April 26, 2017

Entereg Capsules

(alvimopan) Capsules


ENTEREG is available only for short-term (15 doses) use in hospitalized patients. Only hospitals that have registered in and met all of the requirements for the ENTEREG Access Support and Education (E.A.S.E.) program may use ENTEREG. [see WARNINGS AND PRECAUTIONS]


ENTEREG Capsules contain alvimopan, a peripherally-acting µ-opioid receptor (PAM-OR) antagonist. Chemically, alvimopan is the single stereoisomer [[2(S)-[[4(R)-(3-hydroxyphenyl)-3(R),4-dimethyl-1-piperidinyl]methyl]-1-oxo-3-phenylpropyl]amino]acetic acid dihydrate. It has the following structural formula:

  (alvimopan) Structural Formula Illustration

Alvimopan is a white to light beige powder with a molecular weight of 460.6, and the empirical formula is C25H32N2O4•2H2O. It has a solubility of < 0.1 mg/mL in water or buffered solutions between pH 3.0 and 9.0, 1 to 5 mg/mL in buffered solutions at pH 1.2, and 10 to 25 mg/mL in aqueous 0.1 N sodium hydroxide. At physiological pH, alvimopan is zwitterionic, a property that contributes to its low solubility.

ENTEREG Capsules for oral administration contain 12 mg of alvimopan on an anhydrous basis suspended in the inactive ingredient polyethylene glycol.

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

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, feeling light-headed or short of breath, rapid heart rate, trouble concentrating;
  • painful or difficult urination;
  • urinating less than usual or not at all;
  • confusion, uneven heart rate, extreme thirst, increased urination, leg discomfort, muscle weakness or limp feeling; or
  • chest pain or heavy...

Read All Potential Side Effects and See Pictures of Entereg Capsules »

Last reviewed on RxList: 11/15/2016
This monograph has been modified to include the generic and brand name in many instances.

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.

Use Pill Finder Find it Now See Interactions

Pill Identifier on RxList

  • quick, easy,
    pill identification

Find a Local Pharmacy

  • including 24 hour, pharmacies

Interaction Checker

  • Check potential drug interactions
Search the Medical Dictionary for Health Definitions & Medical Abbreviations