Effects of Naloxegol on Gastrointestinal Transit and Colonic Fecal Volume in Healthy Participants Receiving Oxycodone

Recommendations for the management of opioid-induced constipation - how to improve usability in clinical practice

INTRODUCTION

Opioid-induced constipation remains undertreated despite effective and safe treatment options exists. Previous guidelines have only been partially effective in improving management, possibly due to their complexity, and studies suggest that a simple setup of concise and behaviorally-orientated steps improves usability.

AREAS COVERED

This article introduces the concept of opioid-induced constipation and provides an overview of existing guidelines in this field. We also propose simplified recommendations for managing opioid-induced constipation, derived from a synthesis of current guidelines and the principles of optimal guideline design theory.

EXPERT OPINION

Despite standard treatment with laxatives and fluid intake in patients with opioid-induced constipation, escalation of treatment is often needed where μ-opioid receptor antagonists or newer medications such as lubiprostone, linaclotide, or prucalopride are used. Previous guidelines have not been used sufficiently and thus management of the condition is often insufficient. We therefore propose simplified recommendations to management, which we believe can come into broader use. It was validated in primary care for credibility, clarity, relevance, usability, and overall benefit. We believe that this initiative can lead to better management of the substantial proportion of patients suffering from side effects of opioids.

Effects of opium tincture on the enteric and central nervous systems: A randomized controlled trial

Opioids change gut motility, and opium tincture has been used for treatment of chronic diarrhoea for centuries. However, the effects have never been documented in controlled trials. We aimed to investigate the effects of opium tincture on gastrointestinal transit and motility, frequency of bowel movements, stool consistency, gastrointestinal symptoms and sedation. Twenty healthy subjects were included in this randomized controlled trial. Opium tincture or placebo was each applied for 9 days. Gastrointestinal transit and motility were investigated with the 3D-transit system. Bowel movements and gastrointestinal symptoms were recorded daily. General cognition, reaction time, memory and electroencephalography were used to assess effects on the central nervous system. Opium tincture doubled colonic transit (49 vs. 23 h, p < 0.001), decreased antegrade colonic movements (p < 0.05), reduced daily bowel movements (0.7 vs. 1.2, p < 0.001) and increased stool consistency (Type 3 vs. Type 4, p < 0.001). No changes in general cognition, reaction time or memory were observed, and minor changes of power observed by electroencephalography did not indicate sedation. This study is the first to show that opium tincture has anti-propulsive properties in the healthy gut, while no sedative effects were seen. This indicates that opium tincture is a relevant and safe treatment option in chronic diarrhoea.

Importance of blinding and expectations in opioid-induced constipation: evidence from a randomized controlled trial

OBJECTIVES

Previous studies have found little association between objective measures and the subjective experience of opioid-induced constipation. The subjective experience of opioid-induced constipation may be influenced by treatment expectations. While most trials control for treatment expectations through blinding, success rate is generally low. This study aimed to explore the association between objective measures and the subjective experience of opioid-induced constipation, while considering blinding success and treatment expectations, and other psychological factors.

METHODS

Data from a randomized, double-blinded, placebo-controlled crossover trial including 21 healthy male participants was analyzed. Participants received either placebo, tapentadol, or oxycodone (in equipotent doses) for 14 days. They were assessed on objective and subjective measures of opioid-induced constipation (gastrointestinal transit time and the Patient Assessment of Constipation-Symptoms questionnaire, respectively), treatment guesses to indicate blinding success, and psychological factors.

RESULTS

There was a strong association between objective and subjective measures of opioid-induced constipation when participants were treated with oxycodone (r=0.676, p=0.006). Furthermore, participants were able to guess that they received active treatment when treated with oxycodone (p<0.001), suggesting that treatment expectations may have influenced the subjective experience of symptoms. Finally, patterns of moderate associations between opioid-induced constipation and other psychological factors emerged, although none reached significance (p>0.05).

CONCLUSIONS

Results indicate that treatment expectations could play an important role in the subjective experience of opioid-induced constipation, and support the importance of assessing blinding success in study trials. Besides expectations, other psychological factors may be associated with opioid-induced constipation.

Tapentadol results in less deterioration of gastrointestinal function and symptoms than standard opioid therapy in healthy male volunteers

BACKGROUND

Tapentadol is a combined opioid agonist and norepinephrine reuptake inhibitor with fewer gastrointestinal side effects at equianalgesic doses compared with classical strong opioids. Previous studies on tapentadol have included multi-morbid patients in whom confounders exclude detailed assessment of the mechanistic effects and strict comparison with other opioids or placebo. This study aimed at investigating the effects of tapentadol and oxycodone on gastrointestinal motility and gastrointestinal side effects.

METHODS

21 healthy males participated in a randomized, double-blind, placebo-controlled, crossover study. Tapentadol (50 mg twice daily), oxycodone (10 mg twice daily), or placebo tablets were administered for 14 days. Segmental gastrointestinal transit times and colonic motility parameters were measured with electromagnetic capsules. Gastrointestinal side effects were assessed using questionnaires.

KEY RESULTS

During dosing with tapentadol, gastrointestinal side effects and motility parameters were on placebo level. Compared with tapentadol, oxycodone increased whole gut transit time by 17.9 hours (p = .015) and rectosigmoid transit time by 6.5 hours (p = .005). Compared with tapentadol, oxycodone also reduced long, fast antegrade colonic movements (p = .001). In comparison with placebo, oxycodone prolonged whole gut transit time by 31.6 hours, (p < .001). Moreover, less long, fast antegrade colonic movements (p = .002) were observed during oxycodone. For oxycodone only, slow colonic movements were associated with gastrointestinal side effects.

CONCLUSIONS & INFERENCES

In this mechanistic study, tapentadol caused significantly less colonic dysmotility and gastrointestinal side effects as compared with oxycodone in equianalgesic doses.

Management of Opioid-Induced Constipation and Bowel Dysfunction: Expert Opinion of an Italian Multidisciplinary Panel

The prescribing and use of opioid analgesics is increasing in Italy owing to a profusion in the number and types of opioid analgesic products available, and the increasing prevalence of conditions associated with severe pain, the latter being related to population aging. Herein we provide the expert opinion of an Italian multidisciplinary panel on the management of opioid-induced constipation (OIC) and bowel dysfunction. OIC and opioid-induced bowel dysfunction are well-recognised unwanted effects of treatment with opioid analgesics that can profoundly affect quality of life. OIC can be due to additional factors such as reduced mobility, a low-fibre diet, comorbidities, and concomitant medications. Fixed-dose combinations of opioids with mu (μ) opioid receptor antagonists, such as oxycodone/naloxone, have become available, but have limited utility in clinical practice because the individual components cannot be independently titrated, creating a risk of breakthrough pain as the dose is increased. A comprehensive prevention and management strategy for OIC should include interventions that aim to improve fibre and fluid intake, increase mobility or exercise, and restore bowel function without compromising pain control. Recommended first-line pharmacological treatment of OIC is with an osmotic laxative (preferably polyethylene glycol [macrogol]), or a stimulant laxative such as an anthraquinone. A second laxative with a complementary mechanism of action should be added in the event of an inadequate response. Second-line treatment with a peripherally acting μ opioid receptor antagonist (PAMORA), such as methylnaltrexone, naloxegol or naldemedine, should be considered in patients with OIC that has not responded to combination laxative treatment. Prokinetics or intestinal secretagogues, such as lubiprostone, may be appropriate in the third-line setting, but their use in OIC is off-label in Italy, and should therefore be restricted to settings such as specialist centres and clinical trials.

Endogenous opiates and behavior: 2019

This paper is the forty-second consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2019 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides and receptors as well as effects of opioid/opiate agonists and antagonists. The review is subdivided into the following specific topics: molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (1), the roles of these opioid peptides and receptors in pain and analgesia in animals (2) and humans (3), opioid-sensitive and opioid-insensitive effects of nonopioid analgesics (4), opioid peptide and receptor involvement in tolerance and dependence (5), stress and social status (6), learning and memory (7), eating and drinking (8), drug abuse and alcohol (9), sexual activity and hormones, pregnancy, development and endocrinology (10), mental illness and mood (11), seizures and neurologic disorders (12), electrical-related activity and neurophysiology (13), general activity and locomotion (14), gastrointestinal, renal and hepatic functions (15), cardiovascular responses (16), respiration and thermoregulation (17), and immunological responses (18).

Although tapentadol and oxycodone both increase colonic volume, tapentadol treatment resulted in softer stools and less constipation: a mechanistic study in healthy volunteers

OBJECTIVES

Opioids are often used in treatment of severe pain, although many patients experience gastrointestinal side-effects like constipation. The aim of the current study was to investigate changes in colonic volume, as the result of both colonic motility and fluid transport, in healthy volunteers during opioid treatment with tapentadol as compared with oxycodone and placebo.

METHODS

In a randomized, double-blind, cross-over study, 21 healthy male volunteers were administered equianalgesic dosages of oral tapentadol (50 mg bid), oxycodone (10 mg bid) or corresponding placebo for 14 days. Segmental colonic volumes were quantified using T2-weighted magnetic resonance images, and gastrointestinal side-effects were assessed with questionnaires.

RESULTS

Total colonic volume increase during treatment was higher during tapentadol and oxycodone treatment (median 48 and 58 mL) compared to placebo (median -14 mL, both p≤0.003). Tapentadol (and placebo) treatment resulted in more bowel movements (both p<0.05) and softer stool consistency as compared with oxycodone (both p<0.01). Only oxycodone treatment was associated with increased constipation, straining during defecation, and tiredness (all p≤0.01). The colonic volume increase during treatment was directly associated with softer stools during tapentadol treatment (p=0.019).

CONCLUSIONS

Tapentadol treatment increased colonic volume without leading to harder stools, likely as the opioid sparing effects result in less water absorption from the gut lumen. Oxycodone treatment also increased colonic volume, but with a simultaneous increase in stool dryness and gastrointestinal and central nervous system side-effects. The results confirm that tapentadol treatment may be advantageous to oxycodone regarding tolerability to pain treatment.

Ambulatory assessment of colonic motility using the electromagnetic capsule tracking system: Effect of opioids

BACKGROUND

Opioid treatment often causes debilitating constipation. However, it is not well described how opioids affect colonic motility and whether opioid-induced constipation is due to either a decrease of powerful peristaltic contractions or "uncoordinated" peristalsis. The present study aims to investigate the effect of oxycodone on parameters of colonic motility and to determine whether motility is normalized by the opioid antagonist naloxegol.

METHODS

In two randomized, double-blind crossover trials, oxycodone or placebo was administered to 25 healthy males (Trial A), while another 24 healthy males were administered oxycodone with naloxegol or placebo (Trial B). Colonic motility was assessed by tracking the progression of an electromagnetic capsule throughout the large intestine. Segmental colonic transit times and capsule movements were calculated using displacement distance and velocity.

KEY RESULTS

In Trial A, colonic transit time increased during oxycodone treatment compared with placebo (39 vs 18 hours, P < .01). Displacement during long fast antegrade movements was shorter during oxycodone treatment than with placebo (10 vs 20 cm, P = .03). In Trial B, colonic transit time was faster during oxycodone + naloxegol than during oxycodone + placebo (40 vs 55 hours, P = .049), mainly caused by an increase of the percentwise fraction of distance covered by fast movements in the left colon (P = .001).

CONCLUSION & INFERENCES

Oxycodone treatment impaired colonic motility, manifested as increased transit time, specifically decreased long fast antegrade movements, and addition of naloxegol improved motility dynamics. In humans, the increased transit time during opioid treatment is caused by a decrease in long fast movements rather than uncoordinated peristalsis.