Prolonged apnea after remifentanil

A young, healthy adult man exhibited naloxone-reversible, prolonged apnea after a 4-hour infusion of remifentanil, which was used as the opioid component of a general endotracheal anesthetic. Clinical experience and pharmacokinetic simulations indicate that the apnea was clearly atypical.

Subjective effects of additional doses of buprenorphine in patients on buprenorphine maintenance

OBJECTIVES

Buprenorphine has considerable abuse potential. Patients who are maintained on buprenorphine (for opioid dependence) further use additional doses besides its maintenance dose. Subjective effects of the additional doses of buprenorphine in patients on buprenorphine maintenance patients is focused in this study.

METHODS

Nineteen subjects who were maintained on buprenorphine 4mg, s/l per day for at least 1month were admitted and given three additional doses of buprenorphine 2mg, s/l at the interval of 2h each and subjective effects were assessed with the help of standard tools after 2h of each dose and the next day also. Drug was given in a cumulative dose design in the inpatient unit of a de-addiction centre.

RESULTS

Dysphoria and sleepiness increased while euphoria and drug liking decreased with additional doses of buprenorphine. These changes were statistically significant and were highest at maximum cumulative dose of 10mg.

CONCLUSION

Results suggest that abuse liability of buprenorphine in these subjects is low in higher doses. However, these findings need to be replicated in this group of patients to make a comment on clinical implication.

Buprenorphine for the treatment of opioid dependence

PURPOSE

The clinical issues surrounding the use of buprenorphine for the treatment of opioid dependence are reviewed.

SUMMARY

Opioids continue to be some of the most frequently reported prescription medications in substance abuse- related cases. A semisynthetic derivative of thebaine, buprenorphine hydrochloride is a partial mu-opioid receptor agonist and kappa-receptor antagonist with a long duration of action. The pharmacokinetic and pharmacodynamic profiles of buprenorphine are not well characterized. The ethical and legal issues associated with the maintenance treatment of opioid dependence are complex. Clinical trials have compared the efficacy of methadone, buprenorphine, and buprenorphine-naloxone for the detoxification and maintenance treatment of opioid dependence. Based on the available literature, it appears that buprenorphine, buprenorphine-naloxone, and methadone are similarly efficacious for the treatment of opioid-dependent patients. Buprenorphine-naloxone has less potential for abuse and diversion. The adverse-effect profiles for buprenorphine, buprenorphine-naloxone, and methadone are similar. Once-weekly office visits for patient evaluation and dispensing of buprenorphine seem feasible and convenient for both practitioners and patients. The three phases of opioid maintenance treatment are induction, stabilization, and maintenance. It is good practice for the admitting physician to consult with the patient's addiction treatment provider, when possible, to obtain the patient's treatment history.

CONCLUSION

Buprenorphine is an attractive option for the pharmacologic treatment of opioid dependence. Compliance and adherence to buprenorphine therapy for opioid-dependent patients remain clinical issues. Future research efforts should focus on improving compliance and adherence to buprenorphine therapy.

Carbon Dioxide Narcosis and Grand Mal Seizure Complicating Laparoscopic Herniorrhaphy

A 60-year-old man without comorbidity underwent a totally extraperitoneal repair of bilateral inguinal hernias under general anesthesia. Forty minutes after the procedure he developed a slow, shallow respiratory pattern with a respiratory rate of 5/min and a self-limiting grand mal seizure lasting 30 seconds. Arterial blood gas analysis indicated significant hypercarbia and acidosis. The total dose of morphine administered was 20 mg intravenously. Naloxone was administered and the respiratory rate improved. The patient was discharged after 24 hours after making a good recovery and has had no further seizures a year after surgery. Although hypercarbia is a well-known complication of laparoscopic surgery when CO2 is used for insufflation, this, to the best of our knowledge, is the first reported case of a patient sustaining a grand mal seizure resulting from CO2 narcosis after laparoscopic surgery. The possible mechanisms are discussed.

Short-term efficacy of Disulfiram or Naltrexone in reducing positive urinalysis for both cocaine and cocaethylene in cocaine abusers: A pilot study

Cocaine abusers frequently report taking the drug in association with alcohol. This combined intake leads to the synthesis of cocaethylene, an active metabolite with effects similar to those of cocaine, but more prolonged. Since pharmacological effects of cocaethylene may partially account for the habit of cocaine abusers to take the drug in combination with ethanol, a main therapeutic goal in these patients should be making body fluids negative for cocaethylene. This randomized controlled open study conducted on 12 subjects co-abusers of cocaine and alcohol, evaluates the efficacy of a 12-week pharmacological treatment with Disulfiram (DIS) 400mg daily or Naltrexone (NTX) 50mg daily associated with Cognitive Behaviour Therapy (CBT), as compared to CBT alone, in terms of: (i) stay in treatment; (ii) drug-free urinalyses for cocaine and cocaethylene; (iii) reduction of alcohol and cocaine craving. Data presented in this study are restricted to the first 4 weeks of treatment when all the enrolled subjects were still available for examination. In fact, of the 12 subjects enrolled in the study only 4 (33%) completed the 12-week treatment. Of these, three were in the CBT group and one in the NTX/CBT group. Results show that CBT treated subjects remained in treatment longer than those assigned to either DIS/CBT or NTX/CBT therapies. However, during the first 4 weeks of treatment, CBT-group urine tested positive almost always for both cocaine and cocaethylene. In contrast, both DIS/CBT and NTX/CBT treatments were associated to a statistically significant reduction, of positive urinalysis for both cocaine and cocaethylene, with respect to CBT alone. Moreover, across the first 4 weeks of treatment DIS/CBT and NTX/CBT treated subjects maintained lower scores at Visual Analogue Scales (VAS) for both cocaine and alcohol craving than subjects receiving CBT alone. This pilot study suggests that the transient efficacy of pharmacological treatments in maintaining subjects drug free, does not add to the capability of CBT to retain them in treatment.

Experimentally induced aggressiveness in heroin-dependent patients treated with buprenorphine: comparison of patients receiving methadone and healthy subjects

Objective measures of experimentally induced aggressiveness were evaluated in heroin-dependent patients (HDP), 15 receiving buprenorphine (BUP) and 15 receiving methadone (METH) treatment. HDP were randomly assigned to BUP and METH groups. Fifteen healthy subjects (CONT) were included in the study as controls. During a laboratory task, the Point Subtraction Aggression Paradigm, subjects earned monetary reinforcement and could respond by ostensibly subtracting money from a fictitious subject (the aggressive response). Money-earning (points maintained) responses did not differ in BUP patients and in controls. In contrast, point-maintained responses were significantly lower in the group of HDP treated with METH than in both the BUP and CONT groups. Aggressive responses were significantly higher in the HDP group than in the CONT group. No significant differences in aggressive responses were found between the BUP and METH groups. Baseline concentrations of plasma adrenocorticotropic hormone (ACTH) and cortisol (CORT) were higher in HDP than in CONT. During the experimental task, ACTH and CORT increased significantly less in METH patients than in BUP patients and CONT. Norepinephrine (NE) and epinephrine (EPI) levels increased significantly more in HDP than in CONT, without any difference between the METH and BUP patients. PSAP aggressive responses positively correlated with NE and EPI changes, as well as with Buss-Durkee Hostility Inventory (BDHI) scores in both METH and BUP patients and also in CONT subjects. No correlation was found between the extent of heroin exposure, drug doses and aggressiveness levels. BUP, similarly to METH, does not seem to affect outward-directed aggressiveness, as aggressive responses related more to monoamine levels and personality traits than to the action of opioid agonists. Money-earning responses seemed to be unimpaired in BUP patients.

Evaluation of the use of buprenorphine for opioid withdrawal in an emergency department

OBJECTIVES

To examine the use of buprenorphine for the treatment of opioid withdrawal (OW) in an emergency department (ED) setting.

METHODS

The medical records of all adult patients who presented to the study ED during a 10 week period for OW were abstracted. Subjects were categorized as receiving buprenorphine, symptomatic treatment or no pharmacologic treatment for their OW. The three groups were compared by patient and service characteristics, withdrawal symptoms and outcomes.

RESULTS

Of the 11,019 patients who presented to the ED during the 10 week study period, 158 (1.4%) were eligible. Subjects were more likely to receive buprenorphine (56%) compared to symptomatic treatment only (26%) or no pharmacologic treatment (18%). Subjects who received buprenorphine were more likely to have a history of suicide ideation (34% versus 12% p<0.05) compared to subjects who received symptomatic treatment(s) and were less likely to present with a gastrointestinal complaint (9% versus 25% p<0.05). Subjects who received buprenorphine were less likely to return to the same ED within 30 days for a drug-related visit (8%) compared to those who received symptomatic treatment (17%) (p<0.05).

CONCLUSIONS

Buprenorphine was a common treatment for OW in this ED without any documented adverse outcomes. Given that it did not result in an increase in drug-related return ED visits and its proven efficacy in other settings, a prospective evaluation of its potential value to ED patients who present with OW is warranted.

Extended-release intramuscular naltrexone

An extended-release intramuscular formulation of naltrexone that provides sustained release of the drug over a 28-day period has been developed with the aim of improving treatment adherence in patients treated with naltrexone for alcohol dependence. Biodegradable polylactide-co-glycolide polymer microspheres containing 34% w/w naltrexone are reconstituted in an aqueous suspension just prior to intramuscular administration. Extended-release intramuscular naltrexone 380 mg administered once every 4 weeks, in combination with psychosocial therapy, demonstrated superior efficacy to placebo plus psychosocial therapy in reducing the heavy drinking event rate (primary endpoint) in adult patients with alcohol dependence in a 6-month well controlled trial. Among the subset of patients who abstained completely from drinking during the 7 days prior to the first dose of medication (n = 53; 8% of the total study population), those treated with extended-release intramuscular naltrexone 380 mg had greater reductions in the number of drinking days and the number of heavy drinking days compared with placebo recipients. Treatment with extended-release intramuscular naltrexone 380 mg once every 4 weeks for up to 18 months was generally well tolerated, with infrequent treatment-related serious adverse events. The most common treatment-emergent adverse events leading to treatment discontinuation were nausea, injection site reaction and headache. The proportion of patients with clinically significant plasma transaminase elevations was not different between patients receiving extended-release intramuscular naltrexone and those receiving placebo.

Efficacy of naltrexone in smoking cessation: a preliminary study and an examination of sex differences

This double-blinded, placebo-controlled trial evaluated the efficacy of naltrexone as an adjunct to standard smoking cessation treatment. Participants (N = 110) were adult male and female nicotine-dependent smokers who expressed interest in quitting smoking. All subjects received six sessions of behavioral counseling (1 hr/session for 6 weeks), and 1 month of the nicotine patch (21 mg for the first 2 weeks, 14 mg the third week, 7 mg the fourth week). Subjects were randomly assigned to the naltrexone or placebo group. The naltrexone group started at 25 mg daily for 3 days prior to the quit date, and increased to 50 mg/day on the quit date and following 8 weeks. At the end of medication treatment, the naltrexone group had better quit rates versus the placebo group (48% quit on naltrexone vs. 41% on placebo), but this difference was not statistically significant. However, men and women differed on several measures: in the placebo group, women had significantly lower quit rates than men (39% vs. 67%, p<.05), but in the naltrexone group, women had quit rates comparable with those of men (58% vs. 62%, p = ns). Further examination revealed that naltrexone significantly reduced men's and women's cessation-related weight gain and selectively reduced women's urge to smoke to relieve negative affect and withdrawal. The results suggest continued examination of naltrexone as an adjunct in smoking cessation, particularly in female smokers, who have historically shown worse outcomes with traditional treatment methods.

Naltrexone accelerates healing without compromise of adhesion complexes in normal and diabetic corneal epithelium

Naltrexone (NTX) is an opioid antagonist that accelerates wound healing of corneal epithelium in normal and diabetic animals. Junctional complexes (hemidesmosomes) are important in establishing adhesion of the corneal epithelium to the stroma. This study was designed to examine whether NTX, at a concentration that enhances corneal re-epithelialization, influences the appearance and number of hemidesmosomes in Normal, diabetic (DB) (hyperglycemic), and DB animals receiving insulin (DB-IN) (normoglycemic), and treated topically with NTX (10(-4) M) or sterile vehicle (SV) for 7 days following abrasion. Electron microscopic analysis of the peripheral cornea 2 weeks after removal of the epithelium indicated hemidesmosomes that could be classified into four sectional profiles. No differences were detected in either the structure or the number of junctional complexes in the cornea between Normal, DB, or DB-IN groups receiving vehicle or treated with NTX. Moreover, the fine structure of the basal and suprabasal layers of the corneal epithelium in all groups--including those treated with NTX--were comparable. These results indicate that topical application of NTX accelerates diabetic corneal epithelial healing without causing morphologic abnormalities in the reassembly of adhesion structures. Furthermore, controlled and uncontrolled diabetes for up to 3 months does not affect corneal adhesion complexes when compared to normal corneas. Thus, recurrent erosion following abrasion of the diabetic cornea, with preservation of the basal lamina, cannot be explained by structural abnormalities in the reformation of the epithelial adhesion complex.

Hepatitis C virus eradication in intravenous drug users maintained with subcutaneous naltrexone implants

The effectiveness of HCV antiviral therapy in patients who have undergone recent drug dependency treatment and continue to inject drugs sporadically is presently not clear. Patients attending a community-based drug rehabilitation and naltrexone implant clinic from October 2002 until March 2005 were screened for HCV infection and if positive offered further assessment and treatment with interferon and ribavirin therapy. The first 50 patients to commence HCV therapy and complete at least 6 months follow-up were prospectively studied. ETR response (HCV PCR negative) was 34/50 (68%) and SVR 6 months post-treatment was 31/50 (62%). Viral eradication was maintained in those 22 patients that have had 12 months or more post-treatment follow-up. Eleven (22%) patients stopped therapy early due to side effects or poor compliance. Only two patients with an ETR likely reinfected due to unsafe injection practices. One was re-treated and achieved an SVR. Of the patients achieving a 6-month SVR, 17 of 31 patients reported no further IDU and 13 of 31 patients occasional IDU during treatment and this was maintained after HCV treatment cessation. 46% of patients received antidepressant and/or antipsychotic medication during treatment.

CONCLUSION

This study of HCV treatment in a community-based subcutaneous naltrexone implant clinic found antiviral therapy resulted in a 62% SVR. This result is comparable to that reported in hospital-based clinics in non-IDU patients. The side effect profile and compliance was also similar. HCV antiviral therapy should be offered to this large and currently under treated group.

Monitored Naltrexone without Counseling for Alcohol Abuse/Dependence in Schizophrenia-Spectrum Disorders

This clinical trial assessed the effects of monitored naltrexone treatment in 19 subjects with schizophrenia spectrum and alcohol use disorders in an eight-week prospective open pilot study. Naltrexone was directly administered to subjects in oral doses of 100 mg on Mondays and Wednesdays, and 150 mg on Fridays. Subjects received reimbursement for attending the three weekly study visits. Subjects continued to receive their usual psychiatric care with no added alcohol counseling provided. Alcohol use was assessed by self-report and biomarkers. Psychosis severity was measured by the Positive and Negative Syndrome Scale (PANSS). Subjects reported significant reductions in their number of drinks per week, drinks per drinking day, days of drinking to intoxication, and alcohol craving. Subjects also showed significant reductions in Addiction Severity Index (ASI) alcohol composite scores and in PANSS positive, negative and general psychopathology scores.

Naltrexone-assisted rapid methadone discontinuation: a pilot study

Slow downtitration as a methadone discontinuation method is time-consuming and associated to high dropout rates. Whereas ultra-rapid opiate detoxification methods have recently gained some popularity, they are expensive and may be associated with particular problems in methadone patients. In the present study, a 3-day detoxification procedure accelerated with a unique dose of naltrexone was used in 10 methadone-substituted patients. Whereas the treatment resulted in a shortened withdrawal syndrome, which was satisfactorily controlled by the drugs used, a two-phase course was observed, some symptoms reappearing between the end of day 2 and the beginning of day 3. The first phase of withdrawal symptoms was attributed to the antagonistic effect of naltrexone, which possibly also improved under the weakening of naltrexone. The second phase of withdrawal symptoms may be related to falling methadone plasma levels.

Prooxidative/antioxidative homeostasis in heroin addiction and detoxification

BACKGROUND

Long-term heroin abuse is related to pathological changes in many organs mediated by oxidative stress (OS).

OBJECTIVES

Estimation of systemic OS and antioxidant capacity in heroin addiction and detoxification provides information about prooxidant/antioxidant homeostasis in heroin misuse and need for antioxidant supplementation.

METHODS

OS was evaluated by the measurement of plasma reactive oxygen metabolites using spectrophotometric method and plasma lipid peroxidation by its end product--malondyaldehyd using Tiobarbituric Acid Reactions Substances method. The extracellular antioxidant capacity was estimated using OXY-adsorbent test.

RESULTS

This cross-sectional study includes 68 patients: 46 heroin addicts (20 patients on chronic heroin abuse, 19 patients on conventional method of detoxification and 7 patients on opioid antagonist--naltrexone (and 22 patients as a control) group. Increased OS was found in the heroin group (d-ROMs 349.3 +/- 102.2 UCarr, MDA 4.0 +/- 0.4 micromol/L) compared to the group on detoxification (d-ROMs 230.2 +/- 96.4 UCarr; MDA 3.6 +/- 0.3 micromol/L) and control group (d-ROMs 264.1 +/- 30.9 UCarr; MDA 3.7 +/- 0.2 micromol/L). TAC was decreased in the heroin group (324.5 +/- 75.0 micromol HClO/ml) and restored during conventional detoxification (371.8 +/- 25.1 micromol HClO/ml), but not completely in the group with naltrexone treatment (335.6 +/- 16.9 micromol HClO/ml) compared with controls (395.4 +/- 35.6 micromol HClO/ml).

CONCLUSION

Long-term heroin abuse stimulates a progressive systemic oxidative stress which increases the extracellular antioxidants consumption and develops conditions for chronic heroin toxicity (Fig. 1, Tab. 4, Ref. 35). Full Text (Free, PDF) www.bmj.sk.

[Self-administration of intravenous drugs--a rare cause of respiratory arrest in medical practice]

Respiratory arrest is a major emergency in medical practice, which implies prompt intervention from the physician assisting such case. Respiratory arrest can be classified into primary respiratory arrest, caused by airway obstruction, decreased respiratory drive, or respiratory muscle weakness and secondary respiratory arrest, as a result of circulatory insufficiency. Among important causes of respiratory arrest, acute poisonings are to remember. We present a case of respiratory arrest following intravenously self-administration of opiates in attempted suicide. Patient required rapidly orientated etiologic diagnostic, and had a favorable outcome, with complete recovery, after applying CPR protocol, as well as antidote.

The Partial 5-Hydroxytryptamine1A Receptor Agonist Buspirone does not Antagonize Morphine-induced Respiratory Depression in Humans

Based on experiments in rats, serotonin receptor 5-hydroxytryptamine (5-HT)(1A) agonists have been proposed as a potential therapeutic strategy for the selective treatment of opioid-induced respiratory depression. We investigated the clinical applicability of this principle in healthy volunteers. Twelve subjects received 0.43 mg/kg morphine (30 mg for 70 kg body weight) administered intravenously (i.v.) over approximately 2 h. At the start of the morphine infusion, they received in a randomized, double-blind cross-over design 60 mg p.o. buspirone or placebo. Respiratory depression (hypercapnic challenge) and pain (electrical stimuli: 5 Hz sinus 0-20 mA; chemical stimuli: 200 ms gaseous CO(2) pulses applied to the nasal mucosa) were assessed at baseline, at the end of the morphine infusion, and a third time after antagonizing the opioid effects by i.v. administration of 2 mg naloxone. The linear relationship between the minute ventilation and the CO(2) concentration in the inspired air of 1.07+/-0.27 l/mm Hg CO(2) at baseline conditions became shallower (0.45+/-0.23 l/mm Hg CO(2)) after morphine administration (P<0.001), indicating respiratory depression, which was significantly reversed by naloxone (0.95+/-0.43 l/mm Hg CO(2); P=0.001). Co-administration of buspirone had no effect on morphine-induced respiratory depression (slope 0.45+/-0.23 l/mm Hg CO(2) under morphine plus placebo versus 0.38+/-0.25 l/mm Hg CO(2) under morphine plus buspirone; P=0.7). Significant morphine-induced analgesia was observed in both pain models and was reversed by naloxone but unaffected by buspirone. Buspirone significantly increased the nausea induced by morphine (P=0.011). Oral co-administration of a high dose of the clinically available 5-HT(1A) agonist buspirone cannot be advised as a remedy for opioid-induced respiratory depression. This is indicated by its lack of anti-respiratory depressive effects and by the buspirone-associated increase of morphine-induced nausea.

Buprenorphine reduces alcohol drinking through activation of the nociceptin/orphanin FQ-NOP receptor system

BACKGROUND

Activation of the NOP receptor by its endogenous ligand nociceptin/orphanin FQ reduces ethanol intake in genetically selected alcohol preferring Marchigian Sardinian alcohol preferring (msP) rats. Here we evaluated whether buprenorphine, a partial agonist at micro-opioid and NOP receptors, would reduce ethanol consumption in msP rats via activation of NOP receptors.

METHODS

Marchigian Sardinian alcohol preferring rats trained to drink 10% alcohol 2 hours/day were injected with buprenorphine (.03, .3, 3.0, or 6.0 mg/kg intraperitoneally [IP]) 90 min before access to ethanol.

RESULTS

Similar to prototypical micro-agonists, the two lowest doses of buprenorphine significantly increased ethanol consumption (p < .01); in contrast, the two highest doses reduced it (p < .05). Pretreatment with naltrexone (.25 mg/kg IP) prevented the increase of ethanol intake induced by .03 mg/kg of buprenorphine (p < .001) but did not affect the inhibition of ethanol drinking induced by 3.0 mg/kg of buprenorphine. Conversely, pretreatment with the selective NOP receptor antagonist UFP-101 (10.0 or 20.0 microg/rat) abolished the suppression of ethanol drinking by 3.0 mg/kg of buprenorphine.

CONCLUSIONS

Buprenorphine has dualistic effects on ethanol drinking; low doses increase alcohol intake via stimulation of classic opioid receptors, whereas higher doses reduce it via activation of NOP receptors. We suggest that NOP agonistic properties of buprenorphine might be useful in the treatment of alcoholism.

Neurobiologische Mechanismen und Pharmakologische Behandlungsansätze des Alkohol-Craving

In the last years, numerous studies have been performed on neurobiological mechanisms in alcohol craving. Changes in the hypothalamic cortisol pathway and the leptin metabolism, which is also associated with pharmacological interventions, have been of special interest. With acamprosate and naltrexone two substances exist for pharmacotherapy, but recent results about the efficacy are controversial. The clinical profit of disulfiram has been shown, at least in a subgroup of patients. Besides, there are several promising candidate substances. Current investigations focus on a differentiated pharmacotherapy of alcohol dependence, including psychological and genetic factors.

Physicians' knowledge of and willingness to prescribe naloxone to reverse accidental opiate overdose: challenges and opportunities

Naloxone, the standard treatment for heroin overdose, is a safe and effective prescription drug commonly administered by emergency room physicians or first responders acting under standing orders of physicians. High rates of overdose deaths and widely accepted evidence that witnesses of heroin overdose are often unwilling or unable to call 9-1-1 has led to interventions in several US cities and abroad in which drug users are instructed in overdose rescue techniques and provided a "take-home" dose of naloxone. Under current Food and Drug Administration (FDA) regulations, such interventions require physician involvement. As part of a larger study to evaluate the knowledge and attitudes of doctors towards providing drug treatment and harm reduction services to injection drug users (IDUs), we investigated physician knowledge and willingness to prescribe naloxone. Less than one in four of the respondents in our sample reported having heard of naloxone prescription as an intervention to prevent opiate overdose, and the majority reported that they would never consider prescribing the agent and explaining its application to a patient. Factors predicting a favorable attitude towards prescribing naloxone included fewer negative perceptions of IDUs, assigning less importance to peer and community pressure not to treat IDUs, and increased confidence in ability to provide meaningful treatment to IDUs. Our data suggest that steps to promote naloxone distribution programs should include physician education about evidence-based harm minimization schemes, broader support for such initiatives by professional organizations, and policy reform to alleviate medicolegal concerns associated with naloxone prescription. FDA re-classification of naloxone for over-the-counter sales and promotion of nasal-delivery mechanism for this agent should be explored.

Novel opioid antagonists for opioid-induced bowel dysfunction and postoperative ileus

Methylnaltrexone and alvimopan are two new and potentially useful agents in the management of opioid-induced bowel dysfunction and prevention of postoperative ileus. Both agents have promising prokinetic properties and appear to be capable of reversing the effects of opioids on delayed gastrointestinal transit. This article reviews currently available published literature to provide an overview of the clinical trials and to provide insight for the potential use of these agents for patients requiring opioid based analgesia. These compounds represent a new class of compounds that may impact the therapeutics for opioid induced bowel dysfunction as well as postoperative ileus.