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Generic name: alvimopan systemic

Brand names: Entereg

Boxed Warning

Myocardial infarction:

There was a greater incidence of myocardial infarction (MI) in alvimopan-treated patients compared to placebo-treated patients in a 12-month clinical trial, although a causal relationship has not been established. In short-term trials with alvimopan, no increased risk of MI was observed.

Appropriate use:

Because of the potential risk of MI with long-term use, alvimopan is available only through a restricted program for short-term use (15 doses) under a Risk Evaluation and Mitigation Strategy (REMS) called the ENTEREG Access Support and Education (E.A.S.E.) Program.

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Capsule, Oral:

Entereg: 12 mg


Mechanism of Action

An opioid receptor antagonist which blocks opioid binding at the mu receptor; alvimopan has restricted ability to cross the blood-brain barrier at therapeutic doses. It selectively and competitively binds to the GI tract mu opioid receptors and antagonizes the peripheral effects of opioids on gastrointestinal motility and secretion. Does not affect opioid analgesic effects or induce opioid withdrawal symptoms.



Vd: 20 to 40 L


Hydrolyzed to an amide hydrolysis compound (active metabolite) by gut microflora; further metabolism of active metabolite to glucuronide conjugates and other minor metabolites


Urine (~35% as unchanged drug and metabolites); feces (via biliary excretion)

Time to Peak

Plasma: Parent drug: ~2 hours; Metabolite: 36 hours

Half-Life Elimination

10 to 17 hours

Protein Binding

Parent drug: 80%; metabolite: 94% (both primarily to albumin)

Use in Specific Populations

Special Populations: Renal Function Impairment

The half-life was comparable in patients with mild or moderate renal function impairment. There may be drug accumulation in patients with severe renal function impairment receiving multiple doses.

Special Populations: Hepatic Function Impairment

Drug exposure tended to be higher in patients with mild or moderate hepatic function impairment compared with healthy controls. There were no consistent effects on Cmax or half-life in patients with hepatic function impairment.

Use: Labeled Indications

Postoperative ileus: To accelerate the time to upper and lower GI recovery following surgeries including partial bowel resection with primary anastomosis


Use of opioids at therapeutic doses for more than 7 consecutive days immediately prior to alvimopan

Dosage and Administration

Dosing: Adult

Note: For short-term hospital use only.

Postoperative ileus: Oral: 12 mg 30 minutes to 5 hours prior to surgery, followed by 12 mg twice daily beginning the day after surgery until discharge for a maximum of 7 days (maximum total treatment: 15 doses [180 mg total])

Dosing: Geriatric

Refer to adult dosing.


Oral: For short-term hospital use only. Administer first dose 30 minutes to 5 hours prior to surgery. May be administered without regard to food.

Dietary Considerations

High-fat meals may decrease the rate and extent of absorption


Store at 25°C (77°F); excursions permitted to 15°C to 30°C (59°F to 86°F).

Alvimopan Images

Drug Interactions

Methylnaltrexone: May enhance the adverse/toxic effect of Opioid Antagonists. Specifically, the risk for opioid withdrawal may be increased. Avoid combination

Naldemedine: Opioid Antagonists may enhance the adverse/toxic effect of Naldemedine. Specifically, the risk for opioid withdrawal may be increased. Avoid combination

Naloxegol: Opioid Antagonists may enhance the adverse/toxic effect of Naloxegol. Specifically, the risk for opioid withdrawal may be increased. Avoid combination

Opioid Agonists: May enhance the adverse/toxic effect of Alvimopan. This is most notable for patients receiving long-term (i.e., more than 7 days) opiates prior to alvimopan initiation. Management: Alvimopan is contraindicated in patients receiving therapeutic doses of opioids for more than 7 consecutive days immediately prior to alvimopan initiation. Consider therapy modification

Adverse Reactions

Note: Incidence reported limited to bowel resection patients only.

1% to 10%:

Endocrine & metabolic: Hypokalemia (10%)

Gastrointestinal: Dyspepsia (2% to 7%)

Genitourinary: Urinary retention (3%)

Hematologic and oncologic: Anemia (5%)

Neuromuscular & skeletal: Back pain (3%)

Frequency not defined:

Cardiovascular: Myocardial infarction


Concerns related to adverse effects:

  • Cardiovascular effects: [US Boxed Warning]: A trend towards an increased incidence of MI was observed in alvimopan (low dose) treated patients compared to placebo in a 12-month study in patients treated with opioids for chronic pain. Other short-term studies have not observed this trend and a causal relationship has not been found. MI was generally observed more frequently in the initial 1 to 4 months of treatment.

Disease-related concerns:

  • Anastomosis: Use not recommended in patients having gastric or pancreatic anastomosis.
  • Complete bowel obstruction: Use not recommended in patients undergoing surgery for complete bowel obstruction.
  • Hepatic impairment: Use with caution in patients with mild to moderate hepatic impairment (Child-Pugh classes A and B); use not recommended with severe impairment (Child-Pugh class C).
  • Renal impairment: Use with caution in patients with renal impairment; use not recommended in patients with ESRD.

Concurrent drug therapy issues:

  • Opioids: Use with caution in patients recently exposed to opioids; may be more sensitive to gastrointestinal adverse effects (eg, abdominal pain, diarrhea, nausea and vomiting). Contraindicated in patients who have received therapeutic opioids for >7 consecutive days immediately prior to use.

Special populations:

  • Japanese patients: Patients of Japanese descent should be monitored closely for gastrointestinal side effects (eg, abdominal pain, cramping, diarrhea) due to possibility of greater drug exposure; discontinue use if side effects occur.

Other warnings/precautions:

  • Appropriate use: [US Boxed Warning]: For short-term (≤15 doses) hospital use only. Only hospitals that have registered through the ENTEREG Access Support and Education (E.A.S.E.™) Program and met all requirements may use. It will not be dispensed to patients who have been discharged from the hospital.

Monitoring Parameters

GI adverse reactions (eg, abdominal pain, cramping, diarrhea) in patients receiving more than 3 doses of an opioid within the week prior to surgery, patients with mild to moderate hepatic impairment, with severe renal impairment, or in patients who are Japanese.


Pregnancy Considerations

Adverse events have not been observed in animal reproduction studies.

Patient Education

What is this drug used for?

  • It is used to help bowel function after surgery.

Other side effects of this drug: Talk with your doctor right away if you have any of these signs of:

  • Chest pain
  • Fast heartbeat
  • Severe dizziness
  • Passing out
  • Severe headache
  • Severe nausea
  • Severe diarrhea
  • Vomiting
  • Abdominal pain
  • Abdominal cramps
  • Signs of a significant reaction like wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat.

Note: This is not a comprehensive list of all side effects. Talk to your doctor if you have questions.

Consumer Information Use and Disclaimer: This information should not be used to decide whether or not to take this medicine or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this medicine. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not specific medical advice and does not replace information you receive from the healthcare provider. You must talk with the healthcare provider for complete information about the risks and benefits of using this medicine.

Source: Wolters Kluwer Health. Last updated February 6, 2020.