Get help today 888-287-0471 or sign up for 24/7 text support.
American Addiction Centers National Rehabs Directory

What You Should Know About a Naltrexone Overdose

Naltrexone is a special drug that works as an opioid receptor antagonist. It blocks the effects of certain narcotic medications and alcohol. Taking large amounts of this drug can induce naltrexone overdose symptoms. Do not take narcotic painkillers or drink alcohol while you are using naltrexone, as doing so can cause adverse side effects, including opioid overdose or alcohol poisoning.

Indications and Side Effects of Using

Naltrexone is one of the few drugs approved by the Food and Drug Administration (FDA) for the treatment of alcoholism and opioid addiction. It is not used for relieving withdrawal symptoms or indicated for the treatment of an opioid or alcohol overdose. Naltrexone administration is often started after the patient has been off alcohol or opioids for about 7 to 10 days. A person may suffer from naltrexone overdose symptoms if they used the drug before withdrawing from opioid dependence.

A newer option for opioid treatment is the naltrexone implant, which is surgically placed under the skin. It is not, however, approved by the FDA or the Australian Therapeutic Goods Administration. There are also 5 recorded incidents of opioid overdoses resulting in fatalities in Australia as a result of naltrexone implants.

Naltrexone is generally safe and well tolerated, but, like other prescription medications, it can cause some side effects early in the treatment. Naltrexone side effects may include:

  • Anxiety.
  • Restlessness.
  • Increased thirst.
  • Joint or muscle aches.
  • Fatigue.
  • Fainting or lightheadedness.
  • Insomnia.

A person who is allergic to the drug may experience symptoms similar to naltrexone overdose symptoms, including:

  • Blurred vision.
  • Hallucinations.
  • Tinnitus or ringing in the ears.
  • Nausea.
  • Decrease appetite.
  • Fast heartbeat.
  • Skin rash.
  • Breathing difficulties.

Naltrexone should not be administered to patients with liver disease or liver toxicity. Taking naltrexone while still in the alcohol or opioid withdrawal process may precipitate the withdrawal symptoms.

Causes of Overdose and Symptoms

Naltrexone is available in 50-mg tablets and a 380-mg extended-release injectable liquid solution for alcohol dependence. People addicted to it can take an initial dose of 12.5 mg or 25 mg per day and then shift to 50 mg if no withdrawal signs occur. The dose for adult opioid addiction may be increased to 100 mg during weekends or every other day to improve compliance.

Naltrexone overdose symptoms may occur if you:

  • Try to overcome the desired effects of this medication by ingesting large amounts of narcotics or alcohol.
  • Accidentally or intentionally take more than the prescribed dose.
  • Inject an extended-release suspension directly in your veins rather than in the gluteal muscles or buttocks.
  • Stop using naltrexone after chronic use, and then taking opioids again.
  • Are addicted to the drug and regularly take large amounts.

Signs of an overdose on naltrexone include:

  • Nausea.
  • Stomach pain.
  • Dizziness.
  • Seizures or convulsions.

In case of a naltrexone overdose, call your local emergency number (911) or the National Poison Control Center.

Treatment Options and Recovery

“A person who is suffering from naltrexone overdose symptoms should seek medical help immediately.”A person who is suffering from naltrexone overdose symptoms should seek medical help immediately.

Naltrexone overdose treatment may include:

  • Collecting blood and urine samples to determine the type of drugs present and if there were other substances taken, like alcohol and other medications along with the overdosed drug.
  • Activated charcoal to absorb any remaining drugs in the body and to slow down the absorption of the drug into the system.
  • Gastric lavage or stomach pumping, which involves the insertion of a flexible tube through the nose, down, the throat and into the stomach.
  • Using a saline solution during stomach pumping procedures to rinse the stomach after the stomach cleaning.
  • IV fluids to re-establish the balance of acids/bases, fluids and minerals in the body
  • Hemodialysis, or blood washing, to filter out the drugs out of the blood.
  • Laxative use to flush any unabsorbed drugs out of the body.
  • Antidote to counteract the effects of the drug and prevent serious side effects.

projectknow-shutter275473799-woman-on-ivPatients may also receive a kidney dialysis, kidney or liver transplant, and ongoing care for heart failure in case of severe naltrexone overdose symptoms. If the overdose is due to misuse and abuse of the drug, it is best to talk to a specialist to seek aftercare detox and rehab treatment. Reach out to an addiction specialist or knowledgeable physician to discuss the various treatment and recovery options available for naltrexone abuse or dependence.

Did You Know?

  • Naltrexone is an opioid receptor antagonist that can block the effects of narcotic painkillers.
  • Taking narcotics after using naltrexone may make a person more sensitive to the effects of painkillers, which may lead to adverse side effects or narcotic overdose.
  • Naltrexone has been approved by the FDA for alcohol and opioid dependence on 1984.

Was this page helpful?
Thank you for your feedback.

American Addiction Centers (AAC) is committed to delivering original, truthful, accurate, unbiased, and medically current information. We strive to create content that is clear, concise, and easy to understand.

Read our full editorial policy

While we are unable to respond to your feedback directly, we'll use this information to improve our online help.