Naltrexone was approved by the FDA during the mid 1980s for use by those trying to detox from heroin and opium. It was also found to be effective on those suffering from certain infections and cancer.

What is Naltrexone?



Naltrexone takes the reward of getting high away from the opiate-dependent individual. It blocks opioids from acting on the brain so the user feels no effect from the drug. In addition, this medication is used to help stop cravings. If a person takes naltrexone and then uses opioids, not only will the effects of the opioids be blocked, but the person may also experience opiate withdrawal symptoms.

Uses of Naltrexone

Naltrexone is not a narcotic, but it does block serotonin and dopamine, the naturally occurring opioid neurotransmitters in the brain from attaching to a cell or nerve receptors in the body. There are opiate receptors in the brain, spine, and the gastrointestinal tract. Naltrexone is also used in treatment for alcohol dependence. The use of naltrexone will not stop alcohol intoxication after drinking; it will only stop the pleasurable sensations associated with drinking alcohol. The amount of alcohol consumed will not override the effects of naltrexone, so the sensation of being high will never be achieved.

Naltrexone is a medication that was originally introduced under the name Revia. It is also available as a once a month intramuscular injection called Vivitrol. The administration of the once a month injection must be done in a licensed Naltrexone physician’s office.

Naltrexone was developed to be used as part of alcohol addiction treatment and works when used appropriately and the alcoholic is not drinking. It is not a substitute for alcohol rehabilitation, relapse prevention skills or understanding the underlying psychological reasons for substance abuse that can only be learned while in a drug rehab center.

Naltrexone and Alcohol Addiction

Alcohol dependence is a serious illness that can ensnare a person regardless of age, gender, income, class or religion. It is defined as the repeated use of alcohol despite the occurrence of negative consequences in the user’s life. Once an individual becomes physiologically dependent on alcohol or addicted to alcohol, a condition known as alcoholism, withdrawal occurs if alcohol intake is not increased. Alcohol withdrawal symptoms can be life-threatening. A major characteristic of alcohol dependence is the intense cravings associated with withdrawal and tolerance.

Other signs and symptoms of alcohol addiction include:

  • Inability to limit the amount of alcohol consumed
  • Strong compulsion to drink
  • Tolerance for alcohol
  • Legal problems or problems with relationships, employment or finances due to drinking
  • Drinking alone or in secret
  • Experiencing physical withdrawal symptoms such as nausea, sweating and shaking when alcohol isn’t used
  • Not remembering conversations or commitments (sometimes referred to as "blacking out")
  • Making a ritual of having drinks at certain times and becoming annoyed or irritable when this ritual is disturbed or questioned
  • Losing interest in activities and hobbies that used to bring pleasure
  • Irritability when a usual drinking time nears, especially if alcohol isn't available
  • Hiding alcohol in unlikely places at home, at work or in the car

Naltrexone should not be used within 5 days of alcohol withdrawal, as negative side effects will be induced.

How Does Naltrexone Work?

Naltrexone binds to the opiate receptors in the brain and blocks their function, thereby blocking the sensation of pleasure that is produced by drinking alcohol. If a person does drink while taking naltrexone, he or she will continue to experience a lessening of inhibition leading to risky behavior, sedation, and depression. In other words, a drink will still cause intoxication and impairment, but the user will feel no pleasure throughout the experience. Taking naltrexone will not help you drive more safely or operate machinery after you’ve had a drink.

A person who drinks while taking naltrexone may feel sick and suffer from withdrawal symptoms such as:

  • Nausea
  • Diarrhea
  • Tremors
  • Depression

The dynamic relationship between naltrexone and brain receptors may help prevent thoughts of drinking or impulsive actions that lead to relapse. In addition, an individual will not experience highs or lows when taking naltrexone. Naltrexone can be taken in pill form or injected monthly using its injectable form known as Vivitrol. There are no withdrawal symptoms when an individual stops taking naltrexone.

Clinical trials for this medication were done with a focus on alcohol. The drug was found to be effective in limiting the number and duration of drinking days in individuals.

Vivitrol (Injectable Naltrexone)

Vivitrol is an intramuscular injectable form of naltrexone designed to be used once a month. It is never to be used intravenously or subcutaneously (under the skin) and should always be administered by a healthcare professional.

It should be noted that whether naltrexone is taken in pill form or injected, therapy and addiction treatment are part of the entire treatment protocol. Naltrexone alone will not address underlying reasons for drinking.

Side Effects of Vivitrol

More people tend to have side effects when being treated with Vivitrol than oral naltrexone. These side effects include:

  • Vomiting
  • Nausea
  • Injection site reactions
  • Eosinophilic pneumonia ( a type of autoimmune infection in which the white blood cells increase in the lungs)

Oral Naltrexone Side Effects

Naltrexone dosage and side effects depend on a person’s body and how the drug is absorbed. If you are having side effects or pain, tell your prescribing physician. Ingesting opioids when taking naltrexone is extremely dangerous as opiates combined with naltrexone can induce coma or death.

As with any drug, there are side effects with naltrexone. They are usually not ongoing and generally do not affect an individual’s daily living.

Naltrexone Side effects may include:

  • Weakness
  • Diarrhea
  • Nausea
  • Pruritus (itching of the skin, allergic dermatitis, or rash)
  • Anxiety
  • Lethargy/low energy
  • Insomnia
  • Muscle pain
  • Liver enzyme increase

Not everyone suffers from these side effects and initial problems of nausea usually disappear after a few days. Liver enzyme increases are rare.

Naltrexone is considered part of a full treatment experience to increase the chances of abstinence from substance abuse. A full treatment experience may include:

Safety Concerns Related to Naltrexone

Naltrexone is an FDA approved medication and is considered safe when used as directed. It was initially approved to treat opiate addiction in 1985. It is regularly prescribed not in only in the United States, but also in other countries around the world. There are minimal concerns regarding naltrexone posing a permanent problem to an individual’s health.

It is important to wear a bracelet identifying naltrexone use in case of an emergency, especially when taking naltrexone in its injectable form.

Control of liver enzyme levels prior to initiation of treatment with naltrexone as well as monitoring of those levels throughout treatment is recommended. People who have acute hepatitis, liver disease or kidney disease should not take naltrexone. Patients who are using narcotic painkillers should not take naltrexone nor should anyone who is allergic to any other drugs. Naltrexone therapy should commence 7-10 days after detoxification has occurred. In addition, naltrexone’s benefits are not a substitute for drug detox or drug addiction treatment. It is designed to be a component of addiction treatment.

Do You Have Questions About Naltrexone?

Call Recovery Connection to speak with one of our addiction specialists. Our representatives can answer questions about Naltrexone, what services are available, and how we can help you begin your journey toward long-term recovery.