High doses of oxycodone–naloxone combination may provide poor analgesia

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.

The role of oxycodone/naloxone in the management of patients with pain and opioid-induced constipation

INTRODUCTION

Common opioid adverse effects (AE) of the gastrointestinal tract include opioid-induced constipation (OIC) and opioid-induced bowel dysfunction (OIBD) with traditional laxatives being of limited efficacy, having AEs and not addressing the pathophysiology of OIC or OIBD. Targeted treatment comprises of PAMORA (peripherally acting mu-opioid receptor antagonists) and a combination of an opioid receptor agonist with its antagonist, namely prolonged-release oxycodone with prolonged-release naloxone (OXN) tablets at a fixed ratio of 2:1. Oxycodone provides analgesia, whereas naloxone prevents binding or displaces it from opioid receptors located in the gut wall. Areas covered: The authors review the role of OXN in the management of patients with pain and OIC. A literature search was performed using the search terms 'oxycodone/naloxone' and 'opioid-induced constipation' using the PubMed database up to October 2018. Expert opinion: OXN delivers analgesia comparable (or superior versus placebo and in observational studies) to oxycodone alone and other opioids with a limited or decreased disturbing effect on bowel function. OXN in daily doses of up to 160 mg/80 mg provides effective analgesia with little negative impact on bowel function. OXN may be successfully used in patients with chronic pain, to prevent or treat symptoms of OIC and OIBD.

Treatment of failed back surgery syndrome in a forty-three-year-old man with high-dose oxycodone/naloxone

Introduction:

Failed back surgery syndrome (FBSS) is an increasing cause of chronic pain in most countries. This poses high costs to both patients and National Health Organizations.

Case Presentation:

In this report, multimodal pain management based on daily high-dose oxycodone/naloxone (OXN 180/90 mg) led to reduced patient's pain score and improved quality of life.

Conclusions:

Oxycodone/naloxone can be a good alternative for the management of FBSS when other interventional or pharmacologic strategies have failed. In this case report, higher doses than those recommended as a maximum daily ceiling (80/40 mg) were safely used in one selected patient with noncancer severe pain.

Emerging therapies for patients with symptoms of opioid-induced bowel dysfunction

Opioid-induced bowel dysfunction (OIBD) comprises gastrointestinal (GI) symptoms, including dry mouth, nausea, vomiting, gastric stasis, bloating, abdominal pain, and opioid-induced constipation, which significantly impair patients’ quality of life and may lead to undertreatment of pain. Traditional laxatives are often prescribed for OIBD symptoms, although they display limited efficacy and exert adverse effects. Other strategies include prokinetics and change of opioids or their administration route. However, these approaches do not address underlying causes of OIBD associated with opioid effects on mostly peripheral opioid receptors located in the GI tract. Targeted management of OIBD comprises purely peripherally acting opioid receptor antagonists and a combination of opioid receptor agonist and antagonist. Methylnaltrexone induces laxation in 50%–60% of patients with advanced diseases and OIBD who do not respond to traditional oral laxatives without inducing opioid withdrawal symptoms with similar response (45%–50%) after an oral administration of naloxegol. A combination of prolonged-release oxycodone with prolonged-release naloxone (OXN) in one tablet (a ratio of 2:1) provides analgesia with limited negative effect on the bowel function, as oxycodone displays high oral bioavailability and naloxone demonstrates local antagonist effect on opioid receptors in the GI tract and is totally inactivated in the liver. OXN in daily doses of up to 80 mg/40 mg provides equally effective analgesia with improved bowel function compared to oxycodone administered alone in patients with chronic non-malignant and cancer-related pain. OIBD is a common complication of long-term opioid therapy and may lead to quality of life deterioration and undertreatment of pain. Thus, a complex assessment and management that addresses underlying causes and patomechanisms of OIBD is recommended. Newer strategies comprise methylnaltrexone or OXN administration in the management of OIBD, and OXN may be also considered as a preventive measure of OIBD development in patients who require opioid administration.

Treatment with prolonged-release oxycodone/naloxone improves pain relief and opioid-induced constipation compared with prolonged-release oxycodone in patients with chronic severe pain and laxative-refractory constipation

PURPOSE

Laxative-refractory opioid-induced constipation (OIC) is defined as OIC despite using 2 laxatives with a different mechanism of action (based on the Anatomical Therapeutic Chemical Classification System level 4 term [contact laxatives, osmotically acting laxatives, softeners/emollients, enemas, and others]). OIC has a significant impact on the treatment and quality of life of patients with severe chronic pain. This noninterventional, observational, real-life study in Belgium investigated the efficacy of prolonged-release oxycodone/naloxone combination (PR OXN) treatment regarding pain relief and OIC compared with previous prolonged-release oxycodone (PR OXY) treatment for laxative-refractory OIC in daily clinical practice.

METHODS

Laxative-refractory OIC patients with severe chronic pain were treated with PR OXN for 12 weeks (3 visits). Pain relief (assessed on a numerical rating scale) and OIC (assessed by using the Bowel Function Index [BFI]) were evaluated at each visit. A responder was defined as a patient who had: (1) no worsening of pain at the last visit compared with visit 1 or a numerical rating scale ≤4 at visit 3/last visit; and (2) a reduction in BFI ≥12 units at visit 3/last visit compared with visit 1; or (3) a BFI ≤28.8 at visit 3/last visit.

FINDINGS

Sixty-eight laxative-refractory OIC patients with severe chronic pain (mean (sd) age 59.8 (13.3) years, 67.6% female and 91.2% non-malignant pain) were treated for 91 days with PR OXN (median daily dose, 20 mg). Treatment with PR OXN resulted in a significant and clinically relevant decrease of pain of 2.1 units (P < 0.001; 95% CI, 1.66-2.54) and of BFI by 48.5 units (P < 0.001; 95% CI, 44.4-52.7) compared with PR OXY treatment; use of laxatives was also significantly reduced (P < 0.001). Approximately 95% of patients were responders, and quality of life (as measured by using the EQ-5D) improved significantly. Adverse events were opioid related, and PR OXN treatment was well tolerated.

IMPLICATIONS

Treatment with PR OXN resulted in a significant and clinically relevant reduction in OIC compared with previous PR OXY treatment for these patients with severe chronic pain and laxative-refractory OIC. Treatment with PR OXN also resulted in a significant improvement in pain relief and quality of life. ClinicalTrials.gov identifier: NCT01710917.

Naloxegol , a new drug for the treatment of opioid-induced constipation

INTRODUCTION

With increasing chronic opioid use, opioid-induced constipation (OIC) is becoming a relevant clinical challenge. Presently, only few treatments have been demonstrated to be more effective than placebo in treating OIC but most of them have a restricted clinical application because of side effects. Naloxegol , an orally administered, peripherally acting, μ-opioid receptor antagonist (PAMORA), was developed for the treatment of OIC.

AREA COVERED

This review summarizes published information and presentations at meetings on the effects of naloxegol in OIC. Pharmacodynamic studies have demonstrated that naloxegol inhibits gastrointestinal opioid effects while preserving central analgesic actions. Phase II and Phase III studies in patients with non-cancer OIC have confirmed the efficacy of naloxegol to inhibit OIC, and the most consistent efficacy was seen with the 25 mg dose once daily. Adverse events were mainly gastrointestinal in origin and usually transient and mild. There were no signs of opioid withdrawal in the studies. Safety and tolerability were also shown in a long-term safety study. Regulatory authorities have recently approved the use of naloxegol in OIC.

EXPERT OPINION

Naloxegol is the first approved, orally available PAMORA. The drug has the potential to substantially improve management of OIC patients.

Naloxegol for the treatment of opioid-induced constipation

With increasing chronic opioid use, opioid-induced constipation (OIC) is a rapidly increasing clinical challenge. Naloxegol, an orally administered, peripherally-acting, µ-opioid receptor antagonist, was developed for the treatment of OIC. This drug profile summarizes published information and presentations at meetings on the effects of naloxegol in OIC. In animal studies, naloxegol was able to inhibit gastrointestinal opioid effects while preserving central analgesic actions and human pharmacodynamic studies were in agreement with such mode of action. Phase II and Phase III studies in patients with non-cancer OIC confirmed the efficacy of naloxegol to inhibit OIC, and the most consistent efficacy was seen with the 25 mg dose once daily. There were no signs of opioid withdrawal in these studies. Side effects were mainly gastrointestinal in origin, and usually transient and mild. A long-term safety study showed no new adverse events. The US FDA and EMA are currently evaluating the use of naloxegol in OIC.

Toward a systematic approach to opioid rotation

Patients requiring chronic opioid therapy may not respond to or tolerate the first opioid prescribed to them, necessitating rotation to another opioid. They may also require dose increases for a number of reasons, including worsening disease and increased pain. Dose escalation to restore analgesia using the primary opioid may lead to increased adverse events. In these patients, rotation to a different opioid at a lower-than-equivalent dose may be sufficient to maintain adequate tolerability and analgesia. In published trials and case series, opioid rotation is performed either using a predetermined substitute opioid with fixed conversion methods, or in a manner that appears to be no more systematic than trial and error. In clinical practice, opioid rotation must be performed with consideration of individual patient characteristics, comorbidities (eg, concurrent psychiatric, pulmonary, renal, or hepatic illness), and concurrent medications, using flexible dosing protocols that take into account incomplete opioid cross-tolerance. References cited in this review were identified via a search of PubMed covering all English language publications up to May 21, 2013 pertaining to opioid rotation, excluding narrative reviews, letters, and expert opinion. The search yielded a total of 129 articles, 92 of which were judged to provide relevant information and subsequently included in this review. Through a review of this literature and from the authors’ empiric experience, this review provides practical information on performing opioid rotation in clinical practice.

Oxycodone/Naloxone: role in chronic pain management, opioid-induced constipation, and abuse deterrence

The use of opioids in the treatment of chronic pain is widespread; the prevalence of specific opioids varies from country to country and depends on product availability, national formulary systems, and provider preferences. Patients often receive opioids for legitimate treatment of pain conditions, but on the opposite side of the spectrum, nonmedical use of opioids is a significant public health concern. Opioids are associated with several side effects, and constipation is the most commonly reported and persistent symptom. Unlike some adverse effects associated with opioid use, tolerance does not develop to constipation. Opioid-induced constipation (OIC) is the most prevalent patient complaint associated with opioid use and has been associated with declines in various quality of life measures. OIC can be extremely difficult for patients to tolerate and may prompt patients to decrease or discontinue opioid treatment. Current management strategies for OIC are often insufficient. A prolonged-release formulation of oxycodone/naloxone (OXN) has been investigated for the treatment of nonmalignant and cancer pain and mitigation of OIC, and evidence is largely favorable. Studies have demonstrated the capability of OXN to alleviate OIC while maintaining pain control comparable to oxycodone-only regimens. There is insufficient evidence for OXN efficacy for patients with mild OIC or patients maintained on high doses of opioids, and use in these populations is controversial. The reduction of costs associated with OIC may provide overall cost effectiveness with OXN. Additionally, the presence of naloxone may deter abuse/misuse by those seeking to misuse the formulation by modes of administration other than oral ingestion. Most studies to date have occurred in European countries, and phase 3 trials continue in the United States. This review will include current therapeutic options for pain and constipation, unique characteristics of OXN, evidence related to use of OXN and its place in therapy, discussion of opioid abuse/misuse, and various abuse-deterrent mechanisms, and areas of continuing research.

Update on tamper-resistant drug formulations

An expert panel convened in 2005 by the College on Problems of Drug Dependence (CPDD) to consider strategies to reduce the risk of prescription medication abuse concluded that drug formulation plays a significant role in determining risk of abuse. Efforts on the part of the pharmaceutical industry to develop drugs that deter abuse have focused primarily on opioid formulations resistant to common forms of tampering, most notably crushing or dissolving the tablet to accelerate release. Several opioid formulations developed to be tamper resistant have been approved, but the US Food and Drug Administration has not approved explicit label claims of abuse deterrence and has stated that any such claim will require substantial postmarketing data. Drug development efforts in this area raise questions about the relative impact of abuse-deterrent formulations, not only on individuals who might abuse a medication, but also on patients who are compliant with therapy. This review discusses progress since the 2005 CPDD meeting with an emphasis on opioids. Articles cited in the review were identified via a PubMed search covering the period between January 1, 2000, and October 5, 2011. Scientific work presented by the authors and their colleagues at meetings held through May 2012 also was included. Published literature suggests that development of abuse-deterrent products will require broad public health support and continued encouragement from regulatory authorities so that such products will become the expected standard of care for certain drug classes.

The place of oxycodone/naloxone in chronic pain management

Opioid analgesics are usually effective in the management of severe chronic pain. However, symptoms of opioid-induced bowel dysfunction (OIBD) are common during opioid therapy. Opioid-induced bowel dysfunction is often unsuccessfully managed due to limited effectiveness and numerous adverse effects of traditional laxatives. Newer treatment possibilities directed at the pathomechanism of OIBD comprise combined prolonged-release oxycodone with prolonged-release naloxone (oxycodone/naloxone) tablets. Oxycodone/naloxone provides effective analgesia with limited impact on bowel function as oxycodone displays high oral bioavailability and naloxone act as local antagonist on opioid receptors in the gastrointestinal tract due to nearly complete inactivation in the liver. Oxycodone/naloxone is administered to opioid-naive patients with severe pain and those unsuccessfully treated with weak opioids. Oxycodone/naloxone may be also administered to patients treated with strong opioids who experience intense symptoms of OIBD. Studies conducted to date indicate that oxycodone/naloxone is an important drug in chronic pain management, prevention and treatment of OIBD.

Oxycodone combined with opioid receptor antagonists: efficacy and safety

INTRODUCTION

A mu receptor antagonist combined with oxycodone (OXY) may improve pain control, reduce physical tolerance and withdrawal, minimizing opioid-related bowel dysfunction and act as an abuse deterrent.

AREAS COVERED

The authors cover the use of OXY plus ultra-low-dose naltrexone for analgesia and the use of sustained-release OXY plus sustained-release naloxone to reduce the opioid bowel syndrome. The authors briefly describe the use of sustained-release OXY and naltrexone pellets as a drug abuse deterrent formulation. Combinations of ultra-low-dose naltrexone plus OXY have been in separate trials involved in patients with chronic pain from osteoarthritis and idiopathic low back pain. High attrition and marginal differences between ultra-low-dose naltrexone plus OXY and OXY led to discontinuation of development. Prolonged-release (PR) naloxone combined with PR OXY demonstrates a consistent reduction in opioid-related bowel dysfunction in multiple randomized controlled trials. However, gastrointestinal side effects, including diarrhea, were increased in several trials with the combination compared with PR OXY alone. Analgesia appeared to be maintained although non-inferiority to PR OXY is not formally established. There were flaws to trial design and safety monitoring. Naltrexone has been combined with OXY in individual pellets encased in a capsule. This combination has been reported in a Phase II trial and is presently undergoing Phase III studies.

EXPERT OPINION

Due to the lack of efficacy the combination of altered low-dose naltrexone with oxycodone should cease in development. The combination of sustained release oxycodone plus naloxone reduces constipation with a consistent benefit. Safety has been suboptimally evaluated which is a concern. Although the drug is commercially available in several countries, ongoing safety monitoring particularly high doses would be important.

The impact of opioid analgesics on the gastrointestinal tract function and the current management possibilities

Opioid-induced bowel dysfunction (OIBD) comprises gastrointestinal symptoms such as constipation, anorexia, nausea, vomiting, gastro-oesophageal reflux, delayed digestion, abdominal pain, bloating, hard stool and incomplete evacuation that significantly deteriorate patients' quality of life and compliance. Approximately one third of patients treated with opioids do not adhere to the opioid regimen or simply quit the treatment due to OIBD. Several strategies are undertaken to prevent or treat OIBD. Traditional oral laxatives are used but their effectiveness is limited and they display adverse effects. Other possibilities comprise opioid switch or changing the administration route. New therapies target opioid receptors in the gut that seem to be the main source of OIBD. One is a combination of an opioid and opioid antagonist (oxycodone/naloxone) in prolonged-release tablets, and another is a purely peripherally acting opioid receptor antagonist (methylnaltrexone) available in subcutaneous injections. The aim of this article is to review the pathomechanism and possible treatment strategies of OIBD.

Use of oxycodone in pain management

Oxycodone is widely used to alleviate moderate-to severe acute pain, It is an effective analgesic for many types of pain, and is especially useful for paroxysmal spontaneous pain, steady pain, allodynia associated with postherpetic neuralgia, and it is also increasingly used in the management of cancer-related and chronic pain, oxycodone has been found to improve the quality of life of patients with many types of pain.

In 2011, following chemical and physical manipulation, an extended-release form of oxycodone was developed in order to maintain its rate-controlling mechanism. This new formulation significantly improved analgesia among patients with moderate-to-severe chronic osteoarthritis pain with an adverse event profile similar to that of other opioids. The long-term safety and efficacy of extended-release form of oxycodone in relieving moderate-to-severe chronic pain has been demonstrated. In this study we discussed about different aspects of this drug in managing of various types of pain.