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Naltrexone – Uses, Side Effects and Benefits

Brand Names of Naltrexone: Revia and Vivitrol
Drug Class: Opioid Antagonist

What Is Naltrexone?

Naltrexone (Revia) is an opioid antagonist drug. Doctors prescribe Naltrexone to reverse and block the effects of endogenous opioids, and it prevents the effects through a process called competitive binding. There are minimum effects besides its blocking properties. This medication is an integral part of the treatment for people who have been suffering from opioid use disorder. When taken correctly, this medication can significantly prevent you from craving opioids which will substantially help during your recovery process – a great prevention tool among many.

This medication is an essential part of drug treatment when used in conjunction with counseling or other mental health support options. However, it should not be taken by people who are currently taking opioids including methadone, fentanyl, or suboxone because of the risk for sudden withdrawal symptoms.”

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Naltrexone Risks and Side Effects

Some Potential Risks:

  • Patients currently taking opioids should not take Naltrexone, including those on maintenance drugs, like methadone, or partial agonists, such as buprenorphine. Moreover, severe withdrawal syndrome can develop in as little as five minutes after taking a dose and can last for a couple of days. Immediate medical assistance and monitoring are required because symptoms can include confusion, hallucinations, and significant loss of fluids due to intense vomiting and diarrhea.
  • It is potentially hazardous for individuals to attempt, on their own, to overcome the Naltrexone blockade by taking large amounts of exogenous opioids. Any attempt by the person to overcome the antagonist may lead to life-threatening intoxication, including respiratory arrest and circulatory collapse or even a fatal overdose. Ultimately, patients should be acutely aware of the severe consequences of overcoming the opioid blockade.
  • Patients who recently received treatment with Naltrexone are likely to have a reduced tolerance to opioids. They may also have a quicker and stronger response to lower doses of opioids than before taking Naltrexone, similarly to after completing detoxification. If the patient tries using previously tolerated opioid doses, it could result in an overdose.

Naltrexone Side Effects:

Naltrexone may also cause unwanted symptoms or side effects along with its intended effects. Although most people tolerate an adequate dose, some effects may occur. Please call your prescribing physician or seek medical attention if they do happen. Before starting this therapy, patients should provide their prescribing physician with a comprehensive medical history and a complete list of current medications (including over-the-counter drugs). Additionally, narcotics, diarrhea medications, disulfiram, and cough medication can adversely interact with Naltrexone.

Check with your doctor immediately if any of the following side effects occur while taking Naltrexone:
For example, common naltrexone side effects are:

  • abdominal cramping (mild to moderate)
  • anxiety
  • restlessness
  • trouble sleeping
  • headache
  • muscle pain
  • nausea or vomiting
  • tiredness

Less Common Side Effects:

  • chills
  • constipation
  • cough
  • hoarseness or a sore throat
  • sinus problems
  • runny nose
  • diarrhea
  • dizziness
  • rapid heartbeat
  • unusual thirst
  • loss of appetite
  • sexual issues in males

Discuss the risks and benefits of Naltrexone treatment with your doctor. Consider stopping using this medication and tell your doctor right away if you develop severe naltrexone side effects. These symptoms may include persistent nausea/vomiting, abdominal pain, dark urine, and yellowing of eyes or skin, and these signs could indicate rare liver issues.

Allergic reaction to this drug is rare; however, if you notice any symptoms such as a rash, itching or swelling (especially the face/tongue/throat), dizziness, trouble breathing, and getting emergency medical help right away.

The information above is NOT a complete list of possible risks and side effects and should NOT be used for medical decisions. contact your doctor or pharmacist if you notice any other symptoms that are not listed above, or would like additional information.

Naltrexone and Vivitrol Differences

Naltrexone and Vivitrol are both medications classified as opioid antagonists, they work by blocking the effects of opioids on the brain. 

One of the key differences between Naltrexone and Vivitrol is their administration method. Naltrexone is taken orally as a daily pill, whereas Vivitrol is administered as a monthly injection. This can be an important consideration for patients who have difficulty with medication adherence or who may face challenges in accessing their medication.


Another difference between Naltrexone and Vivitrol is their duration of action. Naltrexone is effective for approximately 24 hours after each dose, while Vivitrol provides protection against opioid and alcohol use for a full month. This extended duration of action can be particularly beneficial for patients who struggle with cravings or who may face relapse triggers over the course of a month.


It’s worth noting that both medications can cause side effects, although these are generally mild and well-tolerated. Common side effects of Naltrexone and Vivitrol include nausea, headache, dizziness, and fatigue. In rare cases, more serious side effects such as liver damage or allergic reactions can occur. It’s important to discuss any concerns or questions you may have about medication options with a healthcare provider.

Is Naltrexone the same as Suboxone and Methadone?

Absolutely not. Naltrexone is not an opioid drug and for that reason, it is not addictive and does not cause withdrawal symptoms when you stop taking the medication. Now, Suboxone and Methadone are both opioid narcotics with a high affinity to the receptors and extremely addictive drugs. Although there is Naltrexone within the Suboxone, the active addictive ingredient is the opiate and not the antagonist.

Naltrexone Treatment Benefits

If you are seeking a rehabilitation center for you or a loved one, consider the safety and effectiveness of the detoxification and the benefits of a naltrexone treatment program.

Naltrexone has the ability to assist significantly in reducing physical cravings for opioid drugs by binding to the receptor sites. The medication helps in blocking the euphoric and sedative effects of drugs such as heroin, morphine, and codeine.

It is essential to achieve complete opioid detoxification before commencing Naltrexone therapy. When patients go through a non-accelerated method of detoxification, the recommended time of abstinence from an opioid drug is at least 7 to 10 days. However, in the event a rapid detox treatment was the chosen detoxification method, naltrexone therapy can be initiated immediately to reduce relapse risk.

Before someone can begin naltrexone therapy, they must be appropriately screened and assessed. Also, the patient must be completely opioid-free. A comprehensive physical examination that can identify any medical issues (such as liver disease) should also be done prior to taking this medication.

Naltrexone Treatment for Opioid Addiction

Naltrexone is a pure mu antagonist. Studies show that in highly motivated patients, Naltrexone treatment is a helpful post detoxification option, and It can be taken by mouth once daily or even every other day. It has minimal side effects and is neither addicting nor has the potential for abuse. Therefore, it has become a favorable treatment choice for those who desire total abstinence.

Opioid addiction can be a very complicated and frustrating condition. Even for those who successfully achieved detoxification, physical cravings can be overwhelming and lead to relapse. Naltrexone dramatically reduces the desire to use opioids for those struggling with cravings. The drug is an essential component of an effective opioid treatment. With the combination of this medication, sober time, individual mental health assistance, the chances to remain opiate-free are much higher.

Effective medical detoxification is an essential first step for people who abuse heroin and opioid medications. However, choosing the proper detox is a complicated and confusing task. Naltrexone therapy can only begin once a person completely detoxes from opioids. Patients attempting ‘cold turkey’ detox must have remained off all opioids for at least 14-28 days, depending on the specific drug and usage. Most of these patients cannot start a Vivitrol or Naltrexone therapy because they cannot endure the suffering of a ‘cold turkey detox. Withdrawal symptoms can be challenging and stressful, making the required time off opiates nearly impossible for so many.

Rapid Detox and Naltrexone

Naltrexone treatment might sound like a new approach for you, but the truth is, the Waismann Method physicians have been using this medication, in conjunction with medical detox, for over two decades.

At Waismann Method, we recommend oral Naltrexone to most of our patients after rapid drug detox. It helps reduce relapse due to physical cravings and sudden temptations, and it also has a potent binding affinity to the opioid receptors what contributes to ensuring continued abstinence. This drug’s oral form allows our physician to modify dosage and intake based on each patient’s medical needs, conditions, and side effects. After the initial oral intake, patients also can choose the monthly injection of Vivitrol.

Waismann Method of Anesthesia Assisted Rapid Detox’s primary goal is to quickly and comfortably get patients free from opioid dependence. We recognize that day-to-day reality can be challenging and sometimes filled with opportunities for relapse. Furthermore, we understand that controlling physical cravings is just a part of the equation to maintain sobriety. Our 23 years of experience with rapid detox and opioid medical treatment have shown us that Naltrexone is a crucial reason for our patients’ continued success. Patients can begin emotional healing when they feel physically stable, and they concentrate on seeking peace of mind when their bodies no longer feel distressed. Naltrexone therapy helps patients focus on their psychological healing without physiological cravings.

Frequently Asked Questions

Naltrexone is not classified as a controlled substance in the United States. This means it has a lower potential for abuse compared to opioids and does not carry the same risk of dependence. It's important, however, to use naltrexone under the guidance of a healthcare professional to ensure its safe and effective use in treatment plans.

Naltrexone works by binding to the opioid receptors in the brain but, unlike opioid drugs, it does not activate these receptors. This action blocks the effects of opioids, such as pain relief or feelings of well-being that can lead to opioid abuse. Naltrexone is used in the treatment of alcohol and opioid dependence because it reduces the cravings and feelings associated with addiction, helping individuals maintain sobriety.

When taking low dose naltrexone (LDN), it's crucial to avoid:

Opioid medications: LDN can interfere with their effectiveness and lead to withdrawal symptoms.

Alcohol: While naltrexone is sometimes used to treat alcohol dependence, mixing it with alcohol can increase the risk of liver damage.

Certain over-the-counter medications: Especially those that may also have sedative effects.

Always consult with your healthcare provider for a comprehensive list of substances to avoid.

Naltrexone can stay in your system for about 24 to 72 hours, though its metabolites may be detectable for up to 4 days after the last dose. The exact duration can vary based on several factors, including the dosage taken, overall health, and metabolic rate of the individual.

Most side effects of low dose naltrexone are mild and temporary. Common side effects may include fatigue, insomnia, or gastrointestinal discomfort, which typically resolve within a few days to weeks of starting the medication. If side effects persist or become bothersome, it's advisable to speak with your healthcare provider for guidance and potential adjustments to your treatment plan.

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