Pharmacology Update
Alvimopan Capsules (Entereg®)
By William T. Elliott, MD, FACP, and James Chan, PharmD, PhD. Dr. Elliott is Chair, Formulary Committee, Northern California Kaiser Permanente; Assistant Clinical Professor of Medicine, University of California, San Francisco; Dr. Chan is Pharmacy Quality and Outcomes Manager, Kaiser Permanente, Oakland, CA. Drs. Chan and Elliott report no financial relationship to this field of study.
The FDA has approved a drug to help patients regain bowel function following bowel resection surgery. Alvimopan is a peripherally acting mu-opioid receptor antagonist (PAM-OR). The product is a result of collaboration between GlaxoSmithKline and Adolor Corporation. It is marketed by GlaxoSmithKline as Entereg.
Indications
Alvimopan is indicated to accelerate the time to upper and lower gastrointestinal recovery following partial large or small bowel resection surgery with primary anastomosis. It is not recommended for patients undergoing surgery to correct bowel obstruction.1
Dosage
The recommended dose is 12 mg (one capsule) given 30 minutes to 5 hour prior to surgery followed by 12 mg twice daily for up to 7 days for a maximum of 15 capsules.
Alvimopan is available as 12 mg capsule.
Potential Advantages
Alvimopan is shown to be effective in treating post-operative ileus (POI) and accelerating postoperative GI recovery after abdominal surgery.1-5
Potential Disadvantages
Patients recently exposed to an opioid are expected to be more sensitive to the opioid antagonistic effects of alvimopan. Patients may experience abdominal pain, nausea, and diarrhea. Patients who have received more than 7 consecutive days of opioid therapy should not receive alvimopan. In a 12-month study with low dose (0.5 mg twice daily) alvimopan, a higher number of myocardial infarctions were reported relative to placebo. These were reported 1 to 4 months after initiation of treatment.1
Comments
Alvimopan is a PAM-OR antagonist that is intended to counter the effect of opioids on GI function and motility but does not block the analgesic effects of opioids. The efficacy and safety have been evaluated in 5 multicenter, randomized, placebo-controlled studies. Subjects were 18 years of age or older undergoing partial large or small bowel resection surgery with primary anastomosis.1 They were randomized to alvimopan 12 mg or placebo for a maximum of 7 days or until hospital discharge. All patients received opioid analgesia. The primary endpoint was time to resolution of postoperative ileus as defined by tolerance of solid food and first bowel movement. The recovery time was reduced by 11 to 26 hours, representing a 10 to 20% reduction in recovery time. A pooled analysis of a subset of patients following bowel resection reported that alvimopan reduced prolonged POI (1.4% vs 5%), prolonged stay or readmission combined (14% vs 24.4%), and need for NGT insertion (6.8% vs 12.2%).5 The drug may be more effective in patients who received intravenous patient-controlled analgesia (PCA) than non-PCA (eg, intravenous bolus analgesia).6 Alvimopan is not indicated for total abdominal hysterectomy a phase III study suggests reduction in time to first bowel movement but not earlier discharge or time to tolerance of first solid food.2 POI is generally less likely with total abdominal hysterectomies compared to bowel resection and these patients are generally discharged earlier.7 Alvimopan appears to be well tolerated with the most commonly reported adverse effects being anemia, dyspepsia, hypokalemia, back pain and urinary retention. The incidence of adverse effects did not differ significantly from placebo.1,4 Alvimopan is only available in hospitals that have registered in and met the requirements for the ENTEREG Access Support and Education program.
Clinical Implications
Patients undergoing major abdominal surgery are at high risk for developing postoperative ileus as characterized by impairment of bowel function. The cause appears to be multifactorial such as physical manipulation of the bowel, surgical trauma, inhaled anesthesia and opioids for postoperative analgesia.8 Mu-opioid receptor antagonists such as alvimopan may reduce the rate of POI by antagonizing the peripheral effects of opioid on the GI tract. Alvimopan is the first drug approved for this use. Methylnaltrexone, another antagonist, may also be effective.9 Currently there are no comparative studies.
References
1. Entereg Product Information. GlaxoSmithKline. May 2008.
2. Herzog TJ, et al. Am J Obstet Gynecol. 2006;195(2):445-453.
3. Wolff BG, et al. Ann Surg. 2004;240:728-735.
4. Tan EK, et al. Aliment Pharmacol Ther. 2006;25:47-57.
5. Delaney CP, et al. Ann Surg. 2007;245:355-363.
6. Buchler MW, et al. Aliment Pharmacol Ther. 2008;Mar 28 Epub.
7. Wolff GB, et al. J Am Coll Surg. 2007;205:43-51.
8. Luckey AQ, et al. Arch Surg. 2003;138:206-214.
9. McNicol E, et al. Cochrane Database Syst Rev 2008; Apr 16;(2):CD006332.
The FDA has approved a drug to help patients regain bowel function following bowel resection surgery.You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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