Naltrexone (By mouth)


Naltrexone (nal-TREX-one)
Helps former drug users stay off of drugs. Also helps patients with alcohol problems by keeping the body from wanting alcohol. This medicine does not take the place of active involvement in a recovery program.

Brand Name(s)

There may be other brand names for this medicine.


When This Medicine Should Not Be Used

You should not use this medicine if you have used heroin or taken narcotic drugs (such as codeine or other strong habit-forming pain killers) within the past 7 to 10 days.

How to Use This Medicine

  • Your doctor will tell you how much medicine to take and how often. Ask if you don't understand what the doctor tells you.
  • Drink plenty of fluids to help avoid constipation.
  • It is important for you to be with people who can give you support to stay off drugs or alcohol. There are many groups that can help you do this. Talk to your caregiver about this if you are new in recovery.
If a dose is missed:
  • Take the missed dose as soon as possible, unless it is almost time for your next dose.
  • Skip the missed dose if it is almost time for your next usual dose.
  • You should not use two doses at the same time.

How to Store and Dispose of This Medicine

  • Store the medicine at room temperature, away from heat, moisture, and direct light.
  • Keep all medicine out of the reach of children.

Drugs and Foods to Avoid

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.
  • This medicine blocks the "high" feeling you get from narcotic drugs and heroin. You should not use large amounts of heroin or narcotic drugs to overcome what the medicine is supposed to do. You could overdose and go into a coma or die.
  • Naltrexone may keep some medicines from working. If you need medicine for pain, diarrhea, or a cold ask your doctor or pharmacist what is best for you to take.

Warnings While Using This Medicine

  • You may need to carry a card to let others know you are taking this medicine if you have a medical emergency. Ask your doctor about this.
  • Any time you need medical care, tell your doctor or other caregiver that you are taking naltrexone.
  • Make sure your doctor knows if you have liver disease or hepatitis before you take naltrexone.
  • If you are pregnant or breastfeeding, talk to your doctor before you take this medicine.
  • Your doctor may want you to have blood tests while you are taking naltrexone. Keep your appointments at the clinic or doctor's office.
  • This medicine may cause constipation. This is more common if you use it for a long time. Ask your doctor if you should also use a laxative to prevent and treat constipation.

Possible Side Effects While Using This Medicine

Call your doctor right away if you notice any of these side effects:
  • Severe stomach pain
  • Yellowing of your skin or eyes
  • Dark-colored urine
If you notice these less serious side effects, talk with your doctor:
  • Trouble sleeping
  • Nervousness
  • Mild stomach pain or cramps, nausea, or vomiting
  • Headache
  • Diarrhea or constipation
  • Joint or muscle pain

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088
Review Date: 2011-02-04 Reviewed By: Keywords: ,
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