Is Relistor (methylnaltrexone) a narcotic?

Relistor (methylnaltrexone) isn't a narcotic or controlled substance, since it doesn't have potential for abuse. Relistor (methylnaltrexone) is used to treat constipation that is due to use of opioids, which are narcotic pain medications.

How should I take Relistor (methylnaltrexone)?

If you're taking the oral form of Relistor (methylnaltrexone), you'll want to take it with water on an empty stomach at least 30 minutes before your first meal of the day. If you're using the injectable form, you can give the Relistor (methylnaltrexone) injection under the skin of the upper arm, abdomen (belly area), or thigh. Make sure to change where you inject each time. Ask your provider or pharmacist to show you how to inject the medication correctly.

Relistor

methylnaltrexone

Used for Constipation

Relistor (methylnaltrexone) is a good oral or injectable option for treating constipation due to opioid pain medications, but it can cause opioid withdrawal symptoms and diarrhea, and is quite expensive if it's not covered by insurance.

Reviewed by:

Aileen Chu, PharmD, BCPS

Allison Gourley, PharmD

Last reviewed on August 16, 2021

What is Relistor (methylnaltrexone)?

What is Relistor (methylnaltrexone) used for?

Constipation due to opioid pain medications

How Relistor (methylnaltrexone) works

Opioid medications cause constipation because they slow down movement in the intestines (gut). Relistor (methylnaltrexone) is an opioid antagonist, which means that it blocks the opioid receptors in the intestines so that you can go to the bathroom more easily.

Drug facts

Common BrandsRelistor

Drug ClassOpioid antagonist

Controlled Substance ClassificationNot a controlled medication

Generic StatusNo lower-cost generic available

AvailabilityPrescription only

Side effects of Relistor (methylnaltrexone)

The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.

Common Side Effects

Abdominal pain (14-29%)
Diarrhea (5-6%)
Nausea (9-12%) - mainly with injection form

Less Common Side Effects

Headache
Abdominal distention (feeling bloated)
Vomiting
Sweating
Anxiety
Muscle spasms
Runny nose
Chills
Hot flash
Tremor
Dizziness

Relistor (methylnaltrexone) serious side effects

Contact your healthcare provider immediately if you experience any of the following.

Severe abdominal pain, which may be a symptom of stomach or intestine injury
Severe diarrhea

Source: FDA

The following Relistor (methylnaltrexone) side effects have also been reported

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

More common

Diarrhea

increased sweating

Incidence not known

Bloody, black, or tarry stools

heartburn

indigestion

nausea

severe abdominal or stomach pain, cramping, or burning

trouble breathing

vomiting of material that looks like coffee grounds, severe and continuous

Get emergency help immediately if any of the following symptoms of overdose occur:

Symptoms of overdose

Chills

cold sweats

confusion

dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

Bloated

dizziness

excess air or gas in the stomach or intestines

feeling of fullness

passing of gas

stomach pain

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

See more Relistor (methylnaltrexone) side effects

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Pros and cons of Relistor (methylnaltrexone)

Pros

Improves your chances of having bowel movements while you're on opioid medications
Available in injection form if you're unable to take medications by mouth or if you have an advanced illness
Injection form works pretty quickly (about 4 hours)
Directly targets the receptors that are causing constipation

Cons

Usually reserved for more severe constipation, after you have tried other medications first
Oral form must be taken daily, cannot be used "as needed"
Abdominal pain, diarrhea, and nausea are fairly common side effects.
Brand-name only and may be very expensive

Pharmacist tips for Relistor (methylnaltrexone)

Relistor (methylnaltrexone) pills are only approved for people taking opioid medications for pain that's not due to cancer. If you are taking opioid medications for cancer-related pain, you'll need to use the injection form of Relistor (methylnaltrexone).
If you're using opioids for non-cancer-related pain, stop taking all laxatives before starting on Relistor (methylnaltrexone). You can start using laxatives again if you're still constipated after using this medication for 3 days. Let your provider know if you change your opioid dose, since you may be more likely to get side effects like diarrhea.
If you're using the pill form, take it with water on an empty stomach at least 30 minutes before breakfast. If you take Relistor (methylnaltrexone) with food, it won't absorb in your body or work as well.
If you're using the injection form, make sure that your provider or pharmacist has shown you the proper injection technique. You'll want to inject Relistor (methylnaltrexone) into the upper arm, abdomen (belly area), or thigh. Rotate injection sites so that you're not using the same spot over and over again. Afterwards, make sure to throw out your needle in an appropriate disposal container, not the trash.
If you're using the injection form, make sure you're near a toilet after taking Relistor (methylnaltrexone), since it can make you have a bowel movement pretty quickly.
Stop taking Relistor (methylnaltrexone) if you stop taking opioid medications. If you continue to have constipation after you stop taking opioids, you'll need to use something else to treat it because Relistor (methylnaltrexone) will no longer be helpful.
Talk to your provider if you are pregnant or planning to become pregnant. Relistor (methylnaltrexone) can cause opioid withdrawal, which can be stressful to you and your unborn baby.
Relistor (methylnaltrexone) is brand-name only and may be expensive, even if you have insurance. Talk to your provider or pharmacist to see if you are eligible for a savings coupon.

Common questions about Relistor

After getting a Relistor injection, you can expect to have a bowel movement within 4 hours. Some people may even be able to have a bowel movement 30 minutes after the dose, which is why they tell you to make sure that you're near a toilet after taking this medication. Relistor doesn't work quickly for everyone, however, so you may have to take laxatives if you don't have success after 4 hours. The oral form of Relistor doesn't work as reliably or quickly, but taking it every day will help you have more bowel movements per week. If you haven't had a bowel movement after taking the oral form for 3 days, you may need to take laxatives along with Relistor.

Relistor helps with laxation, which is the medical term for having a bowel movement. Unlike traditional laxatives, which are typically helpful for constipation due to various causes, Relistor only works for constipation due to opioid pain medications because it targets opioid receptors in the intestines. So for people who have constipation due to opioids, it has a similar effect as traditional laxatives because it gets your intestines moving again. If Relistor doesn't work well enough, you can continue to take laxatives like Dulcolax (bisacodyl) or enemas to help with your constipation.

Relistor isn't a narcotic or controlled substance, since it doesn't have potential for abuse. Relistor is used to treat constipation that is due to use of opioids, which are narcotic pain medications.

If you are using Relistor to treat opioid-related constipation and you don't have cancer, you should take this medication once daily. Specifically, you'll want to take 450 mg by mouth every morning before breakfast, or inject 12 mg once daily, in order to have more regular bowel movements. If you or a loved one are using Relistor because of cancer or advanced illness such as severe lung disease, AIDS, or dementia, then Relistor should be used every other day as needed for constipation, but no more than 1 dose in a 24-hour period.

If you're taking the oral form of Relistor, you'll want to take it with water on an empty stomach at least 30 minutes before your first meal of the day. If you're using the injectable form, you can give the Relistor injection under the skin of the upper arm, abdomen (belly area), or thigh. Make sure to change where you inject each time. Ask your provider or pharmacist to show you how to inject the medication correctly.

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Risks and warnings for Relistor (methylnaltrexone)

Relistor (methylnaltrexone) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.

Gastrointestinal (stomach or intestinal) injury

Risk factors: Gastrointestinal disease or inflammation

In some rare cases, Relistor (methylnaltrexone) can cause gastrointestinal injury, including a hole or tear in the stomach or intestines which can be life-threatening. If you already have gastrointestinal problems, such as cancer, ulcer, inflammation, or Crohn's disease, talk to your provider about the risks and benefits before starting Relistor (methylnaltrexone). If you experience worsening, severe abdominal pain that doesn't go away, stop taking Relistor (methylnaltrexone) and contact your provider right away.

Diarrhea

Relistor (methylnaltrexone) can cause severe diarrhea that doesn't go away. This could cause you to become dehydrated, which could be very dangerous. If you have several loose, watery stools, stop taking Relistor (methylnaltrexone) and talk to your provider.

Opioid withdrawal

Relistor (methylnaltrexone) can cause opioid withdrawal symptoms (sweating, chills, diarrhea, abdominal pain, anxiety, irritability, and yawning). In some rare cases, you may also get less pain relief from opioid medications. Talk to your provider if you experience any withdrawal symptoms or if your pain medications aren't working as well anymore.

Relistor (methylnaltrexone) dosage

The average cost for 90 tablets of 150mg of Relistor (methylnaltrexone) is $2,293.21 with a free GoodRx coupon. This is 30.56% off the average retail price of $3,302.38.

Syringe

Dosage	Quantity	Price as low as	Price per unit
0.6ml of 12mg/0.6ml	3 syringes	$468.14	$156.05
0.4ml of 8mg/0.4ml	2 syringes	$316.63	$158.32

Tablet

Dosage	Quantity	Price as low as	Price per unit
150mg	90 tablets	$2,293.21	$25.48

See more Relistor (methylnaltrexone) dosage

Interactions between Relistor (methylnaltrexone) and other drugs

Relistor (methylnaltrexone) may interact with certain medications or supplements. Always let your doctor and pharmacist know about any other medications or supplements (including prescribed and over-the-counter medications, vitamins, and dietary or herbal supplements) that you are currently taking. The list below does not include all possible drug interactions with Relistor (methylnaltrexone). Please note that only the generic name of each medication is listed below.

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.