because patients being treated for opioid use disorder have the potential for relapse, putting them at risk for opioid overdose after naltrexone hydrochloride tablets, USP treatment is discontinued, or after a dose of naltrexone hydrochloride tablets, USP is missed, strongly consider recommending or prescribing an overdose reversal agent naloxone for the emergency treatment of opioid overdose (see WARNINGS ). Discuss the options for obtaining an opioid overdose reversal agent (e.g., prescription, over-the-counter (some products), or as part of a community-based program) (see WARNINGS ) . There are important differences among the opioid overdose reversal agents, such as route of administration, product strength, approved patient age range, and pharmacokinetics. Be familiar with these differences, as outlined in the approved labeling for those products, prior to recommending or prescribing such an agent. Switching from Buprenorphine, Buprenorphine/Naloxone, or Methadone There are no systematically collected data that specifically address the switch from buprenorphine or methadone to naltrexone hydrochloride tablets; however, review of postmarketing case reports have indicated that some patients may experience severe manifestations of precipitated withdrawal when being switched from opioid agonist therapy to opioid antagonist therapy (see WARNINGS ). Patients transitioning from buprenorphine or methadone may be vulnerable to precipitation of withdrawal symptoms for as long as 2 weeks.

Excerpted — the section continues on the label. Read the full Dosage and Administration section on DailyMed →

Naltrexone side effects

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The most common side effects reported with naltrexone include:

Common side effects

  • Nausea or vomiting
  • Diarrhea or stomach pain
  • Headache
  • Dizziness or fainting
  • Trouble sleeping (insomnia)
  • Fatigue or low energy
  • Decreased appetite
  • Injection site pain, swelling, or tenderness (with the injectable form)
  • Anxiety or depression
  • Injection site reactions — pain, tenderness, swelling, hardness, itching, or bruising (with the injectable form)

When to get medical help

  • Call 911 or get emergency help immediately if you use opioids after stopping naltrexone — your tolerance is reduced and even a small amount can cause life-threatening overdose
  • Call your doctor right away if you have symptoms of liver problems: yellowing of skin or eyes, dark urine, severe stomach pain, or unusual fatigue
  • Seek medical attention if you experience signs of a severe allergic reaction: hives, swelling of the face or throat, or trouble breathing
  • Tell your doctor immediately if you develop new or worsening depression, thoughts of suicide, or unusual mood changes
  • For the injectable form, contact your doctor if you notice an injection site that is very painful, increasingly swollen, hard, or shows signs of infection — some reactions have required surgery
  • Seek emergency care if you develop shortness of breath and low oxygen levels (possible eosinophilic pneumonia, a rare lung reaction)

Serious reactions to act on immediately include signs of liver damage (yellowing skin or eyes, dark urine, severe stomach pain), severe injection site reactions (growing swelling, abscess, or open wound), allergic reactions (hives, throat swelling, trouble breathing), shortness of breath and low oxygen, or new or worsening depression and thoughts of self-harm.

Naltrexone warnings and precautions

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  • Opioid overdose risk: Naltrexone reduces your tolerance to opioids. If you use opioids while on treatment, after a missed dose, or after stopping treatment entirely, a dose that used to feel normal can now cause life-threatening overdose. Fatal overdoses have been reported. Make sure family members know about this risk, and ask your doctor about keeping an overdose reversal medicine (like naloxone) on hand.
  • Precipitated withdrawal: Starting naltrexone too soon after opioid use can trigger sudden, severe withdrawal — including confusion, hallucinations, severe vomiting, and diarrhea — serious enough to require hospitalization or intensive care. You must be fully opioid-free before starting.
  • Liver injury: Cases of hepatitis and significant liver damage have been linked to naltrexone. Tell your doctor right away if you notice yellowing of the skin or eyes, dark urine, or unusual stomach pain.
  • Depression and suicidality: Depression and suicidal thoughts have been reported. Patients, families, and caregivers should watch closely for changes in mood and report them to the healthcare provider promptly.
  • Injection site reactions (injectable form): Some reactions at the injection site have been severe, including tissue death requiring surgery. Report any increasing pain, swelling, or signs of infection at the injection site to your doctor.

Naltrexone interactions

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Naltrexone can interact with several types of medicines. Talk to your doctor or pharmacist about everything you take before starting naltrexone:

  • Opioid-containing medicines (prescription pain relievers, some cough medicines, antidiarrheal drugs like loperamide in high doses) — naltrexone blocks their effects, so they won't work as expected. In an emergency requiring opioid pain relief, higher doses may be needed, but this increases the risk of serious breathing problems.
  • Disulfiram (Antabuse) — both drugs can stress the liver; using them together is generally not recommended unless the benefit clearly outweighs the risk.
  • Thioridazine (an older antipsychotic) — taking both together has been associated with unusual drowsiness and sedation.

Interactions listed in the FDA-approved label

From the Naltrexone prescribing information (“Drug Interactions”): what the manufacturer studied or reported to the FDA.

  • Disulfiram: The safety and efficacy of concomitant use with naltrexone hydrochloride is unknown, and use of two potentially hepatotoxic medications is not ordinarily recommended. Not ordinarily recommended unless the probable benefits outweigh the known risks.
  • Thioridazine: Lethargy and somnolence have been reported following doses of naltrexone hydrochloride and thioridazine.
  • Opioid-containing medicines (cough and cold preparations, antidiarrheal preparations, opioid analgesics): Patients taking naltrexone hydrochloride may not benefit from opioid-containing medicines. In an emergency when opioid analgesia must be given, the amount of opioid required may be greater than usual, and the resulting respiratory depression may be deeper and more prolonged.
  • Drugs other than opiates (general): Studies to evaluate possible interactions between naltrexone hydrochloride and drugs other than opiates have not been performed. Caution is advised if concomitant administration of naltrexone hydrochloride and other drugs is required.
Read the label’s full interactions text

Drug Interactions Studies to evaluate possible interactions between naltrexone hydrochloride and drugs other than opiates have not been performed. Consequently, caution is advised if the concomitant administration of naltrexone hydrochloride and other drugs is required. The safety and efficacy of concomitant use of naltrexone hydrochloride and disulfiram is unknown, and the concomitant use of two potentially hepatotoxic medications is not ordinarily recommended unless the probable benefits outweigh the known risks. Lethargy and somnolence have been reported following doses of naltrexone hydrochloride and thioridazine. Patients taking naltrexone hydrochloride may not benefit from opioid containing medicines, such as cough and cold preparations, antidiarrheal preparations, and opioid analgesics. In an emergency situation when opioid analgesia must be administered to a patient receiving naltrexone hydrochloride, the amount of opioid required may be greater than usual, and the resulting respiratory depression may be deeper and more prolonged (see PRECAUTIONS ).

Read the full Drug Interactions section on DailyMed →

Not a complete list. The label covers the interactions the manufacturer studied or reported, and our own interaction database does not cover every medicine either. Bring your full medication list, including vitamins and herbal products, to your pharmacist.

🌿56 supplements and herbs with documented Naltrexone interactions, ranked by severity Check Naltrexone against a supplement or herb →

Before taking Naltrexone

▾
  • Do not take naltrexone if you are currently using opioid medicines or are physically dependent on opioids — it will trigger severe, sudden withdrawal.
  • Do not take it if you are in acute opioid withdrawal or have recently tested positive for opioids on a urine screen.
  • Do not take it if you have had a severe allergic reaction to naltrexone or any component of the injectable formulation (including PLG or carboxymethylcellulose).
  • Tell your doctor about any liver disease — naltrexone has been linked to liver injury, and severe liver impairment has not been well studied.
  • Tell your doctor about kidney disease — use with caution in moderate to severe kidney impairment, since naltrexone and its breakdown products are cleared mainly through the kidneys.
  • If you are pregnant or trying to become pregnant, discuss the risks carefully with your doctor — animal studies showed increased early pregnancy loss at high doses, though the risks of untreated addiction must also be weighed.
  • Naltrexone passes into breast milk — talk to your doctor about whether to breastfeed while taking it.
  • Safety and effectiveness have not been established in children.
  • Older adults are more likely to have reduced kidney function and may need closer monitoring.

Naltrexone overdose

▾

There is limited experience with naltrexone overdose in people. In a clinical study, subjects who took very high daily doses for up to a week showed no signs of toxicity. If an overdose is suspected, the prescribing guidance recommends treating symptoms in a closely supervised medical setting. Contact a poison control center for the most current guidance.

What Naltrexone does in the body

▾

Naltrexone is a pure opioid antagonist — it blocks opioid receptors without activating them, reversibly preventing opioids from producing their effects. In people physically dependent on opioids, naltrexone will trigger withdrawal symptoms if started too soon. It does not cause tolerance or physical dependence, and stopping it does not produce withdrawal. For alcohol, naltrexone has been shown to reduce alcohol consumption in clinical studies, though the exact mechanism is not fully understood — the endogenous (natural) opioid system appears to be involved.

How your body processes Naltrexone

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When taken by mouth, naltrexone is rapidly and nearly completely absorbed from the gut, but a significant portion is broken down by the liver on first pass, so the amount that reaches the bloodstream varies. It is converted mainly to a metabolite called 6-β-naltrexol, which also has activity; both are cleared primarily through the kidneys. The oral tablet form reaches peak blood levels within about one hour. The extended-release injectable suspension, by contrast, produces a sustained release profile over a full month — with an initial small peak around two hours after injection, a second peak two to three days later, and measurable levels for more than a month, providing much longer-lasting coverage than the daily tablet.

How to store Naltrexone

▾

Store at 20° to 25°C (68° to 77°F) . Dispense in a tight, light-resistant container as defined in the USP, with a child-resistant closure (as required). Protect from light.

Written from the FDA-approved label with AI and reviewed by our pharmacy team. How we use AI →

56

Supplements & herbs that interact with Naltrexone

56 supplements and herbal products have documented interactions with Naltrexone in the licensed clinical database we use. Most are manageable — but your pharmacist should know about everything you take, including vitamins and herbals.

Severity mix
  • Major · 4
  • Moderate · 43
  • Minor · 9
ACTIVATED CHARCOAL Major BEER Major SIBERIAN COCKLEBUR Major WINE Major ASHWAGANDHA Moderate BLACK COHOSH Moderate BOLDO Moderate BUCHU Moderate +48 more
Every supplement checked against Naltrexone — ranked by severity The full interaction hub: 4 major · 43 moderate · 9 minor · every one linked to its full report. Check Naltrexone against your exact supplements

Educational information from a licensed clinical database (Natural Medicines) — see our data sources & update cadence. Not medical advice: an interaction being documented does not mean it will happen to you; do not start or stop medications or supplements without professional guidance.

Naltrexone: pharmacist answers to common questions

Quick, plain-English answers to the questions patients ask most about Naltrexone — the kind of thing our pharmacy team would talk through with you at the counter.

What exactly does naltrexone do — does it stop cravings or just block the high?

▾
Good question. Naltrexone works mainly by blocking opioid receptors in the brain, so if you use an opioid while taking it, you won't get the usual effect. For alcohol, it seems to dampen the rewarding feeling alcohol produces, which can reduce cravings for some people. It's not a craving cure on its own, but as part of a counseling program, many people find it really helps. It won't make you feel high or sedated — it has no opioid activity of its own.

I'm worried about starting this — what happens if I accidentally take an opioid pain pill while on naltrexone?

▾
The opioid won't work the way it normally would — the pain relief will be blocked. That said, in a true medical emergency where you absolutely need opioid pain relief, a higher dose can sometimes overcome the blockade, but that also raises the risk of serious breathing problems. Always make sure any doctor or dentist treating you knows you're on naltrexone. Carry information about it with you in case of an emergency.

Is it safe to stop naltrexone suddenly, and what happens when I do?

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Stopping naltrexone itself does not cause withdrawal — it isn't physically addictive. But here's the really important part: when you stop, your tolerance to opioids drops. If you were being treated for opioid dependence and you relapse after stopping, even a smaller amount of opioids than you used before could cause a life-threatening overdose. Please talk to your prescriber before stopping, and make sure people close to you know about this risk.

My friend told me I have to be off opioids before I start — how long exactly, and why?

▾
Yes, this is one of the most important rules with naltrexone. You need to be completely opioid-free for at least 7 to 10 days if you've been using short-acting opioids. If you've been on buprenorphine or methadone, you may need up to two weeks. Starting too soon causes something called precipitated withdrawal — a sudden, very intense withdrawal that can be severe enough to land you in the hospital. Your doctor may do a urine test or a naloxone challenge test to make sure it's safe to start.

What side effects should I actually expect, and which ones mean I should call someone right away?

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The most common ones are nausea, headache, tiredness, trouble sleeping, and stomach upset — most people find these manageable and they often improve with time. If you get the injection, expect some soreness or swelling at the injection site. What you should call your doctor about right away: yellowing skin or eyes, very dark urine, or bad stomach pain (signs of liver problems); an injection site that keeps growing, gets warm, or looks infected; shortness of breath; or any new feelings of depression or thoughts of self-harm.

Can I drink alcohol while taking naltrexone for opioid dependence?

▾
Naltrexone won't make you violently sick if you drink — it's not like disulfiram (Antabuse), which causes a harsh reaction to alcohol. But alcohol use is still a serious concern, especially during addiction recovery. Your treatment program and your prescriber are your best guides here. Be honest with your care team about any alcohol use so they can help you get the best outcome.

Is Naltrexone available over the counter?

▾
No. Naltrexone is a prescription medicine: every Naltrexone product listed with the FDA is prescription only, so it is not sold over the counter. Your prescriber decides whether it is appropriate for you, and your pharmacist dispenses it.

When was Naltrexone first available?

▾
The earliest FDA record we hold for Naltrexone is from 1984: its first approval in Drugs@FDA or its earliest product listing in the NDC Directory, whichever is older. Many older medicines were in use before their first formal FDA approval, so this is the earliest date on record, not necessarily when Naltrexone was first used.

Who makes Naltrexone?

▾
23 companies currently list Naltrexone products in the FDA's NDC Directory, including Bryant Ranch Prepack, Aphena Pharma Solutions - Tennessee, LLC, A-S Medication Solutions. That count includes repackagers and distributors as well as manufacturers (companies that sell only the raw ingredient are not counted), so fewer companies actually make it; the label on your bottle names the one that supplied yours.

Answers drafted from the FDA-approved label with AI and reviewed by our pharmacy team. How we use AI →

More about Naltrexone on HelloPharmacist

📊Naltrexone supplement interactions56 checked — ranked by severity 🌿Drug & Supplement CheckerNaltrexone vs. vitamins & herbs 💬Ask a PharmacistFree answer, usually < 24h 🔎NDC & pricing lookupFind Naltrexone NDCs & costs 🅰️Browse Drugs A–ZLook up any medication
Detailed data & references for Naltrexone Forms & strengths, pricing, billing codes, manufacturers, safety reports and sourcing — the data behind the page. Most people can stop here. Each section below opens on a tap.

Naltrexone forms and strengths (how it comes)

Naltrexone is available in 2 forms. Different forms and brands can have different approved uses, doses, schedules, and directions. Follow the instructions for your exact product, and do not switch forms without guidance from your prescriber or pharmacist.

Need a version that does not list lactose, a gluten source, a dye or gelatin? Inactive ingredients differ by manufacturer: see Naltrexone inactive ingredients by manufacturer.

Tablet

By mouth
How this form is used
What it may be used for
  • Naltrexone Hydrochloride tablets are used to treat alcohol dependence
  • Naltrexone Hydrochloride tablets are used to block the effects of opioids in people being treated for opioid dependence
Important instructions
  • Naltrexone Hydrochloride tablets are taken by mouth once daily
  • Patients must be opioid-free for at least 7–10 days before starting Naltrexone Hydrochloride tablets to avoid triggering sudden withdrawal
  • Follow your prescriber's instructions on dosing schedule and duration of treatment
Available strengths 1 strength
50 mg
75 FDA-listed product records ⓘ

Injection

By injection
How this form is used
What it may be used for
  • Vivitrol (extended-release injectable suspension) is used to treat alcohol dependence in patients who are not actively drinking before starting treatment
  • Vivitrol is used to prevent relapse to opioid dependence after opioid detoxification
  • The extended-release injectable suspension must always be part of a comprehensive treatment program including psychosocial support
Important instructions
  • Vivitrol must be prepared and administered by a healthcare provider as a deep intramuscular injection into the gluteal muscle (buttock)
  • Vivitrol is given once every four weeks or once a month, alternating buttocks with each injection
  • Patients must be opioid-free for at least 7–10 days before starting Vivitrol to avoid precipitating severe withdrawal
  • If a dose of Vivitrol is missed, contact your healthcare provider to receive the next injection as soon as possible
Available strengths 1 strength
380 mg/4 mL
1 FDA-listed product record ⓘ

Naltrexone on the U.S. market: products, makers and brands

How Naltrexone appears in the FDA’s National Drug Code Directory — including its dosage forms, strengths, brand names, manufacturers, and FDA-listed product records. These are directory records, not sales or prescription volume.

23 companies list 48 Naltrexone product records with the FDA, mostly as tablet, injection; the earliest marketing or approval year on record is 1984. Brand names on the directory include ReVia, Vivitrol; the rest are generics.

2
Dose forms ⓘ
23
Labelers (makers, repackagers, distributors)
3
Brand names
48
FDA-listed product records ⓘ
1984
Earliest FDA record ⓘ

FDA-listed product records by dose form (tablet variants merged) — FDA National Drug Code Directory. Record counts are not sales or prescription volume.

Also listed with the FDA, not a patient dose form: Powder (71) · Kit (7) — bulk drug substance sold to compounders/manufacturers and multi-item kits. These aren’t counted in the dose-form total above.

Bryant Ranch Prepack38%
Aphena Pharma Solutions - Tennessee, LLC8%
A-S Medication Solutions4%
Alkermes, Inc.4%
Coupler LLC4%
Precision Dose Inc.4%
Other makers38%

Share of FDA-listed product records by manufacturer — FDA National Drug Code Directory. Record counts are not sales or prescription volume.

How widely Naltrexone is used (Medicaid data)

A general measure of how commonly Naltrexone is prescribed, based on Medicaid — one of the largest public drug programs. The figure below is prescriptions filled in Q1–Q4 2025, summed across every form and brand of the drug.

Think of this as a proxy for how widely Naltrexone is used, drawn from freely available public data. Medicaid is just one program — these numbers don’t include Medicare, other government coverage, or commercial and cash-pay prescriptions, so real-world use is higher than what’s shown here.

1,052,053
Medicaid prescriptions filled (Q1–Q4 2025)
$395.7M gross Medicaid reimbursement (before mandatory rebates — net cost is lower)

How commonly is Naltrexone prescribed? Of the 1,601 medications we measure, Naltrexone ranks #171 by Medicaid prescriptions — more than 89% of them.

Where Naltrexone ranks among the drugs we measure · Q1–Q4 2025 · neighbors ±5
Total prescriptions — #171 of 1,601
#166 Cyanocobalamin 1,095,564 Rx #167 Clobetasol Topical 1,093,267 Rx #168 Cyanocobalamin Injecti... 1,087,734 Rx #169 Nifedipine 1,079,242 Rx #170 Cariprazine 1,076,596 Rx #171 Naltrexone 1,052,053 Rx #172 Lurasidone 1,049,340 Rx #173 Paliperidone 1,015,111 Rx #174 Levocetirizine 1,014,061 Rx #175 Ethinyl Estradiol / Fe... 1,010,948 Rx #176 Clotrimazole Topical 1,007,055 Rx

Utilization by Naltrexone product

Pick a product to see its own Medicaid numbers. Each chip is one clinical product — a specific strength & dosage form as defined by RxNorm — with brand-name and generic versions combined.

The 50 mg oral tablet is the most-dispensed Naltrexone product — about 78% of these Medicaid prescriptions.

naltrexone hydrochloride 50 MG Oral Tablet Most dispensed

817,574 Medicaid prescriptions (Q1–Q4 2025) 78% of Naltrexone prescriptions shown $33.6M gross reimbursement (before rebates) ≈ $41 per prescription (gross)

Summed across the 18 of 101 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 1483744

naltrexone 380 MG Injection

234,479 Medicaid prescriptions (Q1–Q4 2025) 22% of Naltrexone prescriptions shown $362.1M gross reimbursement (before rebates) ≈ $1,544 per prescription (gross)

Summed across the 1 of 6 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 637213

Shares are of the Medicaid prescriptions shown here. Product grouping follows RxNorm (the National Library of Medicine’s drug terminology), so “one product” means one strength & dosage form regardless of manufacturer. Dollar figures are gross Medicaid reimbursement before mandatory rebates — rebates (often large, especially for brand-name drugs) are confidential, so actual net cost to Medicaid is lower than shown.

Source: Medicaid State Drug Utilization Data (CMS), aggregated by generic ingredient — summed across every NDC (all brands, strengths, salt forms and dosage forms) of Naltrexone, and across all states and both fee-for-service and managed-care claims. A general popularity signal; it excludes Medicare, commercial insurance and cash prescriptions, so it is not total U.S. use. Based on the 19 of 107 listed Naltrexone NDCs with Medicaid activity.

Compare Naltrexone products

A representative set of FDA-listed product records for Naltrexone — across manufacturers, strengths, and dosage forms, grouped by form with each product’s manufacturer and how the FDA approved it. The same medicine may be made and packaged by different companies, so a single drug can have many directory entries. (It’s also why a refill can look different — a new shape, color, or box — even though it contains the same medication.)

Showing 48 of 48 products — FDA National Drug Code Directory. See every product, package size and price: browse all 48 Naltrexone NDCs →

Naltrexone side effects reported to the FDA (FAERS)

After a medicine reaches the market, patients, doctors and drugmakers can send the FDA reports of problems they think may be linked to it. Here’s what’s been reported for Naltrexone — a signal of what to watch for, not proof the drug caused it.

The effects most often named in FDA reports that mention Naltrexone are injection site reaction, nausea, injection site pain; about 31% of the reports were classed as serious. These are voluntary reports, so they show what people report, not how often it happens.

40,504
Reports mentioning it
31%
Reported as serious
12
Distinct effects shown
Most reported effects
Injection Site Reaction
4,417
Nausea
4,208
Injection Site Pain
3,192
Headache
2,685
Fatigue
2,479
Dizziness
2,116
Feeling Abnormal
2,032
Alcoholism
1,959
Injection Site Mass
1,931
Pain
1,860
Age groups
Adult · 11,047Elderly · 438Adolescent · 67Child · 19Infant · 11Neonate · 4

Source: openFDA, from the FDA Adverse Event Reporting System (FAERS). These are voluntary reports — they don’t prove the drug caused the effect, and counts reflect how often something was reported, not how often it actually happens. Reports also often name the very problem the medicine is taken for — a common reason to file one is that the drug didn’t help — so for a pain reliever you may see “pain” high on the list; that points to why the report was filed, not to the drug causing the symptom. This counts every report that lists Naltrexone in any role, so the total runs higher than the FDA’s official dashboard, which counts only cases where the drug is the suspect. For the authoritative figures, see the FDA FAERS Public Dashboard. Always talk to your pharmacist or doctor.

Naltrexone FDA approval history

How Naltrexone went from FDA review to the pharmacy shelf — the key milestones in its regulatory journey.

Naltrexone was first approved by the FDA in 1984 (Brand: REVIA · Teva Womens); the first generic version was approved in 1998. It remains available in U.S. pharmacies today.

1984
Brand approved
Brand: REVIA · Teva Womens
1998
First generic approved
Lower-cost ANDA competition begins
2026
Available today
Active in U.S. pharmacies

Source: Drugs@FDA.

Naltrexone recall history

A recall is when a specific batch of a medicine is pulled from the market — usually a manufacturing issue, not a problem with the drug itself. Class I is most serious, Class III least.

The FDA’s enforcement reports list one Naltrexone recall since July 2021. It is no longer listed as ongoing. A recall names specific lots from one company, so check the lot number on your own bottle rather than assuming every product is affected; your pharmacist can check whether your supply came from an affected lot.

Class II Apr 13, 2022 · Terminated · Mckesson Medical-Surgical Inc. Corporate Office
cGMP deviations: Temperature abuse
  • Naltrexone Hydrochloride Tablets, USP, 50 mg, 100-count bottle, Rx only, MFG: Mallinckrodt Inc., NDC 0406-1170-03 Lots: McKesson Medical-Surgical (MMS) is not able to identify the particular lot number received by a particular consignee for the recalled prescription products. Each letter includes the date it was distributed to customers and the dates that i… FDA record D-1039-2022 →

Source: FDA enforcement (recall) reports, via openFDA; our copy was last updated Sep 24, 2026.

RxNorm Concept Web — From Ingredient to Every Form and Strength

This page starts with one ingredient concept (IN). The branches below show its dose-form concepts (SCDF), then the available clinical drug and strength concepts (SCD). Combination products remain separate concepts with their own pages.

Ingredient (IN) Naltrexone RxCUI 7243 2 dose forms · 4 strengths
  1. Dose form (SCDF) Injection RxCUI 1740871 In current FDA listings
    Clinical drug / strength (SCD) 380 MG RxCUI 637213
  2. Dose form (SCDF) Oral Tablet RxCUI 372990 In current FDA listings
    Clinical drug / strength (SCD) hydrochloride 100 MG RxCUI 1483774 hydrochloride 25 MG RxCUI 1483780 hydrochloride 50 MG RxCUI 1483744

Look up RxCUI 7243 in the RxCUI Atlas →

RxNorm is the U.S. National Library of Medicine’s normalized drug vocabulary. Its concept hierarchy can include forms that are not currently marketed; the status on each branch compares that concept with current FDA listings. RxCUIs identify vocabulary concepts, not individual packages or manufacturers.

💵 What Naltrexone costs pharmacies (NADAC benchmark)

The national average invoice price pharmacies pay for the drug itself, from CMS's NADAC survey (data as of Sep 30, 2026). This is a supply-cost benchmark — not a retail price and not what you'd pay at the counter.

FormStrengthPharmacy acquisition benchmark
Tablet, Film Coated · Oral 50 mg $1.14 per tablet NDC details & price history
Why show this? Your out-of-pocket cost depends on insurance, pharmacy markup, and discounts — but the acquisition benchmark tells you whether the medication itself is inexpensive or costly, which strengths cost more per dose, and whether a cash-price quote is in a reasonable range. Each row links to the NDC-level record with its full price history.

Source: CMS National Average Drug Acquisition Cost (NADAC), a survey of retail pharmacy invoice prices. Benchmarks shown are the range across package sizes of a representative product for each form and strength — other manufacturers' products may differ.

Naltrexone brand names

Naltrexone is sold under 2 brand names in the FDA directory — ReVia, Vivitrol. A brand and its generic contain the same active ingredient; the brand name belongs to one company's product.

ReVia Vivitrol

Who makes Naltrexone: manufacturers and labelers

23 companies list Naltrexone products with the FDA. By number of product records, the largest are Bryant Ranch Prepack, Aphena Pharma Solutions - Tennessee, LLC, A-S Medication Solutions. Labelers include manufacturers and repackagers; the product in your bottle depends on which one your pharmacy stocks.

Bryant Ranch Prepack 18 Aphena Pharma Solutions - Tennessee, LLC 4 A-S Medication Solutions 2 Alkermes, Inc. 2 Coupler LLC 2 Precision Dose Inc. 2 Remedyrepack Inc. 2 Accord Healthcare, Inc. 1 American Health Packaging 1 Amneal Pharmaceuticals NY LLC 1 AvKARE 1 Chartwell RX, LLC 1 Elite Laboratories, Inc. 1 Golden State Medical Supply, Inc. 1 Heritage Pharmaceuticals Inc d/b/a Avet Pharmaceuticals Inc 1 Major Pharmaceuticals 1 NCS HealthCare of KY, LLC dba Vangard Labs 1 NuCare Pharmaceuticals Inc. 1 Proficient Rx LP 1 Redpharm Drug 1 SpecGx LLC 1 Sun Pharmaceutical Industries, Inc. 1 TAGI Pharma Inc. 1

Naltrexone drug class (RxNorm)

Naltrexone belongs to the Opioid Antagonist class.

Pharmacologic class Opioid Antagonist
Drug family (ATC) Centrally acting antiobesity products, Natural opium alkaloids, Drugs used in alcohol dependence
How it works Opioid Antagonists

Classified by RxNorm RxClass — the U.S. National Library of Medicine's standardized drug-classification service (Established Pharmacologic Class from the FDA, the ATC drug family from the WHO, and mechanism of action). Reference only, not medical advice.

Sources for this Naltrexone page

Core label, product, RxNorm, safety, and utilization data on this page come from the sources identified below. AI-written, editorial, and licensed sections are labeled separately.

📄
FDA-filed drug labels (SPL) Uses, dosing, warnings & side effects from SPL records retrieved through openFDA; the linked representative set can be verified on DailyMed. ✓ Linked label effective May 21, 2026
🏭
Forms, brands & labelersAggregated from ingredient-matched FDA National Drug Code Directory product records for Naltrexone.
📈
Real-world reportsThe FDA Adverse Event Reporting System (FAERS), served through openFDA.
🚨
Recalls & shortagesopenFDA drug-enforcement reports and the FDA drug-shortage database.
🧾 Clinical label set — FDA-filed SPL labels retained for Naltrexone after exact ingredient or ingredient-combination matching and applicable route/form matching
Clinical labels in scope
46
Finished products in the current FDA directory
48
Companies listing them (makers, repackagers, distributors)
23
FDA labeler codes behind them ⓘ
26
Linked representative label ⓘ
Elite Laboratories, Inc.
Linked label effective
May 21, 2026
Composite sections available
20
Linked SPL Set ID
5f188bdc-2009-43aa-ad32-f06dbfac2642
Linked SPL Document ID
ce3d9c35-a4f0-43ab-862d-2b5def348737
Open the linked representative label on DailyMed ↗

How this page is built

HelloPharmacist combines public FDA and NLM records and does not author the underlying clinical facts. The plain-language sections are written with AI from the FDA-approved label text and reviewed by our pharmacy team before publication. Elite Laboratories, Inc. is the representative DailyMed label linked for verification and dates. This is general education, not medical advice: always talk to your doctor or pharmacist about your own medicines. How we build and review drug pages →