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Relistor Tablets

Generic name: Methylnaltrexone Tabletsmeth-il-nal-TREKS-one ]
Drug class: Peripheral opioid receptor antagonists

Medically reviewed by Last updated on Oct 22, 2022.

Uses of Relistor:

What do I need to tell my doctor BEFORE I take Relistor?

  • If you have an allergy to methylnaltrexone or any other part of Relistor (methylnaltrexone tablets).
  • If you are allergic to Relistor (methylnaltrexone tablets); any part of Relistor (methylnaltrexone tablets); or any other drugs, foods, or substances. Tell your doctor about the allergy and what signs you had.
  • If you have ever had bowel block.
  • If you are taking or will be taking another drug like this one.
  • If you are breast-feeding. Do not breast-feed while you take Relistor (methylnaltrexone tablets).

This is not a list of all drugs or health problems that interact with Relistor (methylnaltrexone tablets).

Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take Relistor (methylnaltrexone tablets) with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.

What are some things I need to know or do while I take Relistor?

  • Tell all of your health care providers that you take Relistor (methylnaltrexone tablets). This includes your doctors, nurses, pharmacists, and dentists.
  • Be sure to stay close to a bathroom after you use Relistor (methylnaltrexone tablets). Most people have a stool within a few minutes to a few hours after using it.
  • Talk with your doctor before using a laxative with Relistor (methylnaltrexone tablets).
  • This medicine is only for use in patients who take pain drugs. Tell your doctor if you stop taking your pain drug.
  • Signs of opioid withdrawal have happened with Relistor (methylnaltrexone tablets). Call your doctor right away if you have more sweating, chills, diarrhea or stomach pain that is not normal, anxiety, feeling irritable, or yawning.
  • This medicine may not work as well for people who have been taking pain drugs for less than 4 weeks.
  • If you are 65 or older, use Relistor (methylnaltrexone tablets) with care. You could have more side effects.
  • Tell your doctor if you are pregnant or plan on getting pregnant. You will need to talk about the benefits and risks of using Relistor (methylnaltrexone tablets) while you are pregnant.
  • If Relistor (methylnaltrexone tablets) is used during pregnancy, it may cause withdrawal in the unborn baby. A doctor will need to check on the unborn baby after Relistor (methylnaltrexone tablets) is used.

How is this medicine (Relistor) best taken?

Use Relistor (methylnaltrexone tablets) as ordered by your doctor. Read all information given to you. Follow all instructions closely.

  • Take on an empty stomach. Take at least 30 minutes before the first meal of the day.
  • Take with a full glass of water.

What do I do if I miss a dose?

  • If you take Relistor (methylnaltrexone tablets) on a regular basis, take a missed dose as soon as you think about it.
  • If it is close to the time for your next dose, skip the missed dose and go back to your normal time.
  • Do not take 2 doses at the same time or extra doses.
  • Many times Relistor (methylnaltrexone tablets) is taken on an as needed basis. Do not take more often than told by the doctor.

What are some side effects that I need to call my doctor about right away?

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

  • Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
  • Severe diarrhea.
  • Diarrhea that will not go away.
  • Chills.
  • Shakiness.
  • Tears in the stomach or bowel wall have happened in certain people taking Relistor (methylnaltrexone tablets). Call your doctor right away if you have swelling or pain in your stomach that is very bad, gets worse, or does not go away. Call your doctor right away if you throw up blood or have throw up that looks like coffee grounds; upset stomach or throwing up that does not go away; or black, tarry, or bloody stools.

What are some other side effects of Relistor?

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.

You may report side effects to the FDA at 1-800-332-1088. You may also report side effects at

If OVERDOSE is suspected:

If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

How do I store and/or throw out Relistor?

  • Store at room temperature.
  • Store in a dry place. Do not store in a bathroom.
  • Keep all drugs in a safe place. Keep all drugs out of the reach of children and pets.
  • Throw away unused or expired drugs. Do not flush down a toilet or pour down a drain unless you are told to do so. Check with your pharmacist if you have questions about the best way to throw out drugs. There may be drug take-back programs in your area.
  • Store in the original container. Do not take out the antimoisture cube or packet.

Consumer Information Use and Disclaimer

  • If your symptoms or health problems do not get better or if they become worse, call your doctor.
  • Do not share your drugs with others and do not take anyone else's drugs.
  • This medicine comes with an extra patient fact sheet called a Medication Guide. Read it with care. Read it again each time Relistor (methylnaltrexone tablets) is refilled. If you have any questions about Relistor (methylnaltrexone tablets), please talk with the doctor, pharmacist, or other health care provider.
  • If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.