Methylnaltrexone

Pediatric Medication
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This information from Lexicomp® explains what you need to know about this medication, including what it’s used for, how to take it, its side effects, and when to call your healthcare provider.

Brand Names: US

Relistor

Brand Names: Canada

Relistor

What is this drug used for?

  • It is used to treat constipation caused by some pain drugs.
  • This drug is not approved for use in children. However, the doctor may decide the benefits of taking this drug outweigh the risks. If your child has been given this drug, ask the doctor for information about the benefits and risks. Talk with the doctor if you have questions about giving this drug to your child.

What do I need to tell the doctor BEFORE my child takes this drug?

  • If your child is allergic to this drug; any part of this drug; or any other drugs, foods, or substances. Tell the doctor about the allergy and what signs your child had.
  • If your child has a bowel blockage or a raised risk for bowel blockage.
  • If your child is using another drug like this one. If you are not sure, ask your child’s doctor or pharmacist.

If your child is breast-feeding a baby:

  • Be sure your child does not breast-feed a baby while taking this drug.

This is not a list of all drugs or health problems that interact with this drug.

Tell the doctor and pharmacist about all of your child’s drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe to give this drug with all of your child’s other drugs and health problems. Do not start, stop, or change the dose of any drug your child takes without checking with the doctor.

What are some things I need to know or do while my child takes this drug?

  • Tell all of your child’s health care providers that your child is taking this drug. This includes your child’s doctors, nurses, pharmacists, and dentists.
  • Be sure to have your child stay close to a bathroom after using this drug. Most people have a stool within a few minutes to a few hours after using it.
  • Talk with your child’s doctor before giving your child a laxative with this drug.
  • This drug is only for use in patients who take opioid pain drugs. Tell your child’s doctor if your child stops taking the pain drug.
  • Signs of opioid withdrawal have happened with this drug. Call your child’s doctor right away if your child has sweating, chills, abnormal diarrhea or stomach pain, anxiety, feeling irritable, or yawning.
  • This drug may not work as well for people who have been taking pain drugs for less than 4 weeks.

If your child is pregnant:

  • Tell the doctor if your child is pregnant or becomes pregnant. You will need to talk about the benefits and risks of your child using this drug while pregnant.
  • If this drug is used during pregnancy, it may cause withdrawal in the unborn baby. A doctor will need to check on the unborn baby after this drug is used.

What are some side effects that I need to call my child’s 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 child’s doctor or get medical help right away if your child has 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.
  • Chills.
  • Shakiness.
  • Swelling of belly.
  • Tears in the stomach or bowel wall have happened in certain people taking this drug. Call your child’s doctor right away if your child has swelling or pain in the stomach that is very bad, gets worse, or does not go away. Call your child’s doctor right away if your child throws up blood or has 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 this drug?

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

  • Stomach pain.
  • Sweating a lot.
  • Upset stomach or throwing up.
  • Gas.
  • Dizziness.
  • Flushing.
  • Diarrhea may happen with this drug and can be severe. Call your child’s doctor to find out what to do if your child has severe or long-lasting diarrhea.

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

You may report side effects to your national health agency.

How is this drug best given?

Give this drug as ordered by your child’s doctor. Read all information given to you. Follow all instructions closely.

Injection:

  • It is given as a shot into the fatty part of the skin on the top of the thigh, belly area, or upper arm.
  • If you will be giving your child the shot, your child’s doctor or nurse will teach you how to give the shot.
  • Wash your hands before and after use.
  • Move the site where you give the shot with each shot.
  • Do not give into skin that is irritated, tender, bruised, red, scaly, hard, scarred, or has stretch marks.
  • Do not use if the solution is cloudy, leaking, or has particles.
  • This drug is colorless to a faint yellow. Do not use if the solution changes color.
  • Each prefilled syringe or vial is for one use only. Throw away any part left over after the dose is given.
  • Throw away needles in a needle/sharp disposal box. Do not reuse needles or other items. When the box is full, follow all local rules for getting rid of it. Talk with a doctor or pharmacist if you have any questions.

Vials:

  • If this drug is drawn from a vial into a syringe, it may be stored in the syringe at room temperature for up to 24 hours.

What do I do if my child misses a dose?

  • If your child uses this drug on a regular basis, give a missed dose as soon as you think about it.
  • If it is close to the time for your child’s next dose, skip the missed dose and go back to your child’s normal time.
  • Do not give 2 doses at the same time or extra doses.
  • Many times this drug is given on an as needed basis. Do not give to your child more often than told by the doctor.

How do I store and/or throw out this drug?

  • Store at room temperature protected from light. Store in a dry place. Do not store in a bathroom.
  • Do not freeze.
  • 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.

General drug facts

  • If your child’s symptoms or health problems do not get better or if they become worse, call your child’s doctor.
  • Do not share your child’s drug with others and do not give anyone else’s drug to your child.
  • Some drugs may have another patient information leaflet. If you have any questions about this drug, please talk with your child’s doctor, nurse, 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.

Consumer Information Use and Disclaimer

This generalized information is a limited summary of diagnosis, treatment, and/or medication information. It is not meant to be comprehensive and should be used as a tool to help the user understand and/or assess potential diagnostic and treatment options. It does NOT include all information about conditions, treatments, medications, side effects, or risks that may apply to a specific patient. It is not intended to be medical advice or a substitute for the medical advice, diagnosis, or treatment of a health care provider based on the health care provider’s examination and assessment of a patient’s specific and unique circumstances. Patients must speak with a health care provider for complete information about their health, medical questions, and treatment options, including any risks or benefits regarding use of medications. This information does not endorse any treatments or medications as safe, effective, or approved for treating a specific patient. UpToDate, Inc. and its affiliates disclaim any warranty or liability relating to this information or the use thereof. The use of this information is governed by the Terms of Use, available at https://www.wolterskluwer.com/en/know/clinical-effectiveness-terms.

Last Reviewed Date

2024-09-23

Copyright

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Last Updated

Thursday, September 26, 2024