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  • Generic Name: (methylnaltrexone bromide)
    Other Brands: N/A
  • Last Revised: 08/2016
    • What is this medication and its most common uses?

      Relistor is a medicine used to treat constipation in adults that is caused by prescription pain medicines called opioids. Relistor is available as tablets and a subcutaneous injection (injected just below the skin).

      Relistor tablets and Relistor injection are used to treat constipation caused by opioids in adults with chronic (long-lasting) pain that is not caused by cancer. Relistor injection is used to treat constipation caused by opioids in adults who are receiving treatment for advanced illness, when other medicines for constipation have not worked well enough.

    • What should I know when beginning and continuing on this medication?

      How does this medication work?

      Relistor works by protecting the stomach and intestines from the constipating effects of opioid medications.

      What are the beneficial effects of this medication and when should I begin to have results?

      What: In a clinical study, 59% of people receiving Relistor experienced at least 3 bowel movements per week (compared to 38% of people not receiving Relistor).

      When: In a clinical study, 33% of people receiving Relistor experienced a bowel movement within 4 hours of their first dose. However, everyone responds differently to treatment, so try to be patient and follow your healthcare provider's instructions.

      How do I know it is working?

      You may have bowel movements more often after you start using Relistor. This is a good indicator that your medication is working. Your healthcare provider may ask you questions and order tests to assess how well your condition is being treated.

    • What are the possible side effects of this medication?

      The following is not a full list of side effects. Side effects cannot be anticipated. If any develop or change in intensity, tell your healthcare provider as soon as possible. Only your healthcare provider can determine if it is safe for you to continue taking this medication.

      More common side effects of Relistor tablets in people with chronic pain that is not caused by cancer may include: abdominal (stomach area) pain, diarrhea, headache, swelling or a feeling of fullness or pressure in your abdomen, vomiting, sweating, anxiety, muscle spasms, runny nose, chills.

      More common side effects of Relistor injection in people with chronic pain that is not caused by cancer may include: abdominal pain, nausea, diarrhea, sweating, hot flush, shaking, chills.

      More common side effects of Relistor injection in people with advanced illness may include: abdominal pain, gas, nausea, dizziness, diarrhea.

      Less common side effects of Relistor may include:

      Tear in your stomach or intestinal wall, with symptoms such as stomach pain that is severe, does not go away, or gets worse.

      Diarrhea that is severe or that will not go away.

      Opioid withdrawal, with symptoms such as sweating, chills, diarrhea, stomach pain, anxiety, and yawning.

    • Who should not take this medication?

      Do not use Relistor if you are allergic to it or to any of its ingredients.

      Do not use Relistor if you have a blockage in your intestines or a history of intestinal blockage.

    • What should I tell my healthcare provider before I take the first dose of this medication?

      Tell your healthcare provider about all prescription, over-the-counter, and herbal medications you are taking before beginning treatment with Relistor. Also, talk to your healthcare provider about your complete medical history, especially if you have kidney or liver problems, have any stomach or intestinal problems (including stomach ulcer, Crohn's disease, diverticulitis, cancer of the stomach or intestines, or Ogilvie's syndrome), are pregnant, plan to become pregnant, or are breastfeeding.

    • What is the usual dosage?

      The information below is based on the dosage guidelines your healthcare provider uses. Depending on your condition and medical history, your healthcare provider may prescribe a different regimen. Do not change the dosage or stop taking your medication without your healthcare provider's approval.

      Opioid-Induced Constipation in Adults with Chronic Non-Cancer Pain

      Tablets: The recommended dose is 450 milligrams (mg) once a day in the morning.

      Injection: The recommended dose is 12 milligrams (mg) once a day.

      Opioid-Induced Constipation in Adults with Advanced Illness

      Injection: Inject one dose every other day, as needed. Your healthcare provider will prescribe the appropriate dose for you, based on your body weight. Do not inject more than one dose in a 24-hour period.

      If you have kidney or liver problems, your healthcare provider may adjust your dose appropriately.

    • How should I take this medication?

      Use Relistor exactly as prescribed by your healthcare provider. Do not change your dose without first talking to your healthcare provider.

      Stay close to a toilet after using Relistor.

      Stop using Relistor if you stop taking your prescription opioid pain medicine. Tell your healthcare provider if your pain medicine changes.

      If you are using Relistor for chronic pain that is not caused by cancer, stop taking other laxatives before you start treatment with Relistor. You may use other laxatives if Relistor does not work after 3 days of treatment.


      Take Relistor tablets with water on an empty stomach at least 30 minutes before your first meal of the day.

      Injection (Vials and Pre-Filled Syringes):

      Be sure to review the instructions that came with your prescription before you start using Relistor injection.

      Relistor is injected under the skin of the upper arm, abdomen, or thigh. Rotate your injection site each time you inject Relistor.

    • What should I avoid while taking this medication?

      Do not use the Relistor vials or pre-filled syringes if the liquid looks discolored or cloudy, or has any particles in it.

    • What are the possible food and drug interactions associated with this medication?

      If Relistor is used with certain other drugs, the effects of either could be increased, decreased, or altered. It is especially important to check with your healthcare provider before combining Relistor with similar medicines (such as naloxone or naltrexone).

    • May I receive this medication if I am pregnant or breastfeeding?

      Taking Relistor during pregnancy may cause opioid withdrawal symptoms in your unborn baby. The effects of Relistor during breastfeeding are unknown. Do not breastfeed while you are using Relistor. Tell your healthcare provider immediately if you are pregnant, plan to become pregnant, or are breastfeeding.

    • What should I do if I miss a dose of this medication?

      If you miss a dose of Relistor, use it as soon as you remember. However, if it is almost time for your next dose, skip the one you missed and return to your regular dosing schedule. Do not inject two doses at once.

    • How should I store this medication?


      Store at room temperature. The bottle contains 2 desiccant canisters to help keep your medicine dry. Do not remove the desiccant canisters from the bottle.

      Injection (Vials and Pre-Filled Syringes):

      Store at room temperature. Do not freeze. Keep away from light until you are ready to use the vials or pre-filled syringes.

      If the contents of a vial have been drawn into a syringe and you are not able to use the medicine right away, keep the syringe at room temperature for up to 24 hours.

    • Who should I contact in case of emergency or overdose?
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      In the event of a medical emergency call your doctor or 9-1-1 immediately. In the event of overdose, call your doctor or poison control for further instructions.
      National Poison Control#: Call 1-800-222-1222

      This PDR+ drug information has been developed by the Physicians’ Desk Reference Network (PDRN), a source of medication information trusted by doctors for over 65 years.

      This monograph summarizes the most important information about your medication and does not cover all the information you may need. If you have any questions or concerns or want to learn more about your medication, ask your healthcare provider; he/she will be able to provide answers to your questions. This medication should only be used by the patient for whom it was prescribed and should not be shared with other people.
    • Additional patient resources.
      back to top Use your PDR® Pharmacy Discount Card when you or a family member fills a prescription and ask for your PDR® Discount every
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