Entereg Capsules

Entereg Capsules Patient Information Including Side Effects

Brand Names: Entereg

Generic Name: alvimopan (Pronunciation: AL vi MOE pan)

What is alvimopan (Entereg Capsules)?

Alvimopan reduces certain side effects of narcotic medications that are often used to prevent pain caused by surgery.

Narcotic medications can cause stomach pain, bloating, nausea, vomiting, and constipation. These side effects can delay recovery in patients undergoing gastrointestinal surgery.

Alvimopan works by preventing these side effects without reducing the pain-relieving effects of the narcotic.

Alvimopan is used to speed recovery of stomach and intestinal functions after a gastrointestinal surgery and to prevent side effects caused by narcotic medications.

Alvimopan may also be used for other purposes not listed in this medication guide.

What are the possible side effects of alvimopan (Entereg Capsules)?

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Tell your caregivers at once if you have a serious side effect such as:

  • pale skin, easy bruising or bleeding, weakness;
  • painful or difficult urination;
  • urinating less than usual or not at all; or
  • confusion, uneven heart rate, extreme thirst, increased urination, leg discomfort, muscle weakness or limp feeling.

Less serious side effects may include:

  • stomach pain or upset;
  • nausea, vomiting; diarrhea;
  • constipation, gas; or
  • back pain.

This is not a complete list of side effects and others may occur. Tell your doctor about any unusual or bothersome side effect. You may report side effects to FDA at 1-800-FDA-1088.

Read the Entereg Capsules (alvimopan capsules) Side Effects Center for a complete guide to possible side effects

What is the most important information I should know about alvimopan (Entereg Capsules)?

You should not use this medication if you are allergic to alvimopan, or if you have used a narcotic medication within the past 7 days. You may be more likely to have unpleasant effects on your stomach if you have recently taken a narcotic medication.

Before you receive alvimopan, tell your doctor if you have liver or kidney disease.

Alvimopan is given only in a hospital for a short period of time.

Tell your caregivers right away if you have pale skin, easy bruising or bleeding, painful or difficult urination, or confusion with uneven heart rate, leg discomfort, muscle weakness or limp feeling, and increased urination.

Side Effects Centers

Additional Entereg Capsules Information

Report Problems to the Food and Drug Administration


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

Women's Health

Find out what women really need.