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Alvimopan Side Effects

In Summary

More frequently reported side effects include: constipation. See below for a comprehensive list of adverse effects.

For the Consumer

Applies to alvimopan: oral capsule

In addition to its needed effects, some unwanted effects may be caused by alvimopan. In the event that any of these side effects do occur, they may require medical attention.

Major Side Effects

You should check with your doctor immediately if any of these side effects occur when taking alvimopan:

More common:
  • Acid or sour stomach
  • belching
  • bloated
  • convulsions
  • decreased urine
  • difficulty having a bowel movement (stool)
  • dry mouth
  • excess air or gas in stomach or intestines
  • full feeling
  • heartburn
  • increased thirst
  • indigestion
  • irregular heartbeat
  • loss of appetite
  • mood changes
  • muscle pain or cramps
  • nausea or vomiting
  • numbness or tingling in hands, feet, or lips
  • pale skin
  • passing gas
  • shortness of breath
  • stomach discomfort, upset, or pain
  • troubled breathing with exertion
  • unusual bleeding or bruising
  • unusual tiredness or weakness
Less common:
  • Decrease in frequency of urination
  • decrease in urine volume
  • difficulty in passing urine (dribbling)
  • painful urination

Minor Side Effects

Some of the side effects that can occur with alvimopan may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

Less common:
  • Back pain

For Healthcare Professionals

Applies to alvimopan: oral capsule


Hematologic side effects including anemia (5.2% to 5.4%).[Ref]


Genitourinary side effects have included urinary retention (3.2% to 3.5%).[Ref]


Gastrointestinal side effects have included constipation (4% to 9.7%), flatulence (3.1% to 8.7%), and dyspepsia (5.9% to 7%).[Ref]


Metabolic side effects have included hypokalemia (6.9% to 9.5%).[Ref]


Musculoskeletal side effects have included back pain (3.3% to 3.4%).[Ref]


1. "Product Information. Entereg (alvimopan)." GlaxoSmithKline, Research Triangle Park, NC.

Not all side effects for alvimopan may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

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