Drug Database - Naltrexone

Generic Name: Naltrexone (nal-TREX-ohn)

Brand Names: Revia®

Classification: Opioid Receptor Antagonist

Naltrexone for Fibromyalgia:

A Standford University pilot study tested Naltrexone on 10 women with fibromyalgia. Naltrexone appeared to improve pain thresholds (the point at which sensation becomes pain) and lower overall symptoms. Stanford is now preparing larger studies on Naltrexone for fibromyalgia (in adults) and juvenile fibromyalgia.

While this is the first study of LDN for fibromyalgia, the drug has been prescribed off-label for several years.

Naltrexone for Chronic Fatigue Syndrome:

So far, Naltrexone has not been studied for chronic fatigue syndrome. However, some doctors and patients say they've used Naltrexone successfully. As with fibromyalgia, Naltrexone is sometimes prescribed off-label for chronic fatigue syndrome.

Some medical conditions may interact with Naltrexone. Tell your doctor or pharmacist if you have any medical conditions, especially if any of the following apply to you:

• if you are pregnant, planning to become pregnant, or are breast-feeding
• if you are taking any prescription or nonprescription medicine, herbal preparation, or dietary supplement
• if you have allergies to medicines, foods, or other substances
• if you have kidney or liver problems
• if you have a history of suicidal thoughts or behavior with or without depression

Some MEDICINES MAY INTERACT with Naltrexone. Tell your health care provider if you are taking any other medicines, especially any of the following:

• Narcotic analgesics, narcotic cough/cold medicines, or medicines used for diarrhea.
• Thioridazine because side effects such as sleepiness and sluggishness may occur

This may not be a complete list of all interactions that may occur. Ask your health care provider if Naltrexone may interact with other medicines that you take. Check with your health care provider before you start, stop, or change the dose of any medicine.

Use Naltrexone as directed by your doctor. Check the label on the medicine for exact dosing instructions.

• Naltrexone may be taken with or without food.


• Naltrexone should not be taken until the naltrexone challenge test is negative.


• Before taking Naltrexone, you must be willing to take Naltrexone to help with alcohol dependence, you must be free of substance abuse for 7 to 10 days, you must not have any severe or active liver or kidney problems, and you must not have any other medical problems or conditions that make taking Naltrexone inadvisable.


• If you miss a dose of Naltrexone and you are taking 1 dose daily, do no try to make up the missed dose by doubling the dose the next day. Take the next scheduled dose and consult your doctor.

Ask your health care provider any questions you may have about how to use Naltrexone.

Naltrexone may cause dizziness or drowsiness. Do not drive, operate machinery, or do anything else that could be dangerous until you know how you react to Naltrexone. Using Naltrexone alone, with other medicines, or with alcohol may lessen your ability to drive or to perform other potentially dangerous tasks.

Carry identification to alert health care providers that you are taking Naltrexone. You can get a medication card from your doctor to use for this purpose.

Before you have any medical or dental treatments, emergency care, or surgery, tell the doctor or dentist that you are using Naltrexone.

Contact your health care provider at once if any of the following signs or symptoms of hepatitis occur while taking Naltrexone:

• stomach pain lasting more than a few days
• white bowel movements
• dark urine
• yellowing of the skin or eyes

Do not use narcotics while taking Naltrexone, including opioid-containing medicines (eg, cough and cold products, pain relievers, heroin). Naltrexone may increase your sensitivity to narcotics. Therefore, even very low doses may cause coma or be life-threatening.

Before you have any medical or dental surgery or emergency treatments, tell the doctor or dentist that you are taking Naltrexone.

Lab tests, including liver function, may be performed to monitor your progress or to check for side effects. Be sure to keep all doctor and lab appointments.

Use Naltrexone with extreme caution in CHILDREN younger than 18 years of age. Safety and effectiveness in this age group have not been confirmed.

PREGNANCY and BREAST-FEEDING: If you become pregnant, discuss with your doctor the benefits and risks of using Naltrexone during pregnancy. It is unknown if Naltrexone is excreted in breast milk. If you are or will be breast-feeding while you are using Naltrexone, check with your doctor or pharmacist to discuss the risks to your baby.

If you are addicted to narcotics and are given Naltrexone, you may experience WITHDRAWAL symptoms include:

• anxiety
• diarrhea
• fever, runny nose or sneezing
• goose bumps and abnormal skin sensations
• nausea
• vomiting
• pain
• rigid muscles
• rapid heartbeat
• seeing, hearing, or feeling things that are not there
• shivering or tremors
• sweating
• trouble sleeping

Contact 1-800-222-1222 (the American Association of Poison Control Centers), your local poison control center (http://www.aapcc.org), or emergency room immediately.

Side Effects

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome:

• anxiety
• appetite loss
• chills; constipation
• delayed ejaculation
• diarrhea; dizziness
• drowsiness
• feeling down
• headache
• increased energy
• increased thirst
• irritability
• joint and muscle pain
• low energy
• nausea
• nervousness
• sleeplessness
• stomach pain/cramps
• vomiting

Seek medical attention right away if any of these SEVERE side effects occur:

• Severe allergic reactions
• rash
• hives
• itching
• difficulty breathing
• tightness in the chest
• swelling of the mouth, face, lips, or tongue
• abdominal or stomach pain
• cramping
• dark urine
• depression
• suicidal thoughts or behaviors
• unusual tiredness or weakness
• vomiting
• white bowel movements
• yellowing of the skin or eyes

This is not a complete list of all side effects that may occur. If you have questions about side effects, contact your health care provider. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088. You may also report side effects at http://www.fda.gov/medwatch.

Studies to evaluate possible interactions between Naltrexone and drugs other than opiates have not been performed. Consequently, caution is advised if the concomitant administration of Naltrexone and other drugs is required.

The safety and efficacy of concomitant use of Naltrexone and disulfiram is unknown, and the concomitant use of two potentially hepatotoxic medications is not ordinarily recommended unless the probable benefits outweigh the known risks.

Lethargy and somnolence have been reported following doses of Naltrexone and thioridazine.

Patients taking Naltrexone may not benefit from opioid containing medicines, such as cough and cold preparations, antidiarrheal preparations, and opioid analgesics. In an emergency situation when opioid analgesia must be administered to a patient receiving Naltrexone, the amount of opioid required may be greater than usual, and the resulting respiratory depression may be deeper and more prolonged