Methylnaltrexone Bromide (Oral)


Methylnaltrexone Bromide (Oral Route) is a medication used to treat opioid-induced constipation (OIC) caused by opioids and opioid compounds, typically taken for pain management. Methylnaltrexone Bromide should be used when patients do not respond to over-the-counter laxative medications. You should not take any other laxatives while taking this drug.

Methylnaltrexone Bromide is a mu-opioid receptor antagonist which is a type of narcotic medication that counteracts effects of opioid medications used for pain. This medication works by blocking opioid effects in the gut.

This medication is administered in pill form and taken by mouth. This medication is only available by a prescription from your healthcare professional.

If you experience any adverse reactions while taking Methylnaltrexone Bromide, you should stop taking this medication and contact your healthcare professional.

Conditions Treated

  • Patients who take opiates and opioid compounds often suffer from the side effects of constipation, which is a common problem with pain medications. Methylnaltrexone Bromide is prescribed to ease the patient's quality of life by relieving the issue of constipation.

Type Of Medicine

  • Methylnaltrexone Bromide (Oral Route) is an opioid antagonist (peripheral)

Side Effects

Along with Methylnaltrexone Bromide's desired effects, you may also experience a variety of unwanted side effects. While not everyone experiences these side effects, if they do occur, you may need to seek immediate medical attention.

Consult your doctor immediately if any of the following side effects occur after administering Methylnaltrexone Bromide:

  • Anxiety or fear
  • Sweating
  • Excessive Diarrhea
  • Excessive yawning
  • Severe abdominal pain
  • Chills
  • Bloody or black stools
  • Coughing blood

Some side effects may occur that are less serious and do not require medical attention. The following side effects may disappear during the course of treatment with this drug as your body adjusts to the medication. Consult with your health care professional if any of the less common side effects continue for an extended period of time:

  • Bloated feeling
  • Stomach pressure
  • Headache
  • Unusual nausea or vomiting
  • Swelling of the stomach
  • Runny nose
  • Muscle spasms
  • Lightheadedness
  • Gas
  • Shaking or tremors

Your health care professional may be able to advise you on how to reduce some of these side effects.


Methylnaltrexone Bromide (Oral Route) comes in the form of pills to be taken by mouth. Read and follow the instructions in the guide that came with this medication.

Follow the directions given by your doctor and on your prescription label carefully and if you have any questions, ask your healthcare provider or pharmacist. Do not use more or less of this medication than prescribed and do not take it longer than required. Taking more of this medication than necessary can increase the chance of side effects.

Once you have stopped taking the opioids that cause constipation, you should also stop taking this medication.

This medication should be taken on an empty stomach, at least 30 minutes before you have your first meal. Always take this medication with 8 ounces of water.

The amount of Methylnaltrexone Bromide you take will depend on the strength prescribed to you. Be sure to check the label on your medication to ensure the number of doses, the time period between doses, and how long you should take this medication is what your doctor prescribed for your condition. Depending on your condition, your dosage may be different than those listed here.

To relieve constipation due to the usage of opioids for non-cancer pain:

  • Adults take 450 milligrams once a day, in the morning 30 minutes prior to your first meal
  • Children's dosages vary and need to be directed by your healthcare professional

This medication can start working within 30 minutes of taking it, so be sure to be near a restroom after you take it.

If you miss a dose, take the missed dose as soon as you remember. However, if it is almost time for your next dose, wait for that dose. Do not use double the amount for a missed dose.

If you take more Methylnaltrexone Bromide than prescribed, you should be monitored by your doctor as you could experience withdrawal symptoms from any opioids you are taking. Symptoms could include diaphoresis, chills, or rhinorrhea.

Follow the directions given by your doctor and on your prescription label carefully and if you have any questions, ask your healthcare provider or pharmacist. Do not use more or less of this medication than prescribed.


Some medications should not be used together, however, sometimes two medications may be used together even if there is the possibility of an interaction. Your doctor can adjust your dosages in the case you are taking two medications known to interact.

Be sure your health care professional knows if you are taking any of the medications below.

Do not take this medication with over-the-counter laxatives. Stop using any laxatives before starting this medicine.

Methylnaltrexone Bromide may interact with the following medications:

  • Prescription laxatives
  • Over-the-counter laxatives
  • Buprenorphine
  • Butorphanol
  • Codeine
  • Hydrocodone
  • Hydromorphone
  • Levorphanol
  • Methadone
  • Meperidine
  • Morphine
  • Nalbuphine
  • Naloxone
  • Oxycodone
  • Oxymorphone
  • Propoxyphene

If you are pregnant or plan on becoming pregnant while taking this medication, be sure to tell your doctor. Also, consult your doctor if you are breastfeeding as it is not known how this medicine effect breast milk.

Always tell your doctor about any prescription or non-prescription (over-the-counter) medications you are taking, including supplements and vitamins.

It is not recommended to take Methylnaltrexone Bromide with the following medications unless your doctor prescribes them together:

  • Buprenorphine
  • Morphine
  • Morphine Sulfate Liposome
  • Naloxegol
  • Oxycodone
  • Oxymorphone

Some medications can interact with some types of foods, alcohol or tobacco. Be sure to discuss use of certain foods, alcohol or tobacco with your health care professional before taking this medication.


Your health care professional should examine your progress while you are taking this medicine to determine if it is working for your condition.

Patients with a stomach or bowel blockage should not use Methylnaltrexone Bromide. If you have any stomach issues you should inform your healthcare professional.

Methylnaltrexone Bromide could cause perforations in the bowels or stomach. If you experience continual or severe abdominal or stomach pain, contact your doctor immediately.

Also, contact your doctor if you experience severe diarrhea while taking this medication.

If you decide to use this medication, the risks of taking it should be weighed against the benefits to your condition. You should discuss the risks of taking this medication with your healthcare professional. When taking Methylnaltrexone Bromide, you should consider the following:

Additional Medical Problems: Be sure to contact your healthcare professional if you have medical problems other than those for which you are taking this medication, such as

Allergies Inform your health care professional if you have any allergies to this or any other medication or any of the ingredients in this medication. Also tell your doctor if you have certain allergies to foods, preservatives, animals or dyes. If you are allergic to this medication, you should not use it.

Pregnancy: There are no studies that give adequate information as to how this medication effects pregnant women or women who are breastfeeding. If you use Methylnaltrexone Bromide while pregnant, there is the possibility your baby could experience dependency on this drug which can cause withdrawal symptoms once your baby is born. Tell your doctor if you are pregnant before taking this medication.

Pediatric Safety and efficacy for this medication have not been determined for pediatric patients. Consult your doctor before giving Methylnaltrexone Bromide to pediatric patients.

Geriatric No studies to date have shown any particular problems with geriatric patients when using Methylnaltrexone Bromide. Geriatric patients may experience side effects such as diarrhea when taking this medication. Your doctor will determine appropriate dosages for elderly patients.

You should not stop taking this medication suddenly without consulting your doctor first. If you suddenly stop taking this medication, you could experience diarrhea, irritability, stomach pain, sweating, anxiety, chills, or excessive yawning.


Keep this and all medications out of the reach of children.

Methylnaltrexone Bromide tablets should be stored at temperatures up to 77 F (25 C) with ranges from 59 F to 86 F. This medication should not be stored in excessive heat or freezing temperatures. This medication should be kept away from the light.

This medication should be stored in a closed container.

Do not keep medication longer than needed. If this medication is expired, discard it appropriately. Do not throw away or flush this medication. To dispose of this medication properly, speak to your pharmacist or physician about the FDA's Safe Disposal of Medicines program for more information on how to discard this and other medications.


Methylnaltrexone Bromide was prescribed by your healthcare professional to relieve symptoms of constipation due to opioid usage.

When taking this medication, be sure to be near a restroom as it starts working within 30 minutes of your first dose.

This medication should be taken once per day in the morning prior to your first meal. Take this medicine with water. Your doctor may prescribe a different dosage of this medication, so be sure to read the label carefully.

Contact your doctor if you experience any severe side effects such as unusual nausea or vomiting, swelling in the stomach, muscle spasms or any other side effects listed here.

It is not clear how Methylnaltrexone Bromide will affect women who are pregnant, trying to become pregnant or breastfeeding, so be sure to tell your doctor if you have any of these conditions. Also be sure to tell your doctor of any over-the-counter or prescription medications or dietary supplements you are currently taking as they may cause an adverse reaction while taking this drug.

Do not take more or less of this medication than prescribed by your healthcare professional.

If you have any questions or concerns about Methylnaltrexone Bromide or its side effects, consult your health care professional immediately