Generic Name: methylnaltrexone (oral/injection) (METh IL nal TREX own)
Brand Name: Relistor
What is methylnaltrexone?
Methylnaltrexone blocks the effects of opioid medication. An opioid is sometimes called a narcotic.
Methylnaltrexone reduces constipation caused by using narcotic medicine for 4 weeks or longer. Methylnaltrexone works by preventing constipation without reducing the pain-relieving effects of the narcotic.
Methylnaltrexone is given to adults who use narcotic medicine to treat severe chronic pain that is not caused by cancer. Methylnaltrexone injection is also for use in adults who have advanced illness and are receiving palliative care (treatment to relieve suffering and improve quality of life during a serious illness).
Methylnaltrexone is usually given after laxatives have been tried without successful treatment of constipation.
Methylnaltrexone may also be used for purposes not listed in this medication guide.
You should not use this medicine if you have a blockage in your stomach or intestines.
Before taking this medicine
You should not use methylnaltrexone if you are allergic to it, or if you have:
a blockage in your stomach or intestines.
To make sure methylnaltrexone is safe for you, tell your doctor if you have ever had:
perforation (a hole or tear) in stomach or intestines;
liver disease; or
It is not known whether this medicine will harm an unborn baby. If you use methylnaltrexone while you are pregnant, your baby could become dependent on the drug. This can cause life-threatening withdrawal symptoms in the baby after it is born. Babies born dependent on habit-forming medicine may need medical treatment for several weeks. Tell your doctor if you are pregnant or plan to become pregnant.
It is not known whether methylnaltrexone passes into breast milk or if it could harm a nursing baby. You should not breast-feed while using this medicine.
Methylnaltrexone is not approved for use by anyone younger than 18 years old.
How should I use methylnaltrexone?
Follow all directions on your prescription label. Do not use this medicine in larger or smaller amounts or for longer than recommended.
This medicine is given daily or every other day. Do not use methylnaltrexone more often than once every 24 hours.
Methylnaltrexone can produce a bowel movement within 30 minutes. Be sure you are near a restroom when you use this medicine.
Take methylnaltrexone tablets on an empty stomach, at least 30 minutes before your first meal of the day.
Take the tablets with a full glass of water.
Methylnaltrexone injection is injected under the skin. You may be shown how to use injections at home. Do not give yourself this medicine if you do not understand how to use the injection and properly dispose of used needles and syringes. Your care provider will show you the best places on your body to inject methylnaltrexone. Use a different place each time you give an injection. Do not inject into the same place two times in a row.
Prepare your dose only when you are ready to give an injection. After loading a syringe, keep it at room temperature protected from light and use it within 24 hours. Methylnaltrexone injection should look clear or slightly yellow in color. Do not use the medication if it has changed colors or has particles in it. Call your pharmacist for new medicine.
Tell your doctor if you have any changes in weight. Methylnaltrexone injection doses are based on weight, and any changes may affect the dose.
Each single use vial (bottle) of methylnaltrexone injection is for one use only. Throw away after one use, even if there is still some medicine left in it after injecting your dose.
Use a disposable needle and syringe only once. Follow any state or local laws about throwing away used needles and syringes. Use a puncture-proof "sharps" disposal container (ask your pharmacist where to get one and how to throw it away). Keep this container out of the reach of children and pets.
Call your doctor if your symptoms do not improve after 3 days of treatment with methylnaltrexone tablets or injection.
After you stop using your pain medication, you should also stop using methylnaltrexone.
Store at room temperature away from moisture, heat, and light. Do not freeze the vials or prefilled syringes. Keep the tablets in their original container, along with the 2 canisters of moisture-absorbing preservative.
Read all patient information, medication guides, and instruction sheets provided to you. Ask your doctor or pharmacist if you have any questions.
What happens if I miss a dose?
Use the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not use extra medicine to make up the missed dose.
Do not use this medicine more than once in a 24-hour period.
What happens if I overdose?
Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.
When you have an opioid medication in your system, an overdose of methylnaltrexone could stimulate opioid withdrawal symptoms. Common withdrawal symptoms are yawning, irritability, sweating, chills, vomiting, diarrhea, and body aches.
What should I avoid while using methylnaltrexone?
Do not use any other laxatives that your doctor has not prescribed.
Methylnaltrexone side effects
Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Stop using methylnaltrexone and call your doctor at once if you have:
severe stomach pain that gets worse or will not go away;
severe or ongoing diarrhea;
extreme dizziness, or feeling like you might pass out;
bloody or tarry stools, coughing up blood or vomit that looks like coffee grounds;
nausea or vomiting that are new or worsening symptoms; or
symptoms of narcotic medicine withdrawal--anxiety, sweating, chills, yawning, stomach pain, diarrhea.
Common side effects may include:
stomach pain, gas, bloating;
mild nausea or diarrhea;
headache, muscle spasms;
dizziness, tremors, feeling anxious;
runny nose; or
chills, sweating, or hot flashes.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
See also: Side effects (in more detail)
What other drugs will affect methylnaltrexone?
Other drugs may interact with methylnaltrexone, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.
More about Relistor (methylnaltrexone)
- Side Effects
- During Pregnancy
- Dosage Information
- Drug Images
- Compare Alternatives
- Support Group
- Pricing & Coupons
- En Español
- 34 Reviews – Add your own review/rating
- Drug class: peripheral opioid receptor antagonists
- Relistor (Methylnaltrexone Injection)
- Relistor (Methylnaltrexone Tablets)
- Relistor (Advanced Reading)
- Relistor Oral (Advanced Reading)
Related treatment guides
Where can I get more information?
- Your doctor or pharmacist can provide more information about methylnaltrexone.
- Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.
- Disclaimer: Every effort has been made to ensure that the information provided by Cerner Multum, Inc. ('Multum') is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum information has been compiled for use by healthcare practitioners and consumers in the United States and therefore Multum does not warrant that uses outside of the United States are appropriate, unless specifically indicated otherwise. Multum's drug information does not endorse drugs, diagnose patients or recommend therapy. Multum's drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. Multum does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.
Copyright 1996-2012 Cerner Multum, Inc. Version: 6.02.
Date modified: March 06, 2018
Last reviewed: July 19, 2017