Fixed ratio (2:1) prolonged-release oxycodone/naloxone combination improves bowel function in patients with moderate-to-severe pain and opioid-induced constipation refractory to at least two classes of laxatives

Prolonged-Release (PR) Oxycodone/Naloxone Improves Bowel Function Compared with Oxycodone PR and Provides Effective Analgesia in Chinese Patients with Non-malignant Pain: A Randomized, Double-Blind Trial

Introduction

Prolonged-release oxycodone/naloxone (OXN PR), combining an opioid analgesic with selective blockade of enteric µ-opioid receptors, provided effective analgesia and improved bowel function in patients with moderate-to-severe pain and opioid-induced constipation in clinical trials predominantly conducted in Western countries. This double-blind randomized controlled trial investigated OXN PR (N = 116) versus prolonged-release oxycodone (OXY PR, N = 115) for 8 weeks at doses up to 50 mg/day in patients with moderate-to-severe, chronic, non-malignant musculoskeletal pain and opioid-induced constipation recruited in China.

Methods

A total of 234 patients at least 18 years of age with non-malignant musculoskeletal pain for more than 4 weeks that was moderate-to-severe in intensity and required round-the-clock opioid therapy were randomized (1:1) to OXN PR or OXY PR. The primary endpoint was bowel function using the Bowel Function Index (BFI). Secondary endpoints included safety, Brief Pain Inventory-Short Form (BPI-SF), use of analgesic and laxative rescue medication, and health-related quality of life (EQ-5D).

Results

While BFI scores were comparable at baseline, at week 8 improvements were greater with OXN PR vs OXY PR (least squares mean [LSM] difference (95% CI) − 9.1 (− 14.0, − 4.2); P < 0.001. From weeks 2 to 8, mean BFI scores were in the range of normal bowel function (≤ 28.8) with OXN PR but were in the range of constipation (> 28.8) at all timepoints with OXY PR. Analgesia with OXN PR was similar and non-inferior to OXY PR on the basis of modified BPI-SF average 24-h pain scores at week 8: LSM difference (95% CI) − 0.3 (− 0.5, − 0.1); P < 0.001. The most frequent treatment-related AEs were nausea (OXN PR 5% vs OXY PR 6%) and dizziness (4% vs 4%).

Conclusion

OXN PR provided clinically meaningful improvements in bowel function and effective analgesia in Chinese patients with moderate-to-severe musculoskeletal pain and pre-existing opioid-induced constipation.

Trial Registration

ClinicalTrials.gov, identifier NCT01918098.

Electronic supplementary material

The online version of this article (10.1007/s12325-020-01244-x) contains supplementary material, which is available to authorized users.

Pharmacovigilance in Hospice/Palliative Care: De-Prescribing Combination Controlled Release Oxycodone-Naloxone

Background: Pharmacovigilance studies in hospice/palliative care provide extra information to improve medication safety. Combination controlled release oxycodone-naloxone offers an alternative opioid with less risk of opioid-induced constipation. Objective: To examine why palliative care clinicians chose to cease oxycodone-naloxone and to explore immediate and short-term benefits and harms of this medication change. Design: A consecutive cohort study. Setting: 112 adults from 13 palliative care centers. Measurements: Reasons for ceasing medication and the harms and benefits that followed this 24 and 72 hours later. Symptom burdens were summarised by the National Cancer Institute Common Terminology Criteria for Adverse Events Toxicity Gradings. Results: Combination medication was most commonly ceased because of poor pain control or impaired hepatic function. The last median oral morphine equivalent oxycodone dose before the switch was 45 mg (range 7.5-240 mg) with 76 switched to an alternative long-acting opioid (initial median oral morphine equivalent dose being 45 mg [range 5-210 mg]). Subgroup analysis of those switched because of clinicians' concerns about hepatic dysfunction demonstrated this group were receiving significantly lower opioid doses pre-cessation compared to those switched because of other reasons( p = 0.007). Regardless of why the medication was changed, improvements in pain and constipation scores were seen, the latter associated with an attendant increase in laxatives. Conclusions: This preliminary work suggests that despite theoretical concerns regarding the effect of the naloxone on opioid doses, most people were switched safely to very similar opioid doses with attendant improvements in pain control.

Opioid-induced constipation: a narrative review of therapeutic options in clinical management

Pain therapy often entails gastrointestinal adverse events. While opioids are effective drugs for pain relief, the incidence of opioid-induced constipation (OIC) varies greatly from 15% to as high as 81%. This can lead to a significant impairment in quality of life, often resulting in discontinuation of opioid therapy. In this regard, a good doctor-patient relationship is especially pivotal when initiating opioid therapy. In addition to a detailed history of bowel habits, patient education regarding the possible gastrointestinal side effects of the drugs is crucial. In addition, the bowel function must be regularly evaluated for the entire duration of treatment with opioids. Furthermore, if the patient has preexisting constipation that is well under control, continuation of that treatment is important. In the absence of such history, general recommendations should include sufficient fluid intake, physical activity, and regular intake of dietary fiber. In patients of OIC with ongoing opioid therapy, the necessity of opioid use should be critically reevaluated in terms of an with acceptable quality of life, particularly in cases of non-cancer pain. If opioids must be continued, lowering the dose may help, as well as changing the type of opioid. If these measures do not suffice, the next step for persistent OIC is the administration of laxatives. If these are ineffective as well, treatment with peripherally active μ-opioid receptor antagonists should be considered. Enemas and irrigation are emergency measures, often used as a last resort.

A comparison between the administration of oral prolonged-release oxycodone-naloxone and transdermal fentanyl in patients with moderate-to-severe cancer pain: a propensity score analysis

BACKGROUND

Opioids are the most important pharmacological treatment for moderate-to-severe cancer pain, but side effects limit their use. Transdermal fentanyl (TDF) and oral prolonged-release oxycodone-naloxone (OXN-PR) are effective in controlling chronic pain, with less constipation compared to other opioids. However, TDF and OXN-PR have never been directly compared.

PATIENTS AND METHODS

Cancer patients with moderate-to-severe chronic pain were consecutively enrolled in two prospective 28-day trials, received either TDF or OXN-PR, and were assessed at baseline and after 7, 14, 21, and 28 days. The primary endpoint was 28-day analgesic response rate (average pain intensity decrease ≥30% from baseline). Other outcome measures included opioid daily dose changes over time; need for adjuvant analgesics; number of switches; premature discontinuation; presence and severity of constipation; and other adverse drug reactions. To compare the efficacy and the safety of TDF and OXN-PR, we used the propensity score analysis to adjust for heterogeneity between the two patient groups.

RESULTS

Three hundred ten out of 336 patients originally treated (119 TDF and 191 OXN-PR) were included in the comparative analysis. The amount of responders was comparable after TDF (75.3%) and OXN-PR administration (82.9%, not significant [NS]). The final opioid daily dose expressed as morphine equivalent was 113.6 mg for TDF and 44.5 mg for OXN-PR (p<0.0001). A daily opioid dose escalation >5% was less common after OXN-PR (19.3%) than after TDS administration (37.9%, p<0.0001). Opioid switches and discontinuation were similar in both groups. Severe constipation in the two groups was comparable (32.6% after TDF vs 24.7% after OXN-PR, NS). Nausea, vomiting, and dry mouth were significantly less frequent in the OXN-PR group than in the TDF group.

CONCLUSION

Despite a similar analgesic activity in moderate-to-severe cancer pain, OXN-PR is characterized by lower daily dosages, less need for drug escalation, and fewer side effects compared to TDF.

Opioids in Gastroenterology: Treating Adverse Effects and Creating Therapeutic Benefits

The use of opioid medications on both an acute and chronic basis is ubiquitous in the United States. As opioid receptors densely populate the gastrointestinal tract, symptoms and side effects can be expected in these patients. In the esophagus, dysmotility may result, manifesting with dysphagia and a syndrome indistinguishable from primary achalasia. In the stomach, a marked delay in gastric emptying may occur with postprandial nausea and early satiety. Postoperatively, particularly with abdominal surgery, opioid-induced ileus may ensue. In the colon, opioid-induced constipation is common. A unique syndrome termed narcotic bowel syndrome is characterized by chronic abdominal pain often accompanied by nausea and vomiting in the absence of other identifiable causes. With the recognition of the important role of opioids on gastrointestinal function, novel drugs have been developed that use this physiology. These medications include peripheral acting opioid agonists to treat opioid-induced constipation and combination agonist and antagonists used for diarrhea-predominant irritable bowel syndrome. This review summarizes the most recent data in these areas.

Peripherally acting μ-opioid receptor antagonists as treatment options for constipation in noncancer pain patients on chronic opioid therapy

Opioid-induced constipation (OIC), a prevalent and distressing side effect of opioid therapy, does not reliably respond to treatment with conventional laxatives. OIC can be a treatment-limiting adverse event. Recent advances in medications with peripherally acting μ-opioid receptor antagonists, such as methylnaltrexone, naloxegol, and alvimopan, hold promise for treating OIC and thus extending the benefits of opioid analgesia to more chronic pain patients. Peripherally acting μ-opioid receptor antagonists have been clinically tested to improve bowel symptoms without compromise to pain relief, although there are associated side effects, including abdominal pain. Other treatment options include fixed-dose combination products of oxycodone analgesic together with naloxone.

The effect of naloxone treatment on opioid-induced side effects: A meta-analysis of randomized and controlled trails

BACKGROUND

To evaluate the effects of naloxone on opioid-induced side effects, the present meta-analysis was constructed.

METHODS

Electronic databases including PubMed, EMBASE, and CNKI (China National Knowledge Internet) were used for literature search. Studies on comparison of opioid-side effects between naloxone-treated group and placebo or normal saline-related group were included in the meta-analysis. Heterogeneity analysis was performed with Chi-square and I test. Pooled analysis was based on fixed-effects model, if heterogeneity between the eligible studies was negligible (I < 50%, P > 0.05), otherwise, random-effects model was used. Sensitivity analysis was applied to assess the robustness of the results and publication bias was evaluated by Begg and Egger test.

RESULTS

Thirteen studies including 1138 patients were included in the meta-analysis. Pooled analysis indicated that naloxone could significantly reduce the occurrence of pruritus (RR [risk ratio] = 0.252, 95% CI [confidence interval] = 0.137-0.464), nausea (RR = 0.323, 95% CI = 0.245-0.428), and vomiting (RR = 0.338, 95% CI = 0.192-0.593) which were induced by opioids. However, naloxone did not relieve pain (standardized mean difference [SMD] = -0.052, 95% CI = -0.453 to 0.348) and somnolence (RR = 0.561, 95% CI = 0.287 to 1.097) in patients received opioid treatment. Additionally, there were no significant publication bias between the included studies (Begg test, P = 0.602; Egger test, P = 0.388).

CONCLUSION

Addition of naloxone might act as an effective treatment for prophylaxis of opioid-induced pruritus, nausea, and vomiting in clinical practice.

Expression and physiology of opioid receptors in the gastrointestinal tract

PURPOSE OF REVIEW

Stimulation of opioid receptors elicits analgesic effect not only in the central nervous system, but also in the gastrointestinal tract, where a high concentration of opioid receptors can be found within the enteric nervous system as well as muscular and immune cells. Along with antinociception, opioid receptors in the stomach and intestine relay signals crucial for secretory and motor gastrointestinal function.

RECENT FINDINGS

The review focuses on the utility of opioid receptor antagonists, which is generally contributing to the management of postoperative ileus and opioid bowel dysfunction in chronic pain patients nonetheless, opioid receptor antagonists can also be useful in the treatment of irritable bowel syndrome and chronic idiopathic constipation. The study also discusses several antidiarrheal opioid agonists, as well as opioids and opioid mimetics encompassing the concept of ligand-biased agonism and truncated opioid receptor splice variants.

SUMMARY

Good understanding of the localization and the role of opioid receptors is vital for regulation of various pathophysiological processes in the gastrointestinal tract and may simultaneously provide a tempting approach in eliminating adverse effects related to centrally acting opioids.

Opioid-induced constipation: advances and clinical guidance

Currently opioids are the most frequently used medications for chronic noncancer pain. Opioid-induced constipation is the most common adverse effect associated with prolonged use of opioids, having a major impact on quality of life. There is an increasing need to treat opioid-induced constipation. With the recent approval of medications for the treatment of opioid-induced constipation, there are several therapeutic approaches. This review addresses the clinical presentation and diagnosis of opioid-induced constipation, barriers to its diagnosis, effects of opioids in the gastrointestinal tract, differential tolerance to opiates in different gastrointestinal organs, medications approved and in development for the treatment of opioid-induced constipation, and a proposed clinical management algorithm for treating opioid-induced constipation in patients with noncancer pain.

Endogenous opiates and behavior: 2014

This paper is the thirty-seventh consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2014 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (endogenous opioids and receptors), and the roles of these opioid peptides and receptors in pain and analgesia (pain and analgesia); stress and social status (human studies); tolerance and dependence (opioid mediation of other analgesic responses); learning and memory (stress and social status); eating and drinking (stress-induced analgesia); alcohol and drugs of abuse (emotional responses in opioid-mediated behaviors); sexual activity and hormones, pregnancy, development and endocrinology (opioid involvement in stress response regulation); mental illness and mood (tolerance and dependence); seizures and neurologic disorders (learning and memory); electrical-related activity and neurophysiology (opiates and conditioned place preferences (CPP)); general activity and locomotion (eating and drinking); gastrointestinal, renal and hepatic functions (alcohol and drugs of abuse); cardiovascular responses (opiates and ethanol); respiration and thermoregulation (opiates and THC); and immunological responses (opiates and stimulants). This paper is the thirty-seventh consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2014 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (endogenous opioids and receptors), and the roles of these opioid peptides and receptors in pain and analgesia (pain and analgesia); stress and social status (human studies); tolerance and dependence (opioid mediation of other analgesic responses); learning and memory (stress and social status); eating and drinking (stress-induced analgesia); alcohol and drugs of abuse (emotional responses in opioid-mediated behaviors); sexual activity and hormones, pregnancy, development and endocrinology (opioid involvement in stress response regulation); mental illness and mood (tolerance and dependence); seizures and neurologic disorders (learning and memory); electrical-related activity and neurophysiology (opiates and conditioned place preferences (CPP)); general activity and locomotion (eating and drinking); gastrointestinal, renal and hepatic functions (alcohol and drugs of abuse); cardiovascular responses (opiates and ethanol); respiration and thermoregulation (opiates and THC); and immunological responses (opiates and stimulants).

Efficacy and tolerability of oral oxycodone and oxycodone/naloxone combination in opioid-naïve cancer patients: a propensity analysis

Background

World Health Organization step III opioids are required to relieve moderate-to-severe cancer pain; constipation is one of the most frequent opioid-induced side effects. A fixed combination, prolonged-release oxycodone/naloxone (OXN), was developed with the aim of reducing opioid-related gastrointestinal side effects. The objective of this study was to compare the efficacy and safety of prolonged-release oxycodone (OXY) alone to OXN in opioid-naïve cancer patients with moderate-to-severe pain.

Methods

Propensity analysis was utilized in this observational study, which evaluated the efficacy, safety, and quality of life.

Results

Out of the 210 patients recruited, 146 were matched using propensity scores and included in the comparative analysis. In both groups, pain intensity decreased by ≈3 points after 60 days, indicating comparable analgesic efficacy. Responder rates were similar between groups. Analgesia was achieved and maintained with similarly low and stable dosages over time (12.0–20.4 mg/d for OXY and 11.5–22.0 mg/d for OXN). Bowel Function Index (BFI) and laxative use per week improved from baseline at 30 days and 60 days in OXN recipients (−16, P<0.0001 and −3.5, P=0.02, respectively); BFI worsened in the OXY group. The overall incidence of drug-related adverse events was 28.9% in the OXY group and 8.2% in the OXN group (P<0.01); nausea and vomiting were two to five times less frequent with OXN. Quality of life improved to a significantly greater extent in patients receiving OXN compared to OXY (increase in Short Form-36 physical component score of 7.1 points vs 3.2 points, respectively; P<0.001).

Conclusion

In patients with chronic cancer pain, OXN provided analgesic effectiveness that is similar to OXY, with early and sustained benefits in tolerability. The relationship between responsiveness to OXN and clinical characteristics is currently being investigated.

Prolonged-release oxycodone-naloxone for treatment of severe pain in patients with Parkinson's disease (PANDA): a double-blind, randomised, placebo-controlled trial

BACKGROUND

Pain is a common non-motor symptom of Parkinson's disease. We investigated the analgesic efficacy of prolonged-release oxycodone-naloxone (OXN PR) in patients with Parkinson's disease and chronic, severe pain.

METHODS

We did this phase 2 study in 47 secondary care centres in the Czech Republic, Germany, Hungary, Poland, Romania, Spain, and the UK. We enrolled patients with Hoehn and Yahr Stage II-IV Parkinson's disease, at least one type of severe pain, and an average 24-h pain score of at least 6 (assessed on an 11-point rating scale from 0=no pain to 10=pain as bad as you can imagine). Participants were randomly assigned (1:1) with a validated automated system (block size four) to either oral OXN PR or placebo for 16 weeks (starting dose oxycodone 5 mg, naloxone 2·5 mg, twice daily). Patients and investigators were masked to treatment assignment. The primary endpoint was average 24-h pain score at 16 weeks in the full analysis population. This study is registered with EudraCT (2011-002901-31) and ClinicalTrials.gov (NCT01439100).

FINDINGS

We enrolled 202 patients; 93 were assigned to OXN PR and 109 to placebo; the full analysis population consisted of 88 patients versus 106 patients. Least squares mean average 24-h pain score at 16 weeks in the full analysis population was 5·0 (95% CI 4·5 to 5·5) in the OXN PR group versus 5·6 (5·1 to 6·0) in the placebo group (difference -0·6, 95% CI -1·3 to 0·0; p=0·058). Similar proportions of patients in each group had adverse events (60/92 [65%] vs 76/109 [70%]), treatment-related adverse events (52/92 [57%] vs 62/109 [57%]), and serious adverse events (5/92 [5%] vs 7/109 [6%]). Treatment-related nausea was more common in the OXN PR group than in the placebo group (16/92 [17%] vs 10/109 [9%]), as was treatment-related constipation (16/92 [17%] vs 6/109 [6%]).

INTERPRETATION

The primary endpoint, based on the full analysis population at week 16, was not significant. Nonetheless, the results of this study highlight the potential efficacy of OXN PR for patients with Parkinson's disease-related pain and might warrant further research on OXN PR in this setting.

FUNDING

Mundipharma Research.

Chronic opioid induced constipation in patients with nonmalignant pain: challenges and opportunities

With the recent introduction and approval of medications directed at the treatment of opioid induced constipation (OIC) in patients with nonmalignant pain, there is increased interest and understanding of the unmet need and opportunities to enhance patient management. The high incidence of OIC is associated with rapid increase of narcotic analgesic prescriptions for nonmalignant chronic pain. This review addresses briefly the mechanisms of action of opioids that lead to OIC, the differential tolerance of gastrointestinal organs to the effects of opioids, the size and scope of the problem, the definition and outcome measures for OIC, current differential diagnosis and management algorithms, and the pharmacology and efficacy of treatments for OIC in patients with nonmalignant pain.

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.