What Is Naltrexone & What Is It Used For?


Addiction comes in many forms, and among the most difficult ones involve opioids and alcohol. Among the medications that doctors can prescribe to help patients get over their addiction is naltrexone; but what is naltrexone?

This drug is primarily used to help you deal with opioid dependence, but it’s also commonly used with chronic alcohol dependence. This post discusses everything about the drug, its mechanism of action, precautions, and side effects.

Naltrexone: What Is It and What’s It Used For?

Naltrexone is a prescription medication that doctors give to patients who suffer from Alcohol Use Disorder (AUD) or Opioid Use Disorder (OUD). It’s a type of medication-assisted treatment, or MAT, which is a combination of counseling and medication to help patients overcome their addiction.

Naltrexone is available in pill and injectable forms. The 50 mg pill should be taken once per day at fixed times to achieve the ideal effect. The injectable or extended-release form is used at 380 mg intramuscular injection monthly.

What Is the Naltrexone Mechanism of Action?

Naltrexone is a pure opioid receptor antagonist. It binds to opioid receptors in the brain – the same ones that opioid drugs bind to – and blocks such drugs from achieving their effect on the brain.

How Does Naltrexone Help in Opioid Addiction?

Opioid receptors are responsible for pain relief, mood regulation, and a highly sought-after “feeling of satisfaction.” When opioids bind to such receptors, they elicit positive feelings in a way that can be addictive to the patient.

Using naltrexone to prevent the opioids from working on receptors allows the body to recover and get back to relying on the opioids produced naturally.

How Does Naltrexone Help in Alcohol Addiction?

Naltrexone’s exact mechanism in dealing with alcohol dependence is yet to be fully understood. The theory is that it works by blocking the effects of endogenous opioids like endorphins and beta-endorphins.

Endorphins are opioids that the brain releases when you drink alcohol, and they’re the ones responsible for that “pleasure” effect that people get upon drinking alcohol. Naltrexone blocks the effect of alcohol, making it less rewarding and discouraging the person from consuming it.

Is Naltrexone Dangerous?

Like any medication, naltrexone does have a list of side effects, which we’ll discuss in a moment. However, there’s a particular risk that can be fatal if ignored.

Naltrexone works by blocking the effect of opioids on the brain receptors. Opioid addiction comes from the “good feeling” people experience upon taking the opioid. When the patient is taking naltrexone, the opioid will have little to no effect on them.

Because of this, some patients resort to taking higher doses of opioids to feel their effects, which can lead to a fatal opioid overdose.

A similar risk can also occur if the patient takes opioids after an extended-release injection of naltrexone has worn off.

Over time, the effect of extended-release naltrexone will slowly decrease until complete disappearance. Patients who use the drug for a long period become more sensitive to opioids.

In other words, the dose that the patient used to consider a regular dose might now become a fatal opioid overdose because the body will be more sensitive to it.

Naltrexone Side Effects

Despite being safe, naltrexone has a fair share of side effects. Some of the common ones include:

  • Muscle cramps and painful joints
  • Nausea, dizziness, and vomiting
  • Headache
  • Trouble sleeping
  • Cold symptoms
  • Toothache
  • Loss of appetite

Although uncomfortable, these symptoms shouldn’t be a cause for concern as long as none of them is severely affecting the patient’s quality of life. Further, symptoms like nausea and vomiting should subside or even disappear with time.

There are less common side effects that you may experience with naltrexone. However, you should immediately inform your doctor if you experience any of them. These include:

Intense Allergic Reactions

The skin will be severely irritated and may exhibit:

  • Skin rash
  • Face swelling
  • Eye swelling
  • Blisters

Liver Damage

The patient might experience liver complications that manifest as:

  • Yellowing of eyes (jaundice)
  • Pain lasting in the stomach area that persists for several days
  • Dark urine

Severe Injection Site Reactions

Patients who take the injection form of naltrexone might suffer from:

  • Intense pain at the injection site
  • Lumps or hard areas at the injection site
  • Scabs and open wounds (rare)

Precautions While Using Naltrexone

Here are a few things to keep in mind while using naltrexone:

1. It Won’t Work for Everyone

We mentioned earlier that naltrexone is a medication-assisted treatment. In other words, it’s often used as a part of a larger comprehensive treatment.

Other medications, alternative therapies, and counseling could also be involved in the program. If the prognosis of the treatment as a whole isn’t favorable, naltrexone alone won’t solve the addiction problem.

2. It Needs the Patient’s Will

Naltrexone doesn’t “treat” the patient’s addiction; it only makes the effect of opioids and alcohol less satisfying to the patient, which can discourage them from using the substances. Unfortunately, some patients stop using naltrexone and go back to their opioids.

3. It Shouldn’t Be Used If the Patient Has Opioid Withdrawal Symptoms

Patients shouldn’t start their naltrexone treatment unless the withdrawal symptoms have subsided or at least started to lessen in severity. Using naltrexone while the symptoms are active will precipitate the symptoms, especially if the patient is too dependent on opioids.

Further, patients who are currently experiencing withdrawal symptoms will be less likely to get any real help from naltrexone because they would be craving the opioid they’re addicted to. With the reduced sensitivity they’d have to that opioid, they might overdose while attempting to get that rewarding feeling.

4. It Shouldn’t Be Taken With Other Drugs Without the Doctor’s Supervision

Naltrexone’s interaction with other drugs, especially opioid painkillers, can be highly unpredictable. It can also interact with prescription and even some OTC drugs. As such, it’s paramount to not take naltrexone without a doctor’s prescription, assuming that you’ve already informed the doctor about all the medications you are currently on.

5. It Mustn’t Be Taken If the Patient Has Liver Problems

Naltrexone can cause problems to a healthy liver. Because of that, it’s necessary to avoid taking it if the patient has any liver issues like cirrhosis or hepatitis.

In Conclusion

Naltrexone, paired with the patient’s commitment and community support, can go a long way in treating opioid and alcohol dependence. Make sure that you don’t consume this drug without your doctor’s prescription and that you report any serious side effects immediately.

Also, don’t forget the considerations we mentioned earlier, as naltrexone isn’t suitable for just anyone. If you want to begin your substance addiction treatment, the Curednation team is happy to help. Reach out to us today to learn more.


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