Opioids and the gastrointestinal tract - a case of narcotic bowel syndrome and literature review

Recent advances in the opioid mu receptor based pharmacotherapy for rheumatoid arthritis

INTRODUCTION

Opioids are used for severe forms of acute and cancer pain. Over the last years, their potential use in patients with noncancer pain such as those with rheumatoid arthritis (RA) has been postulated. A recent population-based comparative study showed that chronic opioid use was 12% vs. 4% among RA and non-RA patients, respectively. Another study showed an increase from 7.4% to 16.9% (2002 to 2015). In general, there has been an increasing tendency to use opioids in recent years.

AREAS COVERED

The authors have performed an extensive literature search using PubMed for articles including noncancer pain and the use of the mu opioid receptor (MOR) agonists in patients with RA.

EXPERT OPINION

Data is not sufficient to support opioid use for the treatment of chronic pain in patients with RA. Data is scarce and inconclusive. Rheumatologists should think and ponder the question: Why is this patient in pain? Differential diagnosis should include a disease flare, degenerative changes of the musculoskeletal system, and fibromyalgia. And while there are new strategies for opioid administration currently being researched, unfortunately, they are far from being applied to human subjects in the everyday clinical setting, and are still being evaluated at an experimental level. CNS: Central nervous system; DORs: delta opioid receptor agonists; GI: Gastrointestinal; GPCRs: G protein-coupled receptors; IL: Interleukin; JAK: Janus kinase; KORs: kappa opioid receptor agonists; MCPs: Metacarpophalangeal joints; MORs: Mu opioid receptor agonists; MTPs: Metatarsophalangeal joints; NSAIDs: Non-steroidal anti-inflammatory drugsOA: Osteoarthritis; ORs: Opioid receptors; PD: Pharmacodynamic; PIPs: Proximal interphalangeal joints; PK: Pharmacokinetic; PNS: Peripheral nervous system; RA: Rheumatoid arthritis; RGS: Regulator of G protein signaling; SSRIs: Selective serotonin reuptake inhibitors; TNF: Tumor necrosis factor.

Cardiovascular phenotyping for personalized lifestyle treatments of chronic abdominal pain in Irritable Bowel Syndrome: A randomized pilot study

BACKGROUND

Different physical exercise interventions for pain and other related symptoms largely follow non-personalized guidelines and show a high degree of variability in outcome. These interventions are considered to have different pathways toward improvement in autonomic regulation of energy metabolism. The current pilot study was conducted to assess the predictive value of individual cardiovascular (CV) activity markers at rest to predict clinical outcomes for two popular exercise-based interventions (walking and yoga) in patients with Irritable Bowel Syndrome (IBS).

METHODS

Twenty-seven adult participants with IBS were randomly assigned to a 16-biweekly Iyengar yoga or walking program. They completed pre- and post-treatment assessments on IBS symptom severity, affective and somatic complaints, and various measures of resting autonomic function including blood pressure (BP), heart rate and its variability, baroreceptor sensitivity (BRS) to activations and inhibitions with gains of brady- and tachycardiac baro-responses, and BP start points for these spontaneous baroreflexes.

RESULTS

Pretreatment BRS was differentially related to clinical response for the treatment groups. Specifically, a significant decrease in pain severity was found in response to yoga for those participants who had lower resting BRS to activations, but decreased pain severity was associated with higher resting BRS for those in the walking group. The effect was not related to affective symptom relief. Other CV measures showed similar associations with clinical outcomes for both groups.

CONCLUSIONS

The data suggest therefore that CV based phenotypes may be useful in personalizing clinical interventions for IBS. They may also point to autonomic mechanisms that are targets for such interventions.

Opioid misuse in gastroenterology and non-opioid management of abdominal pain

Opioids were one of the earliest classes of medications used for pain across a variety of conditions, but morbidity and mortality have been increasingly associated with their chronic use. Despite these negative consequences, chronic opioid use is increasing worldwide, with the USA and Canada having the highest rates. Chronic opioid use for noncancer pain can have particularly negative effects in the gastrointestinal and central nervous systems, including opioid-induced constipation, narcotic bowel syndrome, worsening psychopathology and addiction. This Review summarizes the evidence of opioid misuse in gastroenterology, including the lack of evidence of a benefit from these drugs, as well as the risk of harm and negative consequences of opioid use relative to the brain-gut axis. Guidelines for opioid management and alternative pharmacological and nonpharmacological strategies for pain management in patients with gastrointestinal disorders are also discussed. As chronic pain is complex and involves emotional and social factors, a multimodal approach targeting both pain intensity and quality of life is best.

Opioid Medications in the Management of Chronic Abdominal Pain

PURPOSE OF REVIEW

Chronic abdominal pain is a complex medical condition. The causes of chronic abdominal pain are extremely diverse ranging from chronic pancreatitis, Crohn's disease, to chronic pain with no clear etiology. Treatment of chronic abdominal pain remains a challenge in our clinical practice. While current interventions with celiac plexus blocks and pain medications provide some relief for these patients, but these treatments are typically less efficacious and limited by various adverse effects. Opioid medications are commonly used to manage chronic pain syndromes that are refectory to other pain management interventions. The potential problems related to opioids include misuse, abuse, constipation, nausea pruritus, et al. Moreover, according to the recent centers for disease (CDC) control report, opioid abuse has reached epidemic proportions in the USA (LJ P. Centers for Disease Control and Prevention. 2016) and accounted for 28,000 deaths in 2014. Rudd et al. (MMWR Morb Mortal Wkly Rep 64(50-51):1378-82, 2016) Given this current situation, it is apparent that a careful review of clinical evidences supporting the use of opioid medications is necessary to guide our treatment approaches in the management of complex chronic abdominal pain patients. This review is set out to analyze efficacy of opioid medications for chronic abdominal pain.

RECENT FINDINGS

The literature referenced was obtained via a computer search with Google Scholar, Pubmed, Medline, and EMbase. The search terms used included Opioid, Oxycodone, Buprenorphine, Morphine, Fentanyl, Oxymorphone, Hydromorphone, chronic abdominal pain, Crohn's disease, and pancreatitis. All studies were considered eligible for inclusion if they were clinical studies evaluating the efficacy of opioid medications for chronic abdominal pain. Two studies were found according to these criteria. Chronic abdominal pain is a challenging medical condition in our daily practice. This condition often requires opioid medications when other treatments fail. This review provided very limited clinical evidence to support long-term opioid use for chronic abdominal pain. Given recent CDC report of opioid epidemic, it is prudent to use the best medical practice with appropriate evaluation of psychological comorbidities, urine drug screening, prescription drug monitor, and opioid treatment agreements to minimize adverse side effects related to opioids. Furthermore, well-designed clinical trials are needed to evaluate the effectiveness of long-term use of opioid medications, and more clinical research on which opioid medication is more effective for chronic abdominal pain.

Gastrointestinal disorders in joint hypermobility syndrome/Ehlers-Danlos syndrome hypermobility type: A review for the gastroenterologist

BACKGROUND

Joint hypermobility syndrome (JHS)/Ehlers-Danlos syndrome hypermobility type (EDS-HT) is the most common hereditary non-inflammatory disorder of connective tissue, characterized by a wide range of symptoms, mainly joint hyperextensibility and musculoskeletal symptoms. A majority of patients also experiences gastrointestinal (GI) symptoms. Furthermore, JHS/EDS-HT has specifically been shown to be highly prevalent in patients with functional GI disorders, such as functional dyspepsia and irritable bowel syndrome.

PURPOSE

The aim of this review was to examine the nature of GI symptoms and their underlying pathophysiology in JHS/EDS-HT. In addition, we consider the clinical implications of the diagnosis and treatment of JHS/EDS-HT for practicing clinicians in gastroenterology. Observations summarized in this review may furthermore represent the first step toward the identification of a new pathophysiological basis for a substantial subgroup of patients with functional GI disorders.

Management of chronic visceral pain

Despite marked differences in underlying pathophysiology, the current management of visceral pain largely follows the guidelines derived from the somatic pain literature. The effective management of patients with chronic visceral pain should be multifaceted, including both pharmacological and psychological interventions, thereby providing a mechanism-orientated approach to treatment. Patients can frequently become disenfranchised, and subsequently disengaged, with healthcare providers leading to repeated consultations. Thus, a key aspect of management is to break this cycle by validating patients' symptoms, adopting an empathic approach and taking time to educate patients. To optimize treatment and outcomes in chronic visceral pain we need to move away from approaches exclusively based on dealing with peripheral nociceptive input toward more holistic strategies, taking into account alterations in central pain processing.

The narcotic bowel syndrome: a recent update

OBJECTIVES

The paradoxical development of chronic abdominal pain is an underrecognized side effect of opioid use. Narcotic bowel syndrome (NBS), occurring in a small proportion of chronic opioid users, consists of chronic or intermittent abdominal pain, which often increases in severity despite continued or escalating dosages of opioids prescribed to relieve pain.

METHODS

A PubMed search was conducted using terms such as "narcotic bowel syndrome" and "opioid hyperalgesia" through January 2014.

RESULTS

Abdominal pain is the defining symptom of NBS and is thought to be mediated by central nervous system dysfunction; it should be distinguished from the peripheral side effects of opioids, such as nausea, bloating, intermittent vomiting, abdominal distension, and constipation. This latter cluster of symptoms is called opioid bowel dysfunction, although it may co-occur with NBS. Hypothesized mechanisms of the central effects of opioids on nociception in NBS include spinal cord inflammation and dysfunction in opioid receptor activity and related neuroanatomical substrates. With continued use, ∼6% of patients taking narcotics chronically will develop NBS, with profound consequences in terms of daily function. The primary management paradigm for NBS is a structured opioid withdrawal program accompanied by centrally acting adjunctive therapy comprising antidepressants, benzodiazepines, and clonidine to target pain, anxiety, and depression, and prevent withdrawal effects, in addition to peripherally acting agents such as laxatives (e.g., osmotic laxatives and chloride channel activators) to control transient constipation. Such structured withdrawal programs have been prospectively evaluated in small clinical trials and have met with considerable success in the short term.

CONCLUSIONS

Because rates of NBS are likely to rise, integrated intensive pharmacotherapy and psychosocial interventions are needed to help patients with NBS go off and stay off opioids. These programs will likely also reduce comorbid psychopathology and lead to adequate pain control and improved quality of life.

Centrally Mediated Disorders of Gastrointestinal Pain

Centrally Mediated Abdominal Pain Syndrome (CAPS), formerly known as Functional Abdominal Pain Syndrome, can be distinguished from other functional GI disorders by its strong central component and relative independence from motility disturbances. CAPS is a result of central sensitization with disinhibition of pain signals rather than increased peripheral afferent excitability. A newly described condition, Narcotic Bowel Syndrome (NBS)/Opioid-Induced GI Hyperalgesia, is characterized by the paradoxical development of or increases in abdominal pain associated with continuous or increasing dosages of opioids. Patients only have relief when opioids are withdrawn. We define both conditions in the context of epidemiology, pathophysiology, clinical evaluation and treatment, emphasizing the importance of a physician-patient relationship in all aspects of care.

Intestinal inflammation and pain management

Intestinal inflammation results in the production of inflammatory pain-inducing mediators that may directly activate colon sensory neurons. Endogenous opioids produced by mucosal effector CD4(+) T lymphocytes identified as colitogenic may paradoxically counterbalance the local pro-algesic effect of inflammatory mediators by acting on opioid receptors expressed on sensory nerve endings. The review will focus on the endogenous immune-mediated regulation of visceral inflammatory pain, current pain treatments in inflammatory bowel diseases and prospectives on new opioid therapeutic opportunities to alleviate pain but avoiding common centrally-mediated side effects.

Avoiding analgesic escalation and excessive healthcare utilization in severe irritable bowel syndrome: a role for intramuscular anticholinergics?

OBJECTIVES

In patients with severe irritable bowel syndrome (IBS), abdominal pain can be the predominant symptom impacting on all aspects of their lives and resulting in excessive healthcare utilization. Furthermore, the use of analgesics can become excessive in this group of patients, sometimes leading to opiate dependency. Typically, the pain is often described as spastic in nature and we have speculated that parenteral anticholinergics might provide effective relief when all other measures have failed. For several years, we have therefore been asking general practitioners to consider teaching such patients to administer intramuscular hyoscine butylbromide for pain episodes and this study is an audit of this approach.

METHODS

Patients in whom the use of intramuscular hyoscine butylbromide had been recommended to their general practitioner in the last three years were interviewed over the telephone in order to document the efficacy of this approach as well as any potential disadvantages.

RESULTS

A total of 122 general practitioners were advised to try this approach, with 58 agreeing to teach the technique and prescribe the medication. Of the 58 patients who used the medication, 50 (86%) found it gave them pain relief, which was complete in six (10%), substantial in 36 (62%) and mild in eight (14%), with 15 (26%) decreasing the use of analgesics and 13 (32%) of the 41 taking opiates able to reduce or stop them completely. Side effects were few and largely consisted of those associated with anticholinergics. Only four patients stopped medication because of side effects and no major skin reactions were reported.

CONCLUSIONS

The use of intramuscular hyoscine butylbromide shows promise in the management of IBS when severe unmanageable abdominal pain is a major problem. This approach appears to be safe and has the potential to reduce analgesic escalation, opiate dependency and attendances at accident and emergency departments.

Narcotic bowel syndrome and opioid-induced constipation

Prescription opioid use for chronic non-cancer pain has reached epidemic levels in the USA. With this increased use is the recognition of serious opioid-related gastrointestinal complications such as narcotic bowel syndrome (NBS) and opioid-induced constipation (OIC). NBS consists of a paradoxical worsening of abdominal pain with escalating doses of opioids and is likely mediated by the central nervous system. Therapy requires an intensive multidisciplinary approach to detoxification. OIC is the most common gastrointestinal side effect of opioids. Several novel therapeutics are available to treat OIC that fails to respond to laxative therapy. This review will summarize recent findings on the pathophysiology and treatment approaches to NBS and OIC with a focus on controversies about diagnosis and intervention.

Prevalence of narcotic bowel syndrome in opioid abusers in iran

BACKGROUND In spite of the increasing trend in opioid abusers worldwide, the prevalence of narcotic bowel syndrome (NBS) is undetermined. We aimed to estimate the prevalence of NBS and other opioid bowel dysfunction (OBD) in opioid abusers in Kerman, southeast Iran. According to the best of our knowledge, this is the first study to assess the prevalence of NBS in opioid abusers. METHODS By referring to addiction treatment centers in Kerman city and in a cross-sectional study, 577 subjects with opium or opioid subtracts abuse were included in our study. A validated questionnaire was used for OBD assessment and diagnosis of NBS was made according to both the presence of chronic abdominal pain despite increasing the opioid dose and ruling out other causes of abdominal pain. SPSS software version 16 was used for data analysis. p value<0.05 was considered as statistically significant. RESULTS Constipation, regurgitation, and heartburn were the most gastrointestinal complaints that were found in 132(22.9%), 123(21.3%) and 91(15.8%) subjects, respectively. Only 16(2.8%) participants fulfilled all the NBS criteria. Simultaneous use of non-narcotic sedative drugs increased the risk of NBS significantly (the odds ratio 3:1 and p=0.049). CONCLUSION NBS is not rare among opioid abusers and should be considered as a cause of chronic abdominal pain in this group.

Mechanisms and management of functional abdominal pain

Functional abdominal pain syndrome is characterised by frequent or continuous abdominal pain associated with a degree of loss of daily activity. It has a reported population prevalence of between 0.5% and 1.7%, with a female preponderance. The pathophysiology of functional abdominal pain is incompletely understood although it has been postulated that peripheral sensitisation of visceral afferents, central sensitisation of the spinal dorsal horn and aberrancies within descending modulatory systems may have an important role. The management of patients with functional abdominal pain requires a tailored multidisciplinary approach in a supportive and empathetic environment in order to develop an effective therapeutic relationship. Patient education directed towards an explanation of the pathophysiology of functional abdominal pain is in our opinion a prerequisite step and provides the rationale for the introduction of interventions. Interventions can usefully be categorised into general measures, pharmacotherapy, psychological interventions and 'step-up' treatments. Pharmacotherapeutic/step-up options include tricyclic antidepressants, serotonin noradrenergic reuptake inhibitors and the gabapentinoids. Psychological treatments include cognitive behavioural therapy and hypnotherapy. However, the objective evidence base for these interventions is largely derived from other chronic pain syndrome, and further research is warranted in adult patients with functional abdominal pain.

Pre-operative opioid analgesia reduces clinical success of laparoscopic gastric electrical stimulation placement in patients with gastroparesis

INTRODUCTION

Gastroparesis is a common chronic and costly disorder for which medical therapy is often unsuccessful. Gastric electrical stimulation (GES) has been used to treat refractory cases, however, response is variable and difficult to predict. This study aims to assess whether pre-operative opioid analgesics (OA) use affects clinical success of GES.

METHODS

Records of 128 patients who underwent laparoscopic GES placement from March 2001 to September 2012 were analyzed retrospectively. Data collected included demographics, surgical outcomes, and clinical parameters. Pre- and post-operative opioid analgesic dosing (No = 0 morphine equivalents (ME)/day, Low = 0-40 ME/day, Mid = 41-80 ME/day, High >80 ME/day), as well as clinical symptom assessment was collected for up to 3 years post-operatively. Clinical success was defined as (1) OA reduction of >50 %, (2) maintenance of weight, or (3) symptom improvement. Descriptive statistics were computed for all factors. A p < 0.05 was considered statistically significant.

RESULTS

Fifty-three patients were on OA pre-operatively compared to 69 patients who were not. Patients not on OA pre-operatively were less likely than those on OA pre-op group to be on OA post-operatively (p = 0.005); however, there were no differences in weight or symptom improvement. Sub-group analysis of the 53 patients on OA demonstrated significant improvement in clinical symptoms in the low-morphine cohort compared to the mid-morphine cohort (p = 0.02), and OA dosing post-operatively in the low-morphine cohort diminished significantly compared to mid- and high-morphine cohort (p = 0.032). There was no significant difference in weight.

CONCLUSION

OA dosing pre-operatively significantly affects clinical success of GES placement. Criteria for offering GES implantation may need to take OA dosing into consideration.

Diagnosis and treatment of narcotic bowel syndrome

With increased prescription of opioids has come increased recognition of adverse consequences, including narcotic bowel syndrome (NBS). Characterized by incompletely controlled abdominal pain despite continued or increasing doses of opioids, NBS is estimated to occur in 4.2-6.4% of patients chronically taking opioids. Patients with NBS have a high degree of comorbid psychiatric illness, catastrophizing and disability; comorbid substance abuse must also be considered among this population. NBS should be distinguished from opioid-induced bowel disorder, which results from the effects of opioids on gastrointestinal motility and secretion. By contrast, the mechanisms of NBS are probably centrally mediated and include glial cell activation, bimodal opioid modulation in the dorsal horn, descending facilitation of pain and the glutaminergic system. Few treatments have been rigorously studied. A trial of opioid detoxification resulted in complete detoxification for the vast majority of patients with reduction in pain symptoms; however, despite improvement in pain, approximately half of patients returned to opioid use within 3 months. Improved strategies are needed to identify patients who will respond to detoxification and remain off opioids. Comorbid psychiatric and substance abuse disorders are barriers to durable response after detoxification and should be actively sought out and treated accordingly. An effective patient-physician relationship is essential.

Mechanisms of visceral pain in health and functional gastrointestinal disorders

Background and aims Chronic visceral pain is common both in patients with identifiable organic disease and also in those without any structural, biochemical or immunological abnormality such as in the functional gastrointestinal disorders (FGIDs). We aim to provide a contemporaneous summary of pathways involved in visceral nociception and how a variety of mechanisms may influence an individual's experience of visceral pain. Methods In this narrative review, we have brought together evidence through a detailed search of Medline in addition to using our experience and exposure to recent research developments from ourselves and other research groups. Results FGIDs are a heterogeneous group of disorders whose aetiology largely remains an enigma. The germane hypothesis for the genesis and maintenance of chronic visceral pain in FGIDs is the concept of visceral hypersensitivity. A number of peripheral and central mechanisms have been proposed to account for this epiphenomenon. In the periphery, inflammatory mediators activate and sensitize nociceptive afferent nerves by reducing their transduction thresholds and by inducing the expression and recruitment of hitherto silent nociceptors culminating in an increase in pain sensitivity at the site of injury known as primary hyperalgesia. Centrally, secondary hyperalgesia, defined as an increase in pain sensitivity in anatomically distinct sites, occurs at the level of the spinal dorsal horn. Moreover, the stress responsive physiological systems, genetic and psychological factors may modulate the experience of visceral pain. We also address some novel aetiological concepts in FGIDs, namely the gastrointestinal microbiota, connective tissue abnormalities and the gastrointestinal neuromuscular disorders. Firstly, the gastrointestinal microbiota is a diverse and dynamic ecosystem, that safeguards the host from external pathogens, aids in the metabolism of polysaccharides and lipids, modulates intestinal motility, in addition to modulating visceral perception. Secondly, connective tissue disorders, which traditionally have been considered to be confined largely to the musculoskeletal system, have an increasing evidence base demonstrating the presence of visceral manifestations. Since the sensorimotor apparatus of the GI tract is embedded within connective tissue it should not be surprising that such disorder may result in visceral pain and abnormal gut motility. Thirdly, gastrointestinal neuromuscular diseases refer to a heterogeneous group of disorders in which symptoms arise from impaired GI motor activity often manifesting as abnormal transit with or without radiological evidence of transient or persistent dilation of the viscera. Although a number of these are readily recognizable, such as achalasia or Hirschsprung's disease, the cause in a number of patients is not. An international working group has recently addressed this "gap", providing a comprehensive morphologically based diagnostic criteria. Conclusions/implications Although marked advances have been made in understanding the mechanisms that contribute to the development and maintenance of visceral pain, many interventions have failed to produce tangible improvement in patient outcomes. In the last part of this review we highlight an emerging approach that has allowed the definition and delineation of temporally stable visceral pain clusters, which may improve participant homogeneity in future studies, potentially facilitate stratification of treatment in FGID and lead to improvements in diagnostic criteria and outcomes.

A review of the clinical manifestations, pathophysiology and management of opioid bowel dysfunction and narcotic bowel syndrome

Opioids are widely used for the treatment of malignant and non-malignant pains. These medications are accompanied by adverse effects, in particular gastrointestinal symptoms known as opioid bowel dysfunction (OBD). The most common symptom of OBD is refractory constipation that is usually stable regardless of the use of laxatives. Narcotic bowel syndrome (NBS) is a subset of OBD described as ambiguous chronic pain aggravated by continual or increased opioid use for pain relief. Pathophysiology of these disorders are not definitely disentangled. Some challenging hypothesis have been posed leading to specific management in order to mitigate the adverse effects. This article is a review of the literature on the prevalence, pathophysiology and management of OBD and NBS.