Alvimopan, a novel, peripherally acting mu opioid antagonist: results of a multicenter, randomized, double-blind, placebo-controlled, phase III trial of major abdominal surgery and postoperative ileus

Prospective randomized, double-blind, placebo-controlled study of pre- and postoperative administration of a COX-2-specific inhibitor as opioid-sparing analgesia in major colorectal surgery

PURPOSE

To demonstrate the opioid-sparing effect and reduction in postoperative ileus obtained with valdecoxib 40 mg administered pre- and postoperatively in patients undergoing colorectal resection.

METHODS

Patients for elective colorectal resection from December 2002 to June 2004 were randomized to receive either valdecoxib or placebo with standard patient-controlled analgesia (PCA) morphine. In the study arm, the first dose of valdecoxib 40 mg was administered orally as close as possible to 1 h prior to the start of surgery. Each subsequent dose was administered at 24-h intervals up to 120 h. Patients in the control arm were served placebos at the same time-points.

RESULTS

Forty patients were enrolled in the study arm and 39 (excluding one protocol violation) in the control arm. The groups were comparable in age, sex, American Society of Anesthesiology status, body mass index, incision length, and duration and types of operations. Mean PCA doses at 12 and 24 h were 18.6 and 28.3 mg in the study arm vs 26.2 and 41.2 mg in controls, representing a one-third opioid reduction. Bowel sound and movement first appeared at medians of 12 and 72 h in the study arm vs 24 and 84 h, respectively, in controls (P < 0.05). Tolerance of solid diet was at a median of 60 h and discharge at a median of 4 days in the study arm vs 72 h and 6 days in controls (P < 0.05 and P < 0.01, respectively). Seven (18%) morbidities occurred in the control vs six (15%) in the study arm.

CONCLUSIONS

Patients treated with a cyclo-oxygenase 2-specific inhibitor have a shorter recovery time when compared with patients on a standard postoperative PCA morphine-only regimen after colorectal resection.

Management of complications in surgery of the colon

BACKGROUND

General surgeons are frequently confronted with colorectal diseases in their daily practice, whereby colorectal cancer is the second most common malignant tumour, with almost 5000 new cases every year in Austria. The incidence of benign colon disorders requiring surgery (e.g. colon polyps, sigmoid diverticulitis) is also increasing. The first aim in colon surgery should be to avoid complications and if they occur to treat them properly.

METHODS

We basically distinguish between general and special complications. As general complications, prevention of malnutrition and support of the immune system should receive special attention. As the number of elderly patients increases, so does the risk not only of thrombembolic complications but also of critical cardiocirculatory situations, and renal and hepatic failure. Special complications depend either on the type of surgery (laparoscopic assisted, conventional open surgery) or the techniques employed (stapled, hand sutured). Handling of the tissue also plays a major role (e.g. dry versus wet pads).

RESULTS

Shortening of the postoperative stay decreases both hospital costs and the incidence of infections, meaning that minimally invasive surgery and postoperative "fast track nutrition" should be promoted. Emergency operations should be avoided (e.g. bridging through colonic stents), as morbidity and mortality are clearly increased in comparison to (semi-) elective operations. During the operation itself, new equipment and techniques (such as Ultracision®, Ligasure®) as well as a well coordinated team help to reduce complications and duration of surgery.

CONCLUSIONS

To avoid is better than to repair. If complications do occur, appropriate surgical and intensive - care measures should be taken immediately.

Review of the pathophysiology and management of postoperative ileus

Investigations in the pathophysiology and treatment of postoperative ileus continue to evolve. Bowel rest is no longer a mandatory component of postoperative recovery. Tolerance of enteral nutrition and normalization of the abdominal examination are more accurate indications of the resolution of postoperative ileus than passage of flatus or first bowel movement. A multimodal "fast track" recovery approach incorporated into a clinical pathway provides a more rapid return of intestinal function and shortened hospital stay in patients undergoing major, uncomplicated gastrointestinal surgery.

Irritable bowel syndrome: recent and novel therapeutic approaches

Irritable bowel syndrome (IBS) is a highly prevalent functional gastrointestinal disorder affecting up to 3-15% of the general population in Western countries. It is characterised by unexplained abdominal pain, discomfort and bloating in association with altered bowel habits. The pathophysiology of IBS is considered to be multifactorial, involving disturbances of the brain-gut-axis: IBS has been associated with abnormal gastrointestinal motor functions, visceral hypersensitivity, psychosocial factors, autonomic dysfunction and mucosal inflammation. Traditional IBS therapy is mainly symptom oriented and often unsatisfactory. Hence, there is a need for new treatment strategies. Increasing knowledge of brain-gut physiology, mechanisms, and neurotransmitters and receptors involved in gastrointestinal motor and sensory function have led to the development of several new therapeutic approaches. This article provides a systematic overview of recently approved or novel medications that show promise for the treatment of IBS; classification is based on the physiological systems targeted by the medication. The article includes agents acting on the serotonin receptor or serotonin transporter system, novel selective anticholinergics, alpha-adrenergic agonists, opioid agents, cholecystokinin antagonists, neurokinin antagonists, somatostatin receptor agonists, neurotrophin-3, corticotropin releasing factor antagonists, chloride channel activators, guanylate cyclase-c agonists, melatonin and atypical benzodiazepines. Finally, the role of probiotics and antibacterials in the treatment of IBS is summarised.

Symptom control in palliative care--Part I: oncology as a paradigmatic example

Achieving the best quality of life for patients and their families when a disease becomes progressive and no longer remains responsive to curative therapy is the primary goal of palliative care. A comprehensive care plan focusing on control of physical symptoms as well as psychological, social, and spiritual issues then becomes paramount in that context. Symptom assessment and treatment are a principle part of palliative care. This paper is the first of three in a series addressing non-pain symptoms, which are frequently encountered in the palliative care populations. The most frequent non-pain symptoms are constipation, chronic nausea and vomiting, anorexia, dyspnea, fatigue, and delirium. As symptoms are subjective, their expression varies from patient to patient, depending on the individual patient's perception and on other factors such as psychosocial issues. While symptoms are addressed individually, patients frequently have multiple coexisting symptoms. Generally told, once the intensity of a symptom has been assessed, it is necessary to assess the symptom in the context of other symptoms such as pain, appetite, fatigue, depression, and anxiety. Given that fact, adopting a multidimensional assessment allows for formulation of a more effective therapeutic strategy. More pertinently, this paper highlights the management of non-pain symptoms as an integral part of patient care and reviews the pathophysiologies, causes, assessment, and management of constipation, chronic nausea, and vomiting, each of which is common among the palliative care population.

A double-blind, randomized, placebo-controlled phase III study of the safety of alvimopan in patients who undergo simple total abdominal hysterectomy

OBJECTIVE

The purpose of this study was to investigate the safety and efficacy of alvimopan, a novel peripherally acting mu-opioid receptor antagonist, in patients who undergo simple total abdominal hysterectomy.

STUDY DESIGN

Women (n = 519) were randomized (4:1) to receive alvimopan 12 mg (n = 413) or placebo (n = 106) > or = 2 hours before the operation then twice daily for 7 days (hospital and home). Adverse events were monitored up to 30 days after the last dose of study drug was administered. Efficacy was assessed for 7 postoperative days.

RESULTS

Overall, the most common adverse events were nausea, vomiting, and constipation; < 5% of patients discontinued use because of adverse events. Alvimopan significantly accelerated the time to first bowel movement (hazard ratio, 2.33; P <.001). Average time to first bowel movement was reduced by 22 hours, with more frequent bowel movement and better bowel movement quality found in the treatment cohort.

CONCLUSION

Alvimopan has a safety profile that is similar to that of placebo and provides significantly improved lower gastrointestinal recovery in women who undergo simple total abdominal hysterectomy.

The selective mu opioid receptor antagonist, alvimopan, improves delayed GI transit of postoperative ileus in rats

Postoperative ileus (POI) is often exacerbated by opioid analgesic use during and following surgery, since mu opioid receptor activation results in a further delay of gastrointestinal (GI) transit. The effects of alvimopan, a novel, selective, and peripherally acting mu opioid receptor antagonist, and the reference compound methylnaltrexone, upon POI were investigated in rats. Under isoflurane anesthesia, POI was induced by laparotomy with intestinal manipulation. Immediately after the surgery, the rats received (51)Cr by gavage. Three hours after the surgery, the rats were sacrificed and GI transit was estimated using the geometric center (GC) of (51)Cr. Alvimopan (0.1-3 mg/kg) or methylnaltrexone (100 mg/kg) were administered by gavage either before or after the surgery, with or without morphine administration (1 mg/kg). GI transit was delayed by intestinal manipulation (GC = 2.92 +/- 0.17). Alvimopan (1 and 3 mg/kg) significantly reversed this delayed GI transit when administered 45 min prior to surgery. However, the effects of alvimopan were less pronounced when administered following surgery. Morphine administration further delayed GI transit induced by intestinal manipulation (GC = 1.97 +/- 0.11). Under these conditions, alvimopan (1 and 3 mg/kg) also significantly improved delayed GI transit when administered before surgery. Methylnaltrexone was inactive under all experimental conditions. These data suggest that mu opioid receptors play a role in the pathogenesis of POI, and that the clinical benefit reported to be afforded by alvimopan may be in part mediated via inhibition of an endogenous opioid release as well as blockade of the unwanted GI actions of analgesic agents.

Pharmacokinetics of the opioid antagonist N-methylnaltrexone and evaluation of its effects on gastrointestinal tract function in horses treated or not treated with morphine

OBJECTIVE

To determine the pharmacokinetics and effects of the morphine antagonist N-methylnaltrexone (MNTX) on gastrointestinal tract function in horses when administered alone and in combination with morphine.

ANIMALS

5 healthy adult horses.

PROCEDURES

Horses were treated with MNTX (1 mg/kg, IV), and serial blood samples were collected for determination of drug pharmacokinetics. For evaluation of effects on the gastrointestinal tract when administered alone, MNTX was administered at a dosage of 0.75 mg/kg, IV, twice daily for 4 days. For evaluation of effects when administered concurrently with morphine, MNTX (0.75 mg/kg, IV, q 12 hours) and morphine (0.5 mg/kg, IV, q 12 hours) were administered for 6 days. Gastrointestinal variables evaluated were defecation frequency, weight of feces produced, fecal moisture content, intestinal transit time, and borborygmus scores.

RESULTS

The time-concentration data for MNTX disposition best fit a 2-compartment model with a steady-state volume of distribution of 244.6 +/- 21.8 mL/kg, t1/2 of 47.04 +/- 11.65 minutes, and clearance of 11.43 +/- 1.06 mL/min/kg. Adverse effects were not observed at doses <or= 1 mg/kg. Administration of MNTX increased daily fecal weight. When administered concurrently with morphine, MNTX partially prevented the effects of morphine on the gastrointestinal tract by increasing defecation frequency, fecal weight, fecal moisture content, and borborygmus score, and by preventing increases in intestinal transit time.

CONCLUSIONS AND CLINICAL RELEVANCE

Because MNTX does not cross the blood-brain barrier, administration of the drug should not alter the analgesic effects of opioids and may attenuate the adverse gastrointestinal effects associated with use of opioids in horses.

Peripherally Acting Mu-Opioid-Receptor Antagonists and the Connection Between Postoperative Ileus and Pain Management: The Anesthesiologist’s View and Beyond

The adverse effects of opioids are well documented. Because opioid receptors have a wide-ranging anatomic distribution, the effects subsequent to opioid binding, both good and bad, occur centrally and in the periphery. Postoperative strategies to reduce opioid burden, therefore, are in the patient's best interest. Multimodal analgesia is the key towards balancing the need for opioids while simultaneously reducing their burden. Alternative anesthesia and analgesia options such as regional anesthesia, nonsteroidal anti-inflammatory drugs, or cyclooxygenase-2 enzyme inhibitors should be considered part of multimodal protocols. Familiarity of where these drugs are active in the body and how they can be employed is imperative for all surgical team members. Optimal implementation of multimodal approaches can reduce hospital stay and improve clinical outcomes, including patient satisfaction. Finally, strategies that may help reduce rates of hospital readmission also contribute to overall improved outcome. New peripherally acting mu-opioid-receptor antagonists represent significant progress in the ability of perianesthesia nurses to play an even greater role in achieving these goals. In contrast to older opioid-receptor antagonists, these agents specifically target an important aspect of the multifactorial etiology of postoperative ileus (POI), mu-opioid-receptor-mediated activity in the GI tract. In addition, they do not pass the blood-brain barrier or diminish opioid-mediated analgesia. Advanced clinical trials have already demonstrated the ability of one of these agents, alvimopan, to reduce POI and improve other postoperative outcomes while maintaining adequate analgesia. Combined with other options aimed at reducing opioid burden, alvimopan and similar drugs in development hold promise as part of multimodal protocols to optimize pain management while minimizing postoperative morbidities.

Nurses Are Everywhere: A Practical Perspective on the Surgical Team in Managing Postoperative Ileus

Because the availability of new, peripherally acting mu-opioid-receptor antagonists is expected soon, it is important for all members of the surgical team to familiarize themselves with new approaches and also re-evaluate older approaches to help improve patient outcomes. "Preop nurses" have numerous responsibilities, among which are mitigating some of the adverse outcomes of surgery such as postoperative ileus (POI), making these nursing personnel indispensable to the proper implementation of multimodal management protocols for POI. Establishing basic preoperative procedures is an important primary consideration. Preoperative evaluation of general health, medical history (including surgical history), and an assessment of gastrointestinal (GI) function and habits should all be part of careful up-front assessment for each patient, especially because POI and other GI adverse effects are so often encountered in the PACU. Hand-in-hand with how we as nurses interact with our surgical colleagues is patient education regarding hospitalization and postrecovery expectations. PACU nurses will be key players in maintaining proper implementation of multimodal regimens, essentially doing this in two "phases": Phase I interventions comprise the ongoing assessment and monitoring of patients, administering medications, and evaluating patient satisfaction and overall status; Phase II considerations encompass a further set of practice guidelines that center on optimizing discharge status, including pain management and education as well as other discharge needs. Where new agents may fit into multimodal regimens that optimally incorporate preoperative and postanesthesia protocols remains to be determined. What is clear is that as nurses and the entire surgical team strive to enhance patient satisfaction, nursing personnel must assume leadership roles in how new multimodal strategies are implemented and executed. Advanced clinical data for the new peripherally acting mu-opioid-receptor antagonist alvimopan, and for the drug class as a whole, have contributed to a greater impetus on reassessing perioperative protocols and policy, helping to broach innovative clinical frontiers of how we treat pain and POI, and thus improve patient outcomes.

Current Choices—Good or Bad—for the Proactive Management of Postoperative Ileus: A Surgeon’s View

Postoperative ileus (POI) is frequently experienced by many patients undergoing abdominal operations and other surgical procedures. Postoperative ileus causes physical discomfort and may increase risk for prolonged hospital length of stay. Despite its prevalence, there is currently no accepted standard definition of POI and, consequently, no standardized mode of prevention or treatment; it is no wonder that a variety of management approaches for POI have been developed. Some of these include alternative surgical techniques such as laparoscopic or endoscopic procedures to minimize trauma and help lessen the release of endogenous mediators of POI. Others have evaluated alternate analgesic regimens such as thoracic epidural anesthetics to avoid stimulating opioid receptors in the gut. These approaches have had varying results. Other pharmacologic attempts to reduce POI have focused on the blockade of opioid receptors to prevent opioid-induced GI-related adverse effects. A new class of agents, peripherally acting mu-opioid-receptor antagonists such as methylnaltrexone and alvimopan, may improve the pharmacologic management of POI and reshape the current paradigm of multimodal management of POI. Protocols that incorporate these agents may offer yet another avenue to mitigate the adverse effects of POI, and thus help improve surgical outcomes. To date, alvimopan has been shown in phase 3 clinical trials to significantly reduce the duration of POI while maintaining satisfactory analgesia and reducing length of hospital stay. Combinations of strategies with demonstrated effectiveness such as early feeding, epidural analgesia, laparoscopic surgery, and peripherally acting mu-opioid-receptor antagonists may help transform the management of POI into an effective multimodal paradigm that targets the diverse etiologic factors leading to this common clinical problem. Clearly, all surgical team members are crucial in the optimal implementation of such multimodal approaches.

The Surgical Team and Outcomes Management: Focus on Postoperative Ileus

Postoperative ileus (POI) is defined as the impairment of bowel motility that occurs almost universally after major open abdominal procedures, as well as other abdominal and nonabdominal procedures. For the majority of affected patients, POI generally lasts approximately three to five days, but longer duration is not uncommon. The causes of POI are multifactorial, but can be broadly categorized into two groups: those related to the surgical procedure and those related to pharmacologic interventions (opioids). The fact that POI is generally transient and therefore self-limited should not deter the surgical team from seeking improved ways to mitigate its associated adverse effects, which can be substantial and immensely uncomfortable for the patient, and can have far-reaching implications regarding overall hospitalization costs for many types of surgeries. Optimization of POI management and prevention efforts is a responsibility of all members of the surgical team and can drastically affect the overall clinical outcome of major abdominal surgery. Depending on the individual team member's role, different perspectives and strategies may be used to achieve improved outcomes, including but not limited to hospitalization costs related to care and length of stay, resource utilization, and, perhaps most critically, patient quality of life not only immediately after surgery but also after discharge. The ability to reliably and significantly decrease the duration of POI should be readily recognized as an important objective in the management of this condition. Opioids will continue to be a mainstay of postoperative care regimens, but new agents such as peripherally acting mu-opioid-receptor antagonists may offer a unique clinical advantage by helping to reduce the adverse gastrointestinal effects of opioids while preserving their desired benefits for postoperative analgesia.

Postoperative upper and lower gastrointestinal recovery and gastrointestinal morbidity in patients undergoing bowel resection: pooled analysis of placebo data from 3 randomized controlled trials

BACKGROUND

This analysis examines gastrointestinal recovery in patients who underwent bowel resection (BR) in 3 recent trials.

METHODS

Patients who underwent BR in the placebo groups of 3 randomized, double-blind, phase III, parallel-group, multicenter alvimopan efficacy trials were analyzed.

RESULTS

Most patients tolerated solid food and had a bowel movement by postoperative day 4. The majority of patients were discharged from the hospital by day 6, but 24.4% required a prolonged hospital stay or readmission. The incidence of nausea was highest on the day of surgery and decreased thereafter, whereas vomiting was uncommon on the day of surgery but increased slightly on postoperative days 1 to 6. The incidence of postoperative nasogastric tube insertion was highest (12%) on day 2.

CONCLUSIONS

This analysis provides valuable clinical insight into gastrointestinal recovery after BR in a large homogenous patient population receiving multimodal care.

[(3)H]Alvimopan binding to the micro opioid receptor: comparative binding kinetics of opioid antagonists

Alvimopan is a novel peripheral micro opioid antagonist in clinical development for the management of post-operative ileus and opioid-induced bowel dysfunction. We hypothesized that the long duration of action of alvimopan might be related to a slower dissociation rate from the micro opioid receptor compared to other shorter acting antagonists. The dissociation rate of alvimopan from the micro opioid receptor (t(1/2)=30--44 min) was comparable to that of the long acting partial agonist buprenorphine (t(1/2)=44 min), but was slower than those of the antagonists naloxone (t(1/2)=0.82 min) and N-methylnaltrexone (t(1/2)=0.46 min). Also, increases in the apparent affinities and potencies of buprenorphine and alvimopan, but not of naloxone and methylnaltrexone, were observed upon preincubation with the micro opioid receptor. Consistent with its long duration of action, alvimopan has a slow dissociation rate from the micro opioid receptor compared to other shorter acting antagonists and may be more potent if administered prior to dosing with exogenous opioids.

Promotility medications--now and in the future

Gastrointestinal promotility drugs stimulate smooth muscle contractions to enhance gastric emptying and small and large bowel transit. Currently available drug classes with prokinetic properties include antidopaminergic agents, serotonergic agents, and motilin-receptor agonists. Due to moderate prokinetic effects, poor symptomatic responses and the presence of adverse effects, there is a clear need for new classes of prokinetics. Several newer prokinetic drugs and drug classes are currently under evaluation. Selecting candidate agents and designing the appropriate therapeutic trials is hampered by the lack of insight in the pathophysiology of motility-related symptoms. As gastrointestinal motor disorders are chronic, relapsing, and remitting disorders, it seems desirable that studies with candidate prokinetic drugs establish a long-term efficacy and not only short-term effects on gastrointestinal functions.

Peripheral opioids for functional GI disease: a reappraisal

Opioids have been used medicinally and recreationally for thousands of years. The clinical use of opioids for gastrointestinal conditions has been limited by central nervous system side effects. A new generation of peripheral opioid receptor ligands free of central nervous system side effects is being developed. Clinical trials with the peripherally acting mu opioid receptor antagonists' alvimopan and N-methylnaltrexone show promise for improving postoperative ileus- and opioid-induced constipation. Likewise, preliminary studies with the peripherally acting kappa opioid agonist fedotozine showed promise in the treatment of irritable bowel syndrome (IBS) and functional dyspepsia. Further studies are on hold presumably due to lack of efficacy in subsequent studies. However, clinical studies are underway for newer kappa opioid agonists such as asimadoline and ADL 10-0101.

Alvimopan, a peripherally acting mu-opioid receptor antagonist, compared with placebo in postoperative ileus after major abdominal surgery

BACKGROUND

Alvimopan is a peripherally acting mu-opioid receptor (PAM-OR) antagonist for accelerating gastrointestinal recovery after surgery.

METHODS

Patients undergoing open laparotomy (bowel resection, n = 418; hysterectomy, n = 197) were randomized to receive alvimopan 6 or 12 mg or placebo orally > or = 2 h before surgery and then b.i.d. until hospital discharge (up to 7 days). The primary efficacy endpoint was time to gastrointestinal (GI) recovery (measured by toleration of solid food and passage of flatus/stool; GI-3). Secondary endpoints included time to GI-2 recovery (toleration of solid food and passage of stool) and hospital discharge order written (DCO).

RESULTS

Alvimopan did not significantly accelerate GI-3 compared with placebo [6 mg: hazard ratio (HR) = 1.20, p = 0.080; 12 mg: HR = 1.24, p = 0.038). However, after adjustment for significant covariates (sex/surgical duration), benefits were significant for both doses (6 mg: HR = 1.24, p = 0.037; 12 mg: HR = 1.26, p = 0.028). Alvimopan also significantly accelerated time to GI-2 (6 mg: HR = 1.37, p = 0.008; 12 mg: HR = 1.33, p = 0.018) and DCO (6 mg: HR = 1.31, p = 0.008; 12 mg: HR = 1.28, p = 0.015). Adverse events were similar between groups.

CONCLUSIONS

Alvimopan (6 or 12 mg) accelerates GI recovery and is well tolerated in patients undergoing open laparotomy.

Basic and clinical pharmacology of new motility promoting agents

Recent research has provided new information about drugs that could be used to treat functional motility disorders. Promotility drugs accelerate gastric emptying or colonic transit and these properties may contribute to their efficacy in treating symptoms associated with gastroparesis, functional dyspepsia or constipation. 5-Hydroxytryptamine4 receptors are targets for drugs (tegaserod, renzapride) that treat symptoms in constipated irritable bowel syndrome patients and in gastroparesis. Drugs acting at motilin (erythromycin) and cholecystokinin-1 (dexloxiglumide) receptors accelerate gastric emptying. Dexloxiglumide might be useful in the treatment of functional dyspepsia particularly that associated with lipid intake. Alvimopan is a mu-opioid receptor antagonist that does not cross the blood brain barrier. Alvimopan is effective in treating postsurgical ileus and perhaps opiate-induced bowel dysfunction. Successes and failures of recent efforts to develop promotility agents revealed opportunities and challenges for developing new promotility drugs. The pharmacological properties of partial agonists might be exploited to develop effective promotility drugs. However, opposing actions of promotility agents on motility (increased contraction vs decreased accommodation) limit the clinical efficacy of drugs with these opposing actions. Selection of appropriate patient populations for evaluation of new drugs is also critical.

Alvimopan for the Management of Postoperative Ileus

OBJECTIVE:

To review the pharmacology, pharmacokinetics, clinical efficacy, safety, dosage, and administration of alvimopan, a peripherally acting μ-opioid receptor antagonist, in the management of postoperative ileus (POI).

DATA SOURCES:

A literature search (1980–October 2004%) applying the terms alvimopan, ADL 8–2698, and LY246736 was conducted using MEDLINE. Information was also obtained from scientific congress abstracts and data on file with the manufacturer.

STUDY SELECTION AND DATA EXTRACTION:

Studies and abstracts investigating alvimopan and POI were considered for inclusion; however, they were restricted to English-language articles.

DATA SYNTHESIS:

Alvimopan is a novel, peripherally acting μ-opioid receptor antagonist that is currently under evaluation for the management of POI. POI presents significant clinical challenges that can delay patient recovery and contribute to increased morbidity and prolonged hospitalization after surgery. Clinical trials have demonstrated that alvimopan, at oral doses of 6 and 12 mg, can accelerate time to recovery of gastrointestinal (GI) function and time to hospital discharge following abdominal surgery. The incidence of adverse events with alvimopan therapy was shown to be similar to that of placebo.

CONCLUSIONS:

Alvimopan is well tolerated and effective at accelerating GI recovery and time to discharge in patients who have undergone bowel resection or hysterectomy when administered prior to surgery and twice daily thereafter until discharge or for up to 7 days. Alvimopan potentially offers significant benefits for patients with POI over currently available treatments.

Pain management for the hospitalized pediatric patient

Pediatric hospitalists should make pain assessment and treatment a high priority and a central part of their daily practice. Efforts at improving pain treatment in pediatric hospitals should be multidisciplinary and should involve combined use of pharmacologic and nonpharmacologic approaches. Although available information can permit effective treatment of pain for most children in hospitals, there is a need for more research on pediatric analgesic pharmacology, various nonpharmacologic treatments, and different models of delivery of care.

Phase III trial of alvimopan, a novel, peripherally acting, mu opioid antagonist, for postoperative ileus after major abdominal surgery

PURPOSE

Postoperative ileus presents significant clinical challenges that potentially prolong hospital stay, contribute to readmission, and increase morbidity. There is no approved treatment for postoperative ileus. Alvimopan is a novel, peripherally acting, mu opioid receptor antagonist currently in development for the management of postoperative ileus.

METHODS

Patients undergoing partial colectomy or simple or radical hysterectomy were randomized to receive alvimopan 6 mg (n = 152), alvimopan 12 mg (n = 146), or placebo (n = 153) orally 2 hours before surgery and twice daily thereafter until discharge or for up to seven days. The primary efficacy end point, time to return of gastrointestinal function, was a composite measure of passage of flatus or stool and tolerating solid food. Secondary end points included time to the hospital discharge order written. Adverse events were monitored throughout the study.

RESULTS

Mean time to gastrointestinal recovery was significantly reduced in patients treated with alvimopan 6 mg vs. placebo (hazard ratio = 1.45; P = 0.003), with a smaller reduction seen with alvimopan 12 mg (hazard ratio = 1.28; P = 0.059). Mean time to the hospital discharge order written was significantly accelerated in patients treated with alvimopan 6 mg (hazard ratio = 1.50; P < 0.001). The most common treatment-emergent adverse events across all treatment groups were nausea, vomiting, and hypotension; the incidence of nausea and vomiting was reduced by 53 percent in the alvimopan 12-mg group.

CONCLUSIONS

In patients undergoing major abdominal surgery, alvimopan accelerated gastrointestinal recovery and time to the hospital discharge order written compared with placebo and was well tolerated.

Adverse Events Associated with Sedatives, Analgesics, and Other Drugs That Provide Patient Comfort in the Intensive Care Unit

Since the 2002 publication of multidisciplinary clinical practice guidelines for intensive care unit (ICU) sedation and analgesia, additional information regarding adverse drug events has been reported. Our understanding of the risks associated with these sedative and analgesic agents promises to improve outcomes by helping clinicians identify and respond to therapeutic misadventures sooner. This review focuses on many issues, including the potentially fatal consequences associated with the propofol infusion syndrome, the evolving understanding of propylene glycol intoxication associated with parenteral lorazepam, new data involving high-dose and long-term dexmedetomidine therapy, haloperidol- and methadone-related prolongation of QTc intervals on the electrocardiogram, adverse events associated with atypical antipsychotics, and the potential for nonsteroidal antiinflammatory drugs to interfere with bone healing.

Alvimopan

Alvimopan is a synthetic peripherally restricted mu-receptor opioid antagonist. Alvimopan has a greater affinity for the mu-receptor than the kappa- or sigma-opioid receptors (Ki = 0.77 nM). The polarity of the molecule limits gastrointestinal absorption and central nervous system penetration. It has limited systemic bioavailability and higher affinity for the mu-opioid receptor than naloxone (Ki = 3.7 nM). Completed Phase III trials suggest efficacy in accelerating the recovery of gastrointestinal function after abdominal surgery. Adverse events with all doses have been similar to placebo groups. Further efficacy in alleviating opioid-induced bowel dysfunction in patients with chronic opioid usage has also been demonstrated. This evidence-based review assesses this new drug and discusses its potential role in clinical practice.

Alvimopan, a selective peripherally acting mu-opioid antagonist

Alvimopan is a novel, peripherally acting mu-opioid antagonist that is being developed for the management of acute postoperative ileus and for the reversal of the delayed gastrointestinal and colonic transit that result in symptoms such as constipation, nausea and motility disorders in patients treated with opiate analgesics. There is a clinical need for effective medications for the treatment of postoperative ileus and opiate-induced constipation and other motility disorders. This review addresses the basic and applied pharmacology and current evidence for the use of the medication, alvimopan, in clinical gastroenterology.

Postoperative pathophysiology and choice of incision

In the few days following major surgical procedures, there are three main physiologic processes which are amenable to surgical management: restoration of fluid and electrolyte homeostasis, management of pain, and attention to gastrointestinal function. New information regarding optimizing the management of these processes is presented, which may accelerate recovery and give improved comfort following abdominal surgery. The type of incision used seems not to be a major factor in such recovery.