Managed Care - July 2008 - (Page 51) TOMORROW’S MEDICINE Alvimopan Hastens Recovery From Abdominal Surgery Commercial and public payers concerned by prolonged hospital stays will be considering this Thomas Morrow, MD P assing gas has been, except for teenagers and the more obtuse movies, a social faux pas. However, for patients who have recently had abdominal surgery, passing gas is actually a landmark event, a sign that their bowel functions are resuming, a welcome event for both the patient and the health care provider. It is also a welcome event for payers because patients recovering from abdominal surgery cannot be discharged without demonstrating bowel function. Bowel resection causes some of the worst post-operative ileus (POI). The trauma to the bowel, inhibitory sympathetic input, release of stress hormones and neurotransmitters, and the inescapable need for opioid analgesics combine to cause a long stay and hence, higher overall cost. POI can affect all segments of the gastrointestinal tract and may last more than five days. It is associated with bloating, abdominal distension, persistent abdominal pain, nausea, vomiting, an inability to eat or drink, and the accumulation of gas and fluids in the bowel, as well as delayed passage of flatus and defecation. POI has long been treated with rapid ambulation, optimizing opioid use, decreasing nasogastric suction, and early challenge with clear liquids to “prime” the gut. Medication therapy has been all but ineffective. That has all changed with the recent, though twice delayed, approval of a new drug, alvimopan with the brand name of Entereg. It is the first drug with the FDA approved indication “to accelerate upper and lower gastrointestinal recovery following partial large or small bowel resection surgery with primary anastomosis.” Alvimopan is a selective, peripherally acting µ-opioid receptor antagonist. It works by competitively binding to µ-opioid receptors in the gut, selectively inhibiting the negative effects of opioid medications on gastrointestinal (GI) function and motility without affecting the central nervous system analgesic effects. It is given as a 12 mg capsule dose administered 30 minutes to five hours before surgery, followed by 12 mg twice a day for a maximum of seven days. Plasma concentration peaks approximately two hours post ingestion. No significant accumulation occurs when dosed twice per day. A metabolite with µ-opioid receptor antagonistic properties also is present in the systemic circulation shortly after ingestion. This metabolite is the result of intestinal flora metabolism, not liver metabolism. It has no derogatory properties. Alvimopan is cleared by biliary secretion in the feces and urine. The mean half-lives of alvimopan and its metabolite are approximately the same: 10–18 hours. Clinical trials Alvimopan was evaluated in five multicenter, randomized, double-blind, parallel-group, placebo-controlled studies, four of which were performed in the United States. Studies involved patients age 18 or older undergoing either of two types of abdominal surgery under general anesthesia — partial large or small bowel resection surgery with primary anastomosis, or total abdominal hysterectomy. All U.S. patients were scheduled to receive intravenous patient-controlled opioid analgesia. Non-U.S. patients were scheduled to receive intravenous patient-controlled bolus parenteral opioid analgesia. The opioid used was left to the discretion of the treating physician. A standard accelerated postoperative care pathway was implemented: early nasogastric tube removal, early Thomas Morrow, MD, is the immediate past president of the National Association of Managed Care Physicians. He has 23 years of managed care experience at the payer or health plan level. JULY 2008 / MANAGED CARE 51
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