What is Naltrexone?

Adapted from : http://pubs.niaaa.nih.gov/publications/combine/appendixC.htm#c1

Naltrexone is not Naloxone.
Do not use it to reverse opioid overdose.
It will produce acute, severe, and uncontrollable withdrawal … that can be fatal.

1. What is Naltrexone, and how does it work?

Naltrexone is an opioid blocker. It attaches to opioid receptors and blocks the effects of drugs known as opiates, or narcotics (a class that includes drugs like morphine, heroin, codeine, hydrocodone, oxycodone, fentanyl, opana, etc).

These opioid receptors when triggered have an important role in experiencing pleasure, and thereby developing habits by way of positive reinforcement.

It is believed that by blocking these receptors Naltrexone reduces the sensation of pleasure in response to substances like opioids and alcohol, and thereby removes or diminishes the desire to use them.

This principle has seen Naltrexone being advocated for other pleasure, reward, development of harmful habit pathways. Naltrexone, for a similar reason has been recently approved in combination with Bupropion (Contrave) as a medication for the management of Obesity.

Naltrexone was originally used to treat dependence on opiate drugs. It is now approved by the U.S. Food and Drug Administration (FDA) as treatment for alcohol dependence. If you are dependent on opiate drugs, such as heroin or morphine, you must stop your drug use at least 7 days prior to starting Naltrexone.

Some people should not take Naltrexone, such as those suffering from chronic pain who rely on opioid painkillers or people with liver failure or acute hepatitis.

This is not an absolute contraindication … in low doses Naltrexone has not been shown to cause any significant increase in liver enzymes. If you are using alcohol while you have elevated liver enzymes then you might as well try Naltrexone. Naltrexone can be stopped if serum enzymes indicative of liver injury continue to rise.

Reports from clinical trials have shown that patients who took Naltrexone:

  • had a reduced urge to drink.
  • and if they did drink … they drank less.

In most clinical trials evaluating the effectiveness of Naltrexone, subjects who received naltrexone were significantly more successful in remaining abstinent and in avoiding relapse than were those receiving an inactive placebo pill.

2. Is it possible to become addicted to Naltrexone?

No. Naltrexone is not habit forming or a drug of abuse. It does not cause users to become physically or psychologically dependent.

3. What are the side effects of Naltrexone?

In a large open-label safety study on naltrexone, conducted by Dupont Pharma in 570 individuals with alcoholism, the most common side effects affected only a small minority of people; they included the following:

  • Nausea (10 percent of participants)
  • Headache (7 percent of participants)
  • Depression (5 to 7 percent of participants)
  • Dizziness (4 percent of participants)
  • Fatigue (4 percent of participants)
  • Insomnia (3 percent of participants)
  • Anxiety (2 percent of participants)
  • Sleepiness (2 percent of participants).

These side effects were usually mild and of short duration. The side effects, predominantly nausea, have been severe enough to cause 5 to 10 percent of people starting it to stop the medication.

Patients usually report that they are largely unaware of being on Naltrexone.

Naltrexone usually has no psychological effects, and users do not feel either “high” or “down.”

Naltrexone can have toxic effects on the liver if taken in high doses.

You will receive blood tests of liver function prior to the onset of treatment and regularly during treatment to determine if you should take it at all, if you should stop taking it, or if you experience the relatively rare side effect of liver toxicity. You should report any side effects to your medical clinician.

4. What will happen if I drink alcohol while taking Naltrexone?

Naltrexone does not interact with alcohol.

Naltrexone may reduce your feeling of intoxication and reduce the desire to drink, but it will not cause any reaction with alcohol.

Naltrexone does not reduce the effects of alcohol that impair coordination and judgment, that is, if you drink while you are on Naltrexone you will still be impaired.

5. Is it all right to take other medications with Naltrexone?

You can not take any opioid pain relievers while on Naltrexone … they will not work.

You should carry a card explaining that you are on Naltrexone, which instructs medical staff on pain management. Naltrexone does not reduce the effectiveness of local and general anesthesia used with surgery.

Naltrexone will block pain relief from opiate medications.

Your emergency room physician, surgeon, and anesthesiologist, need to know that you are on Naltrexone, because they will need to modify your pain management and anesthesia plan.

If you are having elective surgery, you should stop taking naltrexone at least 72 hours beforehand.

There are many nonnarcotic pain relievers you can use while on Naltrexone such as aspirin, acetaminophen (Tylenol), ibuprofen (Motrin / Advil).

Naltrexone does not interact with allergy medications.

You should inform your medical provider of the medication you are currently taking so that possible interactions can be evaluated.

Because the liver breaks down Naltrexone, other medications that can affect liver function may affect the dose of Naltrexone.

Naltrexone does not cause any sedation or alteration of mental status. Patients can drive, and work with machinery.

Outpatient treatment with Naltrexone and counseling is available at a fraction of the cost of residential rehab. Residential rehab costs about $15000 to $30000.

Outpatient treatment with Naltrexone costs less than $300 per month. You live with your family, continue to work, and take the medications in the comfort and privacy of your home.

6. What will happen if I become pregnant while taking Naltrexone?

Current recommendation is to stop taking Naltrexone if you become pregnant.

If you have the biological potential to have a child, you should be using an effective method of birth control while taking Naltrexone. However, if you miss a menstrual period, report this to your medical provider at once and take a pregnancy test. If you become pregnant, you will discontinue the medication.

Your medical provider should continue to ask about your health throughout your pregnancy and also about the health of your baby after delivery.

Naltrexone has been assigned to pregnancy category C by the FDA. Animal studies have revealed evidence of an embryocidal effect when given in doses approximately 30 to 60 times the human therapeutic dose.

There are no adequate and controlled study data in human pregnancy.

One will have to weigh the risk vs benefit. Continued alcohol use during pregnancy also carries risks, so potential benefits may warrant use of the drug in pregnant women despite potential risks. It would be best if alcohol use can be discontinued by some other means.

7. Should I take Naltrexone with or without a meal?

Taking Naltrexone with or without meals does not make any difference in effect.

8. What happens if I stop taking Naltrexone suddenly?

Naltrexone does not cause physical dependence, and you can stop taking it at any time without experiencing withdrawal symptoms.

9. If I take Naltrexone, does it mean that I don’t need other treatment for alcohol dependence?

No. Research studies have shown that Naltrexone was most effective when it was combined with treatment from professionals and/or mutual-support groups.

Addiction is not cured by a pill … it is a behavior problem and the behavior needs to be changed.

You will have much better results if you consult a drug abuse counselor or a cognitive behavior therapist and follow a lesson plan to modify your alcohol use behavior.

10. What is the relationship of Naltrexone to AA and other mutual-support groups?

There is no contradiction between participating in support groups and taking Naltrexone. In fact, one multisite study showed that Naltrexone-taking subjects who attended mutual-support groups, such as AA, had better outcomes. It is most likely to be effective for you if your goal is to stop drinking altogether.

If other mutual-support group members caution against taking any medications, you should refer them to the pamphlet “The AA Member—Medications and Other Drugs,” which explicitly states that AA members should not “play doctor” and advise others on medication provided by legitimate, informed medical practitioners or treatment programs.

If your group members are ignorant about medication assisted recovery … just find another group.

11. What is the cost of treatment with Naltrexone

Naltrexone 50mg tablet is prescribed as one tablet once a day. It costs $1 to $2 per tablet. Monthly cost for 30 tablets is $30 to $60.

Naltrexone is also available as an injection taken once a month. The cost is $1000 to $1200 per injection.

For the cost of less than a beer per day you could be on your way to reduced drinking and improved health.

It could save your life, your job, your marriage, your home, … and keep you out of jail. Don’t let alcoholism ruin your life.

12. Who can prescribe Naltrexone?

Naltrexone is not a controlled substance. Any Medical provider with authority to prescribe medications can prescribe Naltrexone. As a practical matter … primary care providers, psychiatrists, and doctors who are familiar with and treat addiction, … are more likely to prescribe it.

13. Are there any other medications that are useful in treatment of alcohol addiction?

FDA approved medications are Acamprosate (Campral), and Disulfiram (Antabuse).

Another medication Nalmefene (also an opioid blocker) is available in Europe. Nalmefene has not been linked to serum enzyme elevations during therapy or to clinically apparent liver injury, so it has been the preferred drug of choice for patients with alcoholic cirrhosis or hepatitis.

Nalmefene is available as a once a day tablet … and is currently being used in Europe as an aid in the treatment of alcohol addiction.

Nalmefene is not yet approved in USA for this indication, and has not been made available as a tablet.

There are anecdotal reports of other medications being helpful in the treatment of alcohol addiction, such as,… Fluoxetine (Prozac), Sertraline (Zoloft), Topiramate (Topamax), Ondansitron (Zofran), Baclofen, Gabapentin (Neurontin), Buprenorphine (Suboxone), Bupropion (Welbutrin), etc.

At present none of the above drugs have been approved by the FDA for the treatment of alcohol addiction.


Medication guides

Naltrexone – Revia

Vivitrol Injection


This page was last modified on: December 7, 2016