Symptoms of Constipation from Opioid Use

Counting the number of times you have a bowel movement (BM) in a day or a week may not always be the most reliable way to tell if you are constipated. The signs and symptoms of constipation caused by opioids may include:

  • Hard or lumpy stools
  • Infrequent stools (fewer than 3 per week)
  • Excessive straining
  • Sense of incomplete emptying

All of these can lead to a frustrating time in the bathroom. Think back to when you started pain medicine. Did your bowel habits change? If they did, getting the right treatment for you is very important.


RELISTOR® is a prescription medicine used to treat constipation that is caused by prescription pain medicines called opioids, in adults:

  • with long-lasting (chronic) pain that is not caused by cancer.
  • receiving treatment for advanced illness, when other medicines for constipation have not worked well enough.
    • It is not known if RELISTOR is safe and effective if used for longer than 4 months in people with advanced illness.

Important Safety Information

Do not take RELISTOR® (methylnaltrexone bromide) Subcutaneous Injection if you have or may have a blockage in your intestines (called an intestinal obstruction) or a history of bowel blockage.

RELISTOR can cause serious side effects such as a tear in your stomach or intestinal wall (perforation). Stomach pain that is severe can be a sign of a serious medical condition. If you get stomach pain that does not go away, stop taking RELISTOR and get emergency medical help right away.

Stop using RELISTOR and call your healthcare provider if you get diarrhea that is severe or that does not go away during treatment with RELISTOR.

You may have symptoms of opioid withdrawal during treatment with RELISTOR including sweating, chills, diarrhea, stomach pain, anxiety, and yawning. Tell your healthcare provider if you have any of these symptoms.

Tell your healthcare provider if you have kidney problems or if you have any stomach or bowel (intestines) problems, including stomach ulcer, Crohn’s disease, diverticulitis, cancer of the stomach or bowel, or Ogilvie’s syndrome. Also, tell your healthcare provider about all of the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.

Tell your healthcare provider if you are pregnant or plan to become pregnant. Taking RELISTOR during pregnancy may cause opioid withdrawal symptoms in your unborn baby. Tell your healthcare provider right away if you become pregnant during treatment with RELISTOR. It is not known if RELISTOR passes into your breast milk. Taking RELISTOR while you are breastfeeding may cause opioid withdrawal in your baby. You and your healthcare provider should decide if you will take RELISTOR or breastfeed. You should not do both.

The most common side effects of RELISTOR in people with long-lasting (chronic) pain that is not caused by cancer include: stomach-area (abdomen) pain, nausea, diarrhea, sweating, hot flush, tremor, and chills.

The most common side effects of RELISTOR in people receiving treatment for their advanced illness include: stomach-area (abdomen) pain, gas, nausea, dizziness, and diarrhea.

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit or call 1-800-FDA-1088.

For product information, adverse event reports, and product complaint reports, please contact:

Salix Product Information Call Center
Phone: 1-800-508-0024
Fax: 1-510-595-8183

Click here for full Prescribing Information.

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