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Naltrex

Naltrex 4.5MG

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What is Naltrex?

Naltrex is a medication used to help people who are struggling with alcohol or opioid dependence. It works by blocking the effects of these substances, helping to reduce cravings and the urge to use them.

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What is Naltrex ?

Naltrex is a medication used to help people who are struggling with alcohol or opioid dependence. It works by blocking the effects of these substances, helping to reduce cravings and the urge to use them.

  • Nausea
  • Headache
  • Dizziness
  • Fatigue
  • Insomnia
  • Vomiting
  • Anxiety
  • Muscle or joint pain
  • Do not use opioid drugs while taking this medication to avoid severe withdrawal symptoms.
  • Patients with acute hepatitis or liver failure should avoid using this medication.
  • Use cautiously in patients with a current or previous history of depression.
  • Can cause hepatotoxicity; liver function tests should be conducted regularly.
What is naltrexone used for?

Naltrexone is FDA-approved to treat alcohol use disorder, helping people maintain abstinence, and to prevent relapse to opioid dependence after a person has completed opioid detoxification. It works best combined with counseling and psychosocial support. It is also prescribed off-label at low doses for other conditions, but those uses are not FDA-approved.

Is naltrexone a controlled substance?

No. Naltrexone is not a controlled substance. It is an opioid antagonist, meaning it blocks the effects of opioids rather than producing an opioid-like effect, and it is not habit-forming.

How long after taking opioids can you start naltrexone?

You generally need to be opioid-free for about 7 to 10 days before starting naltrexone. Starting it while opioids are still in your system can precipitate acute opioid withdrawal. Your provider will confirm the right timing for you.

What is the difference between oral naltrexone and Vivitrol?

Both contain the same medicine and share the same approved uses. Oral naltrexone is a tablet taken by mouth, usually 50 mg per day. Vivitrol is an extended-release injection (380 mg) given into the muscle once a month, which can help people who have trouble taking a daily pill. Vivitrol is a brand product and generally costs more than generic oral naltrexone.

Does naltrexone have side effects on the liver?

Naltrexone can cause dose-related liver injury, so it is not used in people with acute hepatitis or liver failure, and providers may check liver function during treatment. Tell your provider if you have any history of liver problems or develop symptoms such as yellowing skin, dark urine, or stomach pain.

How much does Naltrex 4.5MG cost without insurance?
The price of Naltrex 4.5MG without insurance varies by pharmacy, dosage, and quantity. Rx.com compares cash prices at more than 60,000 US pharmacies so you can find the lowest price near you. Many people save 60–90% off retail prices with a free Rx.com coupon.
What are the common side effects of Naltrex 4.5MG?
Common side effects of Naltrex 4.5MG may include: Nausea, Headache, Dizziness, Fatigue, Insomnia. This is not a complete list — consult your pharmacist or doctor for full side effect information.
Is there a generic version of Naltrex 4.5MG?
Generic versions may be available for Naltrex 4.5MG. Generics contain the same active ingredients as brand-name drugs and are typically 80–90% cheaper. Search Naltrex 4.5MG on Rx.com to compare generic and brand prices at pharmacies near you.
What is the cheapest pharmacy for Naltrex 4.5MG?
The cheapest pharmacy for Naltrex 4.5MG depends on your location and dosage. Rx.com compares prices at CVS, Walgreens, Walmart, Kroger, Costco, and thousands of independent pharmacies. Enter your ZIP code on Rx.com to find the lowest price for Naltrex 4.5MG near you.

Naltrex Coupons & Prices

Naltrex 4.5MG

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Naltrex Capsule — prescription drug image
Prescription
Naltrex 4.5mg (14)
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Compounded GLP-1 medications are not FDA-approved and are prepared by state-licensed compounding pharmacies. They are not affiliated with, endorsed by, or equivalent to any brand-name medication or manufacturer. Prescription required; eligibility is determined by a licensed provider. Prices are estimates and may vary.

Looking for a naltrex coupon? Naltrexone is the low-cost generic form of the opioid antagonist once sold as the oral brands ReVia and Depade (now discontinued in the US), and it is still available as the long-acting injection Vivitrol. Because naltrexone is generic, cash prices are often modest, but they can still vary a lot from one pharmacy to the next, so comparing matters. Enter your ZIP code above to see today's naltrexone price at pharmacies near you. Rx.com compares prices across 60,000+ pharmacies so you can find a low cash price without insurance.

What is naltrexone and how does it work?

Naltrexone is an opioid antagonist, meaning it attaches to opioid receptors in the body and blocks the effects of opioids. It is FDA-approved to treat alcohol use disorder (to help people maintain abstinence) and to prevent relapse to opioid dependence after a person has completed opioid detoxification. It is meant to be used alongside counseling and other psychosocial support, not on its own.

It comes in two main forms: an oral tablet (typically 50 mg per day) and an extended-release injection called Vivitrol (380 mg given into the muscle once a month). Both share the same approved uses. Naltrexone is also frequently prescribed off-label at much lower doses ("low-dose naltrexone") for conditions such as chronic pain and certain autoimmune diseases, but those uses are not FDA-approved. Only your provider can decide whether naltrexone is right for you.

Naltrexone cost and coupons without insurance

Naltrexone is a generic, so it is generally one of the more affordable options in its class, especially in the oral tablet form. Even so, the cash price you pay can differ widely depending on which pharmacy you use and where you live, which is exactly why it helps to compare before you fill. Rx.com checks prices across 60,000+ pharmacies so you can see the lowest available cash price near you. Enter your ZIP above to see today's price.

The extended-release injection Vivitrol is a separate brand product and typically costs more than oral generic naltrexone. Vivitrol's manufacturer offers a co-pay savings program for eligible, commercially insured patients; you can review the details and eligibility terms directly on the official page at vivitrol.com. Terms and eligibility vary, so check the manufacturer's site for current conditions.

Naltrexone vs. related and alternative treatments

Naltrexone is one of several medicines used for alcohol and opioid use disorders, and the right choice depends on your situation and your provider's guidance. Related products and alternatives include:

  • Vivitrol — the extended-release, once-monthly injectable form of naltrexone.
  • Acamprosate and disulfiram — other medicines used to support recovery from alcohol use disorder.
  • Buprenorphine and Suboxone — opioid-based treatments for opioid dependence that work differently from naltrexone.
  • Contrave (also sold as naltrexone-bupropion) — a separate combination product used for weight management, not the same as naltrexone used for addiction treatment.

These medicines are not interchangeable. Your provider can help you decide which approach fits your needs.

Important safety information

This is general information, not medical advice. Always follow your provider's instructions. A few key safety points for naltrexone:

  • Be opioid-free first. You typically need to be off opioids for about 7 to 10 days before starting naltrexone. Starting too soon can trigger sudden, severe opioid withdrawal.
  • Do not try to override the blockade. Naltrexone blocks opioids. Taking large amounts of opioids to overcome it, or relapsing after treatment when your tolerance has dropped, can lead to serious injury, overdose, coma, or death.
  • Liver health. Naltrexone can cause dose-related liver injury. It is not for people with acute hepatitis or liver failure, and providers may monitor liver function during treatment.
  • Injection-site reactions can occur with the Vivitrol injection, and some people experience mood changes such as depression. Tell your provider about any changes in mood.

Naltrexone is not a controlled substance. If you need emergency pain care, tell the medical team you take naltrexone, since the opioid blockade can complicate pain management.

Sources & accuracy

This Naltrex information was written and reviewed against authoritative U.S. medical sources — MedlinePlus (U.S. National Library of Medicine), DailyMed, and FDA prescribing information — and checked for accuracy. It is provided for education and is not a substitute for professional medical advice.

Verify the official label: Naltrex on DailyMed (FDA)

Reviewed against FDA labeling · Last reviewed July 2026

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Medical disclaimer: This information is provided for general educational purposes only and is not medical advice. It is not a substitute for professional diagnosis or treatment. Always consult a licensed physician, pharmacist, or other qualified healthcare provider before starting, stopping, or changing any medication or treatment. Never disregard professional medical advice or delay seeking it because of something you read here. If you think you may have a medical emergency, call your doctor or 911 immediately.


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