(alvimopan) capsules 12 mg, for oral use


Improved time to GI recovery

For patients undergoing partial bowel resections with primary anastomosis, adding ENTEREG to a postoperative accelerated care pathway (ACP) improved mean time to gastrointestinal (GI) recoverya by up to 1.3 days.1

Phase 3 Bowel Resection Studies Graph: ENTEREG® (alvimopan) vs Placebo for GI Recovery in Hours
Phase 4 Radical Cystectomy Study Graph: ENTEREG® (alvimopan) vs Placebo for GI Recovery in Hours

(a) GI recovery was defined as the time to toleration of solid food and first bowel movement. Median time to GI recovery was improved with use of ENTEREG by 17 hours (Study 1, Study 2), 15 hours (Study 3), 12 hours (Study 4), and 3 hours (Study 5) in the phase 3 bowel resection studies and 29 hours in the phase 4 radical cystectomy study (Study 6).1 Patient numbers are for modified intent-to-treat (ITT); dose of ENTEREG used was 12 mg.

The ACP used in clinical trials included:

  • Early diet advancement
  • Early nasogastric tube (NGT) removal
  • Early ambulation

Study design

Data are from 5 multicenter, randomized, double-blind, parallel-group, placebo-controlled studies in patients undergoing bowel resection and 1 randomized, double-blind, placebo-controlled study in patients undergoing radical cystectomy (5 US studies and 1 non-US bowel resection study; ENTEREG: n=1096; placebo: n=1058; 54% male; 89% Caucasian).

Patients 18 years of age or older (average age: 62 years) who underwent open bowel resection surgeries that included primary anastomosis (partial large or small bowel resection surgery or radical cystectomy for bladder cancer) were administered ENTEREG 12 mg or placebo 30 minutes to 5 hours prior to surgery and twice daily after surgery until discharge, for a maximum of 7 days.

There were no limitations on the types of general anesthesia used.

The primary endpoint for all studies was time to achieve resolution of postoperative ileus, a clinically defined composite measure of both upper and lower GI recovery. GI2 (toleration of solid food and first bowel movement) is shown above, as it represents the most objective and clinically relevant measure of treatment response. The efficacy of ENTEREG following total abdominal hysterectomy has not been established.

Study exclusions

Patients who received more than 3 doses of an opioid (regardless of route) during the 7 days prior to surgery and patients with complete bowel obstruction or who were scheduled for a total colectomy, colostomy, or ileostomy were excluded. Intrathecal or epidural opioids or anesthetics were prohibited.


ENTEREG is indicated to accelerate the time to upper and lower gastrointestinal recovery following surgeries that include partial bowel resection with primary anastomosis.

Selected Safety Information


  • Increased incidence of myocardial infarction was seen in a clinical trial of patients taking alvimopan for long-term use. No increased risk was observed in short-term trials.
  • Because of the potential risk of myocardial infarction, ENTEREG is available only through a restricted program for short-term use (15 doses) called the ENTEREG Access Support and Education (E.A.S.E.) Program.


ENTEREG Capsules are contraindicated in patients who have taken therapeutic doses of opioids for more than 7 consecutive days immediately prior to taking ENTEREG.

Warnings and Precautions

There were more reports of myocardial infarctions in patients treated with alvimopan 0.5 mg twice daily compared with placebo-treated patients in a 12-month study of patients treated with opioids for chronic pain. In this study, the majority of myocardial infarctions occurred between 1 and 4 months after initiation of treatment. This imbalance has not been observed in other studies of alvimopan, including studies of patients undergoing bowel resection surgery who received alvimopan 12 mg twice daily for up to 7 days. A causal relationship with alvimopan has not been established.

E.A.S.E. Program for ENTEREG: ENTEREG is available only to hospitals that enroll in the E.A.S.E. ENTEREG REMS Program. To enroll in the E.A.S.E. Program, the hospital must acknowledge that:

  • Hospital staff who prescribe, dispense, or administer ENTEREG have been provided the educational materials on the need to limit use of ENTEREG to short-term, inpatient use
  • Patients will not receive more than 15 doses of ENTEREG
  • ENTEREG will not be dispensed to patients after they have been discharged from the hospital

ENTEREG should be administered with caution to patients receiving more than 3 doses of an opioid within the week prior to surgery. These patients may be more sensitive to ENTEREG and may experience GI side effects (eg, abdominal pain, nausea and vomiting, diarrhea).

ENTEREG is not recommended for use in patients with severe hepatic impairment, end-stage renal disease, complete gastrointestinal obstruction, or pancreatic or gastric anastomosis, or in patients who have had surgery for correction of complete bowel obstruction.

Adverse Reactions

The most common adverse reaction (incidence ≥1.5%) occurring with a higher frequency than placebo among ENTEREG-treated patients undergoing surgeries that included a bowel resection was dyspepsia (ENTEREG, 1.5%; placebo, 0.8%).

Before prescribing ENTEREG, please read the accompanying Prescribing Information, including the Boxed Warning about potential risk of myocardial infarction with long-term use.


1. Data available on request from Merck & Co., Inc., Professional Services-DAP, WP1-27, PO Box 4, West Point, PA 19486-0004. Please specify information package ANES-1149074-0001.