Generic Name: methylnaltrexone (oral/injection) (METh IL nal TREX own)
Brand Names: Relistor
Medically reviewed on Sep 4, 2017
What is Relistor?
Relistor (methylnaltrexone) blocks the effects of opioid medication. An opioid is sometimes called a narcotic.
Relistor 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.
Relistor is given to adults who use narcotic medicine to treat severe chronic pain that is not caused by cancer.
Relistor 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).
This medicine is usually given after laxatives have been tried without successful treatment of constipation.
You should not use Relistor if you have a blockage in your stomach or intestines.
Before you use Relistor, tell your doctor if you have severe or ongoing diarrhea.
Prepare your dose in a syringe only when you are ready to give yourself an injection. After loading a syringe, if you cannot give the injection right away keep it at room temperature and use it within 24 hours.
Before using this medicine
You should not use Relistor if you are allergic to methylnaltrexone, or if you have:
a blockage in your stomach or intestines.
To make sure Relistor is safe for you, tell your doctor if you have ever had:
a stomach ulcer;
a perforation (hole or tear) in stomach or intestines;
kidney disease; or
colitis or other intestinal disorder such as Crohn's disease, diverticulitis, or Ogilvie's syndrome.
It is not known whether Relistor will harm an unborn baby. If you use this medicine 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.
Relistor is not approved for use by anyone younger than 18 years old.
How should I use Relistor?
Relistor is injected under the skin. 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 Relistor more often than once every 24 hours.
Relistor can produce a bowel movement within 30 minutes. Be sure you are near a restroom when you use this medicine.
Take the 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.
Relistor injection is injected under the skin. You may be shown how to use injections at home. Do not self inject this medicine if you do not understand how to give the injection and properly dispose of used needles and syringes. Your care provider will show you the best places on your body to inject Relistor. 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. Relistor 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. Injection doses are based on weight, and any changes may affect the dose.
Each single use vial (bottle) of Relistor 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 Relistor tablets or injection.
After you stop using your pain medication, you should also stop using this medicine.
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.
Relistor dosing information
Usual Adult Dose for Constipation - Chronic:
Opioid-Induced Constipation in Patients with Chronic Non-Cancer Pain:
12 mg subcutaneously once a day
Comments: Prior to initiation, discontinue all maintenance laxative therapy; laxatives can be used as needed for suboptimal response after 3 days.
Opioid-Induced Constipation in Patients with Advanced Illness:
-One-dose subcutaneously every other day as needed, but no more frequently than 1 dose in a 24-hour period; weight-based dosing as follows:
Less than 38 kg: 0.15 mg/kg
38 kg to less than 62 kg: 8 mg (0.4 mL)
62 kg to 114 kg: 12 mg subcutaneously (0.6 mL)
More than 114 kg: 0.15 mg/kg subcutaneously
Comments: To determine injection volume for patients whose weight is less than 38 kg or more than 114 kg: multiply patient weight (kg) by 0.0075 and round up to the nearest 0.1 mL
-For the treatment of opioid-induced constipation in adult patients with chronic non-cancer pain.
-For the treatment of opioid-induced constipation in adult patients with advanced illness who are receiving palliative care, when response to laxative therapy has not been sufficient.
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 Relistor?
Do not use any other laxatives that your doctor has not prescribed.
Relistor side effects
Get emergency medical help if you have signs of an allergic reaction to Relistor: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Stop using Relistor 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 Relistor 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.
What other drugs will affect Relistor?
Other drugs may interact with methylnaltrexone, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.
Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Relistor only for the indication prescribed.
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
Copyright 1996-2018 Cerner Multum, Inc. Version: 6.02.
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