Oxycodone/Naloxone Prolonged-Release: A Review of Its Use in the Management of Chronic Pain While Counteracting Opioid-Induced Constipation

Managing Severe Cancer Pain with Oxycodone/Naloxone Treatment: A Literature Review Update

Severe cancer pain substantially affects patients' quality of life, increasing the burden of the disease and reducing the disability-adjusted life years. Although opioid analgesics are effective, they may induce opioid-induced bowel dysfunction (OIBD). Oxycodone/naloxone combination therapy has emerged as a promising approach to mitigate opioid-induced constipation (OIC) while providing effective pain relief. This review provides an updated analysis of the literature of the last decade regarding the use of oxycodone/naloxone in the management of severe cancer pain. Through a comprehensive search of databases, studies focusing on the efficacy, safety, and patient experience of oxycodone/naloxone's prolonged release in severe cancer pain management were identified. Furthermore, the literature discusses the mechanism of action of naloxone in mitigating OIC without compromising opioid analgesia. Overall, the evidence suggests that oxycodone/naloxone combination therapy offers a valuable option for effectively managing severe cancer pain while minimizing opioid-induced constipation, thereby improving patients' quality of life. However, further research is needed to optimize dosing regimens, evaluate long-term safety, and assess patient outcomes in diverse cancer populations.

No pain, no strain: Targin® mitigates pain and constipation following spinal cord injury

BACKGROUND

Opioids effectively reduce chronic pain, but present significant side effects including opioid-induced constipation. Oxycodone/naloxone decreases pain and constipation in cancer patients, however its effect on spinal cord injury population remains understudied.

METHODS

We assessed whether oxycodone/naloxone reduces pain, constipation, and severity of autonomic dysreflexia in an individual with spinal cord injury. A 55-year-old male with C5 lesion presented with chief complaint of chronic pain received 5/2.5 mg and 20/10 mg oxycodone/naloxone for 6 and 2 weeks, respectively.

RESULTS

Oxycodone/naloxone improved pain, bowel function, and autonomic dysreflexia severity.

INTERPRETATION

Oxycodone/naloxone was effective in managing chronic pain and constipation in the studied case.

Oxycodone-Naloxone Combination Hinders Opioid Consumption in Osteoarthritic Chronic Low Back Pain: A Retrospective Study with Two Years of Follow-Up

Chronic low back pain (CLBP) due to osteoarthritis represents a therapeutic challenge worldwide. Opioids are extensively used to treat such pain, but the development of tolerance, i.e., less susceptibility to the effects of the opioid, which can result in a need for higher doses to achieve the same analgesic effect, may limit their use. Animal models suggest that ultra-low doses of opioid antagonists combined with opioid agonists can decrease or block the development of opioid tolerance. In this retrospective study, we tested this hypothesis in humans. In 2019, 53 patients suffering from CLBP were treated with either Oxycodone and Naloxone Prolonged Release (27 patients, OXN patients) or Oxycodone Controlled Release (26 patients, OXY patients). The follow-up period lasted 2 years, during which 10 patients discontinued the treatment, 5 out of each group. The remaining 43 patients reached and maintained the targeted pain relief, but at 18 and 24 months, the OXY patients showed a significantly higher oxycodone consumption than OXN patients to reach the same level of pain relief. No cases of respiratory depression or opioid abuse were reported. There were no significant differences in the incidence of adverse effects between the two treatments, except for constipation, more common in OXY patients. From our results, we can affirm that a long-term opioid treatment with oxycodone-naloxone combination, when compared with oxycodone only, may significantly hinder the development of opioid tolerance. We were also able to confirm, in our cohort, the well known positive effect of naloxone in terms of opioid-induced bowel dysfunction incidence reduction.

Safe use of opioids

Background: Opioids are effective analgesics for cancer pain and refractory non-cancer pain. Although they are essential medication, problematic issues on aberrant behavior and adverse events have rapidly emerged as social problems in Korea. This study aimed to describe the mechanisms, efficacy, and adverse events, especially how to deal with opioid dependency.Current Concepts: Opioid-induced aberrant behavior includes physical and psychological dependences (addiction), abuse, and diversion (giving prescribed opioids to another person). Most physicians are unfamiliar with how to handle patients presenting these problematic issues. Physical and psychological dependences develop through different pathophysiologic mechanisms, i.e., noradrenergic and dopaminergic pathways, respectively. Motivational enhancement therapy, psychosocial support, substitution therapy with buprenorphine, and adjunctive medications, including alpha-2 adrenergic agonist, antidepressants, and non-steroidal antiinflammatory drugs, are the mainstay of treatment for opioid dependency. Constipation, nausea/vomiting, drowsiness/sedation, delirium, itching sensation, voiding difficulty, dry mouth, opioid-induced hyperalgesia, and respiratory depression are well-known physical side effects of opioid consumption.Discussion and Conclusion: Research on the development history, epidemiology of opioid dependency, and its treatment are warranted to avoid an opioid crisis in Korea. Above all, thorough knowledge for physicians and patients is urgently needed.

Opioid Analgesia and Opioid-Induced Adverse Effects: A Review

Opioids are widely used as therapeutic agents against moderate to severe acute and chronic pain. Still, these classes of analgesic drugs have many potential limitations as they induce analgesic tolerance, addiction and numerous behavioural adverse effects that often result in patient non-compliance. As opium and opioids have been traditionally used as painkillers, the exact mechanisms of their adverse reactions over repeated use are multifactorial and not fully understood. Older adults suffer from cancer and non-cancer chronic pain more than younger adults, due to the physiological changes related to ageing and their reduced metabolic capabilities and thus show an increased number of adverse reactions to opioid drugs. All clinically used opioids are μ-opioid receptor agonists, and the major adverse effects are directly or potentially connected to this receptor. Multifunctional opioid ligands or peripherally restricted opioids may elicit fewer adverse effects, as shown in preclinical studies, but these results need reproducibility from further extensive clinical trials. The current review aims to overview various mechanisms involved in the adverse effects induced by opioids, to provide a better understanding of the underlying pathophysiology and, ultimately, to help develop an effective therapeutic strategy to better manage pain.

Structural Insights Accelerate the Discovery of Opioid Alternatives

Opioids such as morphine and oxycodone are analgesics frequently prescribed for the treatment of moderate or severe pain. Unfortunately, these medications are associated with exceptionally high abuse potentials and often cause fatal side effects, mainly through the μ-opioid receptor (MOR). Efforts to discover novel, safer, and more efficacious analgesics targeting MOR have encountered challenges. In this review, we summarize alternative strategies and targets that could be used to develop safer nonopioid analgesics. A molecular understanding of G protein-coupled receptor activation and signaling has illuminated not only the complexities of receptor pharmacology but also the potential for pathway-selective agonists and allosteric modulators as safer medications. The availability of structures of pain-related receptors, in combination with high-throughput computational tools, has accelerated the discovery of multitarget ligands with promising pharmacological profiles. Emerging clinical evidence also supports the notion that drugs targeting peripheral opioid receptors have potential as improved analgesic agents.

Acute Pain Management of Chronic Pain Patients in Ambulatory Surgery Centers

PURPOSE OF REVIEW

With the widespread growth of ambulatory surgery centers (ASCs), the number and diversity of operations performed in the outpatient setting continue to increase. In parallel, there is an increase in the proportion of patients with a history of chronic opioid use and misuse undergoing elective surgery. Patients with such opioid tolerance present a unique challenge in the ambulatory setting, given their increased requirement for postoperative opioids. Guidelines for managing perioperative pain, anticipating postoperative opioid requirements and a discharge plan to wean off of opioids, are therefore needed.

RECENT FINDINGS

Expert guidelines suggest using multimodal analgesia including non-opioid analgesics and regional/neuraxial anesthesia whenever possible. However, there exists variability in care, resulting in challenges in perioperative pain management. In a recent study of same-day admission patients, anesthesiologists correctly identified most opioid-tolerant patients, but used non-opioid analgesics only half the time. The concept of a focused ambulatory pain specialist on site at each ASC has been suggested, who in addition to providing safe anesthesia, could intervene early once problematic pain issues are recognized. This review focuses on perioperative pain management in three subsets of patients who exhibit opioid tolerance: those on large doses of opioids (including abuse-deterrent formulations) for chronic non-malignant or malignant pain; those who have ongoing opioid misuse; and those who were prior addicts and are now on methadone/suboxone maintenance. We also discuss perioperative pain management for patients who have implanted devices such as spinal cord stimulators and intrathecal pain pumps.

Pathophysiology and management of opioid-induced constipation: European expert consensus statement

Background

Opioid-induced bowel dysfunction is a complication of opioid therapy, in which constipation is the most common and problematic symptom. However, it is frequently under-recognised and thus effective management is often not instituted despite a number of treatment options.

Objective

The central objective of this study is to provide a summary of the pathophysiology and clinical evaluation of opioid-induced constipation and to provide a pragmatic management algorithm for day-to-day clinical practice.

Methods

This summary and the treatment algorithm is based on the opinion of a European expert panel evaluating current evidence in the literature.

Results

The pathophysiology of opioid-induced constipation is multi-faceted. The key aspect of managing opioid-induced constipation is early recognition. Specific management includes increasing fluid intake, exercise and standard laxatives as well as addressing exacerbating factors. The Bowel Function Index is a useful way of objectively evaluating severity of opioid-induced constipation and monitoring response. Second-line treatments can be considered in those with recalcitrant symptoms, which include gut-restricted or peripherally acting mu-opioid receptor antagonists. However, a combination of interventions may be needed.

Conclusion

Opioid-induced constipation is a common, yet under-recognised and undertreated, complication of opioid therapy. We provide a pragmatic step-wise approach to opioid-induced constipation, which should simplify management for clinicians.

Increases in controlled-release oxycodone utilisation following the subsidy of oxycodone with naloxone formulations: An Australian population-based study

PURPOSE

Despite increasing use of oxycodone/naloxone controlled-release (CR) in Australia, little is known about how it has affected the overall oxycodone CR market since its subsidy in 2011.

METHODS

We used Pharmaceutical Benefits Scheme dispensing claims (2006-2016) and interrupted time series analysis to examine changes in the quarterly rates of dispensing of oral oxycodone CR formulations (oxycodone/naloxone CR and single-ingredient oxycodone CR) and new oxycodone CR treatment episodes. We also performed a retrospective cohort study in a sample of people initiating a new oxycodone CR treatment episode in 2009, 2012/2013, and 2016 to compare opioid utilisation patterns over time.

RESULTS

The subsidy of oxycodone/naloxone CR was associated with a 1.6-fold increase in the growth rate of oxycodone CR dispensing, resulting from rapid uptake of low strength (≤5 mg) oxycodone/naloxone CR. In our cohort of initiators, the number of new oxycodone CR treatment episodes increased 2.1-fold between 2009 and 2016; in 2016, 91.4% of new treatment episodes involved oxycodone/naloxone CR. Comparing 2016 with 2009, we observed an increase in people initiating with a tablet strength less than or equal to 5-mg (risk difference [RD] = 21.1%, 95% CI, 19.9%-22.4%) in people initiating with no other opioid dispensing 90 days prior to initiation (RD = 5.2%, 3.8%-6.6%) and with no further opioid dispensing 90 days after initiation (RD = 8.8%, 7.4%-10.2%).

CONCLUSIONS

After its subsidy, the uptake of low-dose oxycodone/naloxone CR was greater than expected if it were substituting the single-ingredient oxycodone CR, resulting in an expansion of the oxycodone CR market.

New developments in the treatment of opioid-induced gastrointestinal symptoms

Chronic pain affects a large part of the global population, leading to an increase of opioid use. Opioid-induced constipation (OIC), a highly prevalent adverse effect of opioid use, has a major impact on patients' quality of life. Thanks to the introduction of new drugs for chronic constipation, which can also be used in OIC, and the development of peripherally acting mu-opioid receptor blockers, specifically for use in OIC, therapeutic options have seen major development. This review summarises current and emerging treatment options for OIC based on an extensive bibliographical search. Efficacy data for laxatives, lubiprostone, prucalopride, linaclotide, oxycodone/naloxone combinations, methylnaltrexone, alvimopan, naloxegol, naldemedine, axelopran, and bevenopran in OIC are summarised.

[Oxycodone, piritramide and tramadol for the management of postoperative pain : A registry study on use and effectiveness in clinical routine]

BACKGROUND

In the context of improving perioperative pain management and shortening hospital stays, potent oral analgesics, such as slow release opioids, are gaining increasingly in importance.

OBJECTIVE

The aim of this study was to compare the use and effectiveness of different opioids in postoperative pain treatment in Germany.

MATERIALS AND METHODS

Using data from the QUIPS database, the records of 5249 patients were evaluated. The total study population was divided into four groups: group 1 (10 mg oxycodone with or without naloxone 5 mg), group 2 (20 mg oxycodone with or without naloxone 10 mg), group 3 (piritramide) and group 4 (tramadol). Maximum pain intensity, pain-related interference with sleep and respiration, vomiting, postoperative fatigue, desire for more pain treatment and satisfaction with pain management were evaluated.

RESULTS AND DISCUSSION

The differences in pain intensity were statistically significant between groups. Patients with piritramide reported more pain, more interference with sleep and respiration and more fatigue compared to those from the other groups. In the group with 10 mg oxycodone, the desire for additional pain medication was the lowest. Postoperative vomiting and satisfaction with pain management differed significantly between the four groups. Procedure-specific analysis has shown that differences between sub-groups were also significant following cholecystectomy and total knee arthroplasty.

CONCLUSIONS

In summary, our findings suggest that postoperative pain treatment with slow release oral oxycodone does not show disadvantages compared to tramadol or piritramide with regard to pain-related impairments and opioid-induced side effects. This hypothesis needs to be further analyzed in controlled studies.

Management of Malignant Bowel Obstruction Associated With GI Cancers

For many patients with GI malignancies, the seeding of the abdominal cavity with tumor cells, called peritoneal carcinomatosis, is a common mode of metastases and disease progression. Prognosis for patients with this aspect of their disease remains poor, with high disease-related morbidity and complications. Uniform and proven practices that provide optimal palliative care and quality of life for these patients are needed. The objective of this review is to critically assess the current literature regarding palliative strategies in the management of peritoneal carcinomatosis and associated symptoms in patients with advanced GI cancers. Despite encouraging results in the select population where cytoreductive surgery and intraperitoneal chemotherapy are indicated, the majority of patients who develop peritoneal carcinomatosis in the setting of GI cancers have poor prognosis, with malignant bowel obstruction representing a common terminal phase of their disease process. For all patients with peritoneal carcinomatosis, aggressive symptom control and early multimodality palliative care as further outlined should be sought.

Can oliceridine (TRV130), an ideal novel µ receptor G protein pathway selective (µ-GPS) modulator, provide analgesia without opioid-related adverse reactions?

All drugs have both favorable therapeutic and untoward adverse effects. Conventional opioid analgesics possess both analgesia and adverse reactions, such as nausea, vomiting, and respiratory depression. The opioid ligand binds to µ opioid receptor and non-selectively activates two intracellular signaling pathways: the G protein pathway induce analgesia, while the β-arrestin pathway is responsible for the opioid-related adverse reactions. An ideal opioid should activate the G protein pathway while deactivating the β-arrestin pathway. Oliceridine (TRV130) has a novel characteristic mechanism on the action of the µ receptor G protein pathway selective (µ-GPS) modulation. Even though adverse reactions (ADRs) are significantly attenuated, while the analgesic effect is augmented, the some residual ADRs persist. Consequently, a G protein biased µ opioid ligand, oliceridine, improves the therapeutic index owing to increased analgesia with decreased adverse events. This review article provides a brief history, mechanism of action, pharmacokinetics, pharmacodynamics, and ADRs of oliceridine.

Analgesic Efficacy and Safety of Prolonged-Release Oxycodone/Naloxone in Korean Patients with Chronic Pain from Spinal Disorders

Background

A prolonged-release formulation of oxycodone/naloxone has been shown to be effective in European populations for the management of chronic moderate to severe pain. However, no clinical data exist for its use in Korean patients. The objective of this study was to assess efficacy and safety of prolonged-release oxycodone/naloxone in Korean patients for management of chronic moderate-to-severe pain.

Methods

In this multicenter, single-arm, open-label, phase IV study, Korean adults with moderate-to-severe spinal disorder-related pain that was not satisfactorily controlled with weak opioids and nonsteroidal anti-inflammatory drugs received prolonged-release oral oxycodone/naloxone at a starting dose of 10/5 mg/day (maximum 80/40 mg/day) for 8 weeks. Changes in pain intensity and quality of life (QoL) were measured using a numeric rating scale (NRS, 0–10) and the Korean-language EuroQol-five dimensions questionnaire, respectively.

Results

Among 209 patients assessed for efficacy, the mean NRS pain score was reduced by 25.9% between baseline and week 8 of treatment (p < 0.0001). There was also a significant improvement in QoL from baseline to week 8 (p < 0.0001). The incidence of adverse drug reactions was 27.7%, the most common being nausea, constipation, and dizziness; 77.9% of these adverse drug reactions had resolved or were resolving at the end of the study.

Conclusions

Prolonged-release oxycodone/naloxone provided significant and clinically relevant reductions in pain intensity and improved QoL in Korean patients with chronic spinal disorders. (ClinicalTrials.gov identifier: NCT01811238)

The Risk of Ischemic Cardio- and Cerebrovascular Events Associated with Oxycodone-Naloxone and Other Extended-Release High-Potency Opioids: A Nested Case-Control Study

INTRODUCTION

In Germany, an extended-release (ER) combination of the high-potency opioid (HPO) oxycodone and the antagonist naloxone was approved in 2006. In recent years, the cardio- and cerebrovascular safety of opioid antagonists and of opioids themselves has been discussed.

OBJECTIVES

The objective of this study was to estimate the risk of major ischemic cardio- and cerebrovascular events in patients receiving ER oxycodone-naloxone compared with those receiving other ER HPOs.

METHODS

We used the German Pharmacoepidemiological Research Database (GePaRD) to conduct a nested case-control study (2006-2011) within a cohort of ER HPO users. Cases were defined as patients hospitalized for acute myocardial infarction (MI) or ischemic stroke (IS). For each case, up to ten controls were selected by risk-set sampling. Using conditional logistic regression, confounder-adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were obtained for the risk of MI/IS associated with (1) current HPO treatment, (2) recent discontinuation, or (3) recent switch of HPO therapy compared with past treatment.

RESULTS

In 309,936 ER HPO users, 12,384 MI/IS events were detected, resulting in a crude incidence rate of 19.48 (95% CI 19.14-19.82) per 1000 person years. A small but significantly elevated aOR was found for morphine (1.12; 95% CI 1.04-1.22) but not for oxycodone-naloxone. Recent discontinuation and recent switch of any ER HPO also had a significant impact on the outcome (aOR 1.12; 95% CI 1.04-1.21 and 1.25; 95% CI 1.03-1.52, respectively).

CONCLUSIONS

Our study does not indicate an association between oxycodone-naloxone and ischemic cardio- or cerebrovascular events. However, our findings do suggest that every change in ER HPO therapy should be conducted with caution.

Oxycodone/Naloxone Prolonged Release: A Review in Severe Chronic Pain

Oral oxycodone/naloxone prolonged release (PR) [Targin^®, Targinact^®, Targiniq^®] is a 12-hourly opioid receptor agonist and opioid receptor antagonist fixed-dose combination product that is approved in countries in the EU for the management of severe pain (adequately manageable only with opioid analgesics) in adults. Oral naloxone prevents oxycodone from binding to μ-receptors in the gastrointestinal (GI) tract, thereby counteracting opioid-induced constipation (OIC). In short-term (5- to 12-week) clinical trials of adults with moderate to severe, chronic pain and OIC (OXN3001, OXN3006, OXN3506), oxycodone/naloxone PR significantly improved OIC while providing noninferior analgesia relative to oxycodone PR; results were consistent between cancer and non-cancer patients in OXN3506. Analgesia and improvements in bowel function were sustained with an additional 24-52 weeks of oxycodone/naloxone PR treatment in long-term extension studies. Results in real-world studies were consistent with those in clinical trials. Oxycodone/naloxone PR was generally well tolerated, with nausea, hyperhidrosis, and diarrhoea (generally transient) reported as the most commonly occurring adverse events. Thus, oxycodone/naloxone PR is a useful treatment option to consider in adults with severe chronic pain that can be adequately managed only with opioid analgesics, particularly in those with OIC.

Efficacy and safety of oxycodone/naloxone as add-on therapy to gabapentin or pregabalin for the management of chemotherapy-induced peripheral neuropathy in Korea

AIMS

To investigate the efficacy and safety of oxycodone/naloxone in patients with chemotherapy-induced peripheral neuropathy (CIPN) inadequately controlled with pregabalin or gabapentin.

METHODS

This 4-week, multicenter, interventional, single-arm phase IV study included 72 Korean patients with CIPN inadequately controlled with pregabalin or gabapentin (Numeric Rating Scale 0-10; NRS ≥4 at baseline). In addition to pregabalin or gabapentin at existing doses, patients received 20/10 mg/day oxycodone/naloxone (up-titrated to 80/40 mg/day as needed). The primary endpoint was change in NRS score after 4 weeks. Secondary endpoints included Functional Assessment of Cancer Therapy/Gynecologic Oncology Group-Neurotoxicity (FACT/GOG-NTX) scores and safety assessments.

RESULTS

The mean ± standard deviation (SD) dose of oxycodone/naloxone was 23.3 ± 7.5 mg/day. At week 4, NRS score reduction was 1.29 ± 1.84 points (21.4% reduction; P < 0.0001). Patients on taxane-based chemotherapy experienced a significantly smaller mean change in NRS score at week 4 compared to patients on other chemotherapy (-0.63 ± 1.54 [n = 30] vs. -1.83 ± 1.00 [n = 36]; P = 0.0072). Although there were no significant changes in FACT/GOG-NTX total scores, improvements were observed in the neurotoxicity subscale measuring numbness/tingling of hands (mean ± SD change: -0.27 ± 1.04; P = 0.0427) and feet (-0.60 ± 1.09; P < 0.0001). Forty-two (58.3%) patients reported adverse events. There were no clinically significant changes in laboratory tests or vital signs.

CONCLUSION

Oxycodone/naloxone added to pregabalin or gabapentin provided additional pain relief and symptom control in Korean patients with CIPN, without clinically significant safety concerns.

Prolonged-Release Oxycodone/Naloxone Improves Anal Sphincter Relaxation Compared to Oxycodone Plus Macrogol 3350

BACKGROUND

Opioid analgesics inhibit anal sphincter function and contribute to opioid-induced bowel dysfunction (OIBD). However, it is unknown whether the inhibition can be reduced by opioid antagonism with prolonged-release (PR) naloxone and how this compares to laxative treatment.

AIMS

To compare the effects of combined PR oxycodone/naloxone or PR oxycodone plus macrogol 3350 on anal sphincter function and gastrointestinal symptoms.

METHODS

A randomized, double-blind, crossover trial was conducted in 20 healthy men. Participants were treated for 5 days with combined PR oxycodone/naloxone or PR oxycodone plus macrogol 3350. Resting anal pressure, anal canal distensibility, and relaxation of the internal sphincter to rectal distension were evaluated before treatment (baseline) and on day 5. The Patient Assessment of Constipation Symptom (PAC-SYM) questionnaire, stool frequency, and stool consistency were assessed daily.

RESULTS

Both PR oxycodone/naloxone and PR oxycodone plus macrogol treatment decreased sphincter relaxation compared to baseline (- 27.5%; P < 0.001 and - 14.7%; P = 0.01). However, sphincter relaxation was increased after PR naloxone/oxycodone treatment compared to macrogol (difference = + 17.6%; P < 0.001). Resting anal pressure and anal canal distensibility did not differ between treatments. PAC-SYM abdominal symptoms score was lower during PR naloxone compared to macrogol (0.2 vs. 3.2; P = 0.002). The number of bowel movements was lower during PR naloxone versus macrogol (4.2 vs. 5.4; P = 0.035).

CONCLUSION

Relaxation of the internal anal sphincter was significantly better after PR oxycodone/naloxone treatment compared to PR oxycodone plus macrogol 3350. These findings highlight that OIBD may require specific therapy against the complex, pan-intestinal effects of opioids.

Efficacy and safety of controlled-release oxycodone/naloxone versus controlled-release oxycodone in Korean patients with cancer-related pain: a randomized controlled trial

BACKGROUND

Controlled-release oxycodone/naloxone (OXN-CR) maintains the effect of opioid-induced analgesia through oxycodone while reducing the occurrence rate of opioid-induced constipation through naloxone. The present study was designed to assess the non-inferiority of OXN-CR to controlled-release oxycodone (OX-CR) for the control of cancer-related pain in Korean patients.

METHODS

In this randomized, open-labeled, parallel-group, phase IV study, we enrolled patients aged 20 years or older with moderate to severe cancer-related pain [numeric rating scale (NRS) pain score ≥4] from seven Korean oncology/hematology centers. Patients in the intention-to-treat (ITT) population were randomized (1:1) to OXN-CR or OX-CR groups. OXN-CR was administered starting at 20 mg/10 mg per day and up-titrated to a maximum of 80 mg/40 mg per day for 4 weeks, and OX-CR was administered starting at 20 mg/day and up-titrated to a maximum of 80 mg/day for 4 weeks. The primary efficacy endpoint was the change in NRS pain score from baseline to week 4, with non-inferiority margin of -1.5. Secondary endpoints included analgesic rescue medication intake, patient-reported change in bowel habits, laxative intake, quality of life (QoL), and safety assessments.

RESULTS

Of the ITT population comprising 128 patients, 7 with missing primary efficacy data and 4 who violated the eligibility criteria were excluded from the efficacy analysis. At week 4, the mean change in NRS pain scores was not significantly different between the OXN-CR group (n = 58) and the OX-CR group (n = 59) (-1.586 vs. -1.559, P = 0.948). The lower limit of the one-sided 95% confidence interval (-0.776 to 0.830) for the difference exceeded the non-inferiority margin (P < 0.001). The OXN-CR and OX-CR groups did not differ significantly in terms of analgesic rescue medication intake, change in bowel habits, laxative intake, QoL, and safety assessments.

CONCLUSIONS

OXN-CR was non-inferior to OX-CR in terms of pain reduction after 4 weeks of treatment and had a similar safety profile. Studies in larger populations of Korean patients with cancer-related pain are needed to further investigate the effectiveness of OXN-CR for long-term pain control and constipation alleviation. Trial registration ClinicalTrials.gov NCT01313780, registered March 8, 2011.

Enhanced recovery after surgery: Pain management

Effective pain management is fundamental to enhanced recovery after surgery. Selection of strategies should be tailored to patient and operation. As well as improving the quality of recovery, effective analgesia reduces the host stress response, facilitates mobilization and allows resumption of oral intake. Multi-modal regimens combining paracetamol, non-steroidal anti-inflammatory agents where indicated, a potent opioid and a local anaesthetic technique achieve effective analgesia while limiting the dose and thereby side effects of any one agent.

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.

Luminally Acting Agents for Constipation Treatment: A Review Based on Literatures and Patents

Constipation is one of the most frequently reported gastrointestinal (GI) disorders that negatively impacts quality of life and is associated with a significant economic burden to the patients and society. Traditional treatments including lifestyle modification and laxatives are often ineffective in the more severe forms of constipation and over the long term. New medications targeting at intestinal chloride channels and colonic serotonin receptors have been demonstrated effective in recent years. Emerging agents focusing on improving intestinal secretion and/or colonic motility have been shown effective in animal models and even in clinical trials. Recognization of the role of cystic fibrosis transmembrane regulator (CFTR) and calcium-activated chloride channels (CaCCs) in intestine fluid secretion and motility modulation makes CFTR and CaCCs promising molecule targets for anti-constipation therapy. Although there are multiple choices for constipation treatment, there is still a recognized need for new medications in anti-constipation therapy. The present review covers the discovery of luminally acting agents for constipation treatment described in both patents (2011–present) and scientific literatures.

Chronic Pain: How Challenging Are DDIs in the Analgesic Treatment of Inpatients with Multiple Chronic Conditions?

Background

Chronic pain is common in multimorbid patients. However, little is known about the implications of chronic pain and analgesic treatment on multimorbid patients. This study aimed to assess chronic pain therapy with regard to the interaction potential in a sample of inpatients with multiple chronic conditions.

Methods and Findings

We conducted a retrospective study with all multimorbid inpatients aged ≥18 years admitted to the Department of Internal Medicine of University Hospital Zurich in 2011 (n = 1,039 patients). Data were extracted from the electronic health records and reviewed. We identified 433 hospitalizations of patients with chronic pain and analyzed their combinations of chronic conditions (multimorbidity). We then classified all analgesic prescriptions according to the World Health Organization (WHO) analgesic ladder. Furthermore, we used a Swiss drug-drug interactions knowledge base to identify potential interactions between opioids and other drug classes, in particular coanalgesics and other concomitant drugs. Chronic pain was present in 38% of patients with multimorbidity. On average, patients with chronic pain were aged 65.7 years and had a mean number of 6.6 diagnoses. Hypertension was the most common chronic condition. Chronic back pain was the most common painful condition. Almost 90% of patients were exposed to polypharmacotherapy. Of the chronic pain patients, 71.1% received opioids for moderate to severe pain, 43.4% received coanalgesics. We identified 3,186 potential drug-drug interactions, with 17% classified between analgesics (without coanalgesics).

Conclusions

Analgesic drugs-related DDIs, in particular opioids, in multimorbid patients are often complex and difficult to assess by using DDI knowledge bases alone. Drug-multimorbidity interactions are not sufficiently investigated and understood. Today, the scientific literature is scarce for chronic pain in combination with multiple coexisting medical conditions and medication regimens. Our work may provide useful information to enable further investigations in multimorbidity research within the scope of potential interactions and chronic pain.

Abuse-deterrent formulations of prescription opioid analgesics in the management of chronic noncancer pain

Misuse, abuse and diversion of prescription opioid analgesics represent a global public health concern. The development of abuse-deterrent formulations (ADFs) of prescription opioid analgesics is an important step toward reducing abuse and diversion of these medications, as well as potentially limiting medical consequences when misused or administered in error. ADFs aim to hinder extraction of the active ingredient, prevent administration through alternative routes and/or make abuse of the manipulated product less attractive, less rewarding or aversive. However, opioid ADFs may still be abused via the intended route of administration by increasing the dose and/or dosing frequency. The science of abuse deterrence and the regulatory landscape are still relatively new and evolving. This paper reviews the current status of opioid ADFs, with particular focus on different approaches that can be used to deter abuse, regulatory considerations and implications for clinical management.

Is there a role for opioids in the treatment of fibromyalgia?

The use of opioids for chronic pain has increased significantly due to a combination of the high patient burden of pain and the more widespread availability of a range of long-acting opioid preparations. This increased opioid use has translated into the care of many patients with fibromyalgia. The pain mechanism in fibromyalgia is complex but does not seem to involve disturbance of opioid analgesic functions. Hence, there is general concern about the harms in the absence of benefits of opioids in this setting. There is no evidence that pure opioids are effective in fibromyalgia but there is some evidence that opioids with additional actions on the norepinephrine-related pain modulatory pathways, such as tramadol, can be clinically useful in some patients. Novel actions of low-dose opioid antagonists may lead to better understanding of the role of opioid function in fibromyalgia.

Pharmacokinetic and pharmacodynamic evaluation of oxycodone and naltrexone for the treatment of chronic lower back pain

INTRODUCTION

Chronic low back pain (CLBP) is a common and difficult illness to manage. Some individuals with CLBP have pain processing disorders and are also at risk for opioid abuse, misuse; addiction and diversion. Guidelines have been published to guide management; neuromodulation, exercise, mindfulness-based stress reduction and cognitive behavior therapies among other non-pharmacological reduce the pain of CLBP with minimal toxicity. Pharmacological management includes acetaminophen, NSAIDs and antidepressants, mainly duloxetine. Abuse-deterrent opioids have been developed which have been shown to reduce pain and opioid abuse risk. ALO-02 is a tamper-resistant sustained release opioid consisting of extended release oxycodone and sequestered naltrexone. Pivotal studies of ALO-02 have centered on patients with CLBP.

AREAS COVERED

This manuscript will review CLBP, the pivotal analgesic and clinical abuse potential studies of ALO-02. The opinion will cover whether opioids should be used for CLBP, when they should be used and opioid choices.

EXPERT OPINION

ALO-02 is one of several opioids which can be considered in the management of CLBP. The outcome to a trial of opioids should be function rather than analgesia. Most analgesic trials for CLBP have had analgesia as the primary outcome and function has not been vigorously studied as an outcome. Opioids should be considered as a trial only when other non-opioid analgesics have failed to improve analgesia and function. Universal precautions should be routinely part of phase III analgesic trial particularly for chronic non-malignant pain.

Long-term efficacy and safety of oxycodone-naloxone prolonged release in geriatric patients with moderate-to-severe chronic noncancer pain: a 52-week open-label extension phase study

BACKGROUND

Two-thirds of older people suffer from chronic pain and finding valid treatment options is essential. In this 1-yearlong investigation, we evaluated the efficacy and safety of prolonged-release oxycodone-naloxone (OXN-PR) in patients aged ≥70 (mean 81.7) years.

METHODS

In this open-label prospective study, patients with moderate-to-severe noncancer chronic pain were prescribed OXN-PR for 1 year. The primary endpoint was the proportion of patients who achieved ≥30% reduction in pain intensity after 52 weeks of treatment, without worsening bowel function. The scheduled visits were at baseline (T0), after 4 weeks (T4), and after 52 weeks (T52).

RESULTS

Fifty patients completed the study. The primary endpoint was achieved in 78% of patients at T4 and 96% at T52 (P<0.0001). Pain intensity, measured on a 0-10 numerical rating scale, decreased from 6.0 at T0 to 2.8 at T4 and to 1.7 at T52 (P<0.0001). Mean daily dose of oxycodone increased from 10 to 14.4 mg (T4) and finally to 17.4 mg (T52). Bowel Function Index from 35.1 to 28.7 at T52. No changes were observed in cognitive functions (Mini-Mental State Examination evaluation), while daily functioning improved (Barthel Index from 53.1 to 61.0, P<0.0001). The Screener and Opioid Assessment for Patients with Pain-Revised score at 52 weeks was 2.6 (standard deviation 1.6), indicating a low risk of aberrant medication-related behavior. In general, OXN-PR was well tolerated.

CONCLUSION

This study of the long-term treatment of chronic pain in a geriatric population with OXN-PR shows satisfying analgesic effects achieved with a stable low daily dose, coupled with a good safety profile and, in particular, with a reduction of constipation, often present during opioid therapy. Our findings support the indications of the American Geriatrics Society, suggesting the use of opioids to treat pain in older people not responsive to acetaminophen or nonsteroidal anti-inflammatory drugs.

Analgesic drugs and the gut - a reciprocal relationship

Analgesic drugs, as well as providing pain relief, can cause a range of other symptoms and side effects, most notably on the gastrointestinal system. Conversely, gastrointestinal disease will often require analgesia, and this can be complicated by the fact that the gut is the site of absorption of oral drugs. This paper discusses some of the effects of common oral analgesic drugs on the gastrointestinal tract and their role in managing some of the most common, nonmalignant, chronic gastrointestinal disorders in adults.

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.

Management of the lower gastrointestinal system in burn: A comprehensive review

BACKGROUND

Burn produces complex gastrointestinal (GI) responses. Treatment, including large volume fluid resuscitation and opioid analgesia, may exacerbate GI dysfunction. Complications include constipation and opioid-induced bowel dysfunction (OBD), acute colonic pseudo-obstruction (ACPO), bacterial translocation and sepsis, and abdominal compartment syndrome (ACS). Contamination of perineal burns contributes to delayed healing, skin graft failure and sepsis and may impact upon morbidity and mortality. The authors carried out a literature review on management of the lower GI system in burn. This study aimed to explain: current prevention and treatment modalities; drawbacks and complications associated with available treatments, and to provide direction for development of best practice guidelines. ACS is associated with high mortality and should be treated with careful fluid resuscitation and diuresis, to minimise and remove oedema.

METHODS

A comprehensive search of English language literature was performed on PubMed, Medline and Embase. Both MeSH and keywords searches were used.

RESULTS

Evidence available on the management of lower gastrointestinal system in burn is summarised. Levels of evidence available are generally low (level III-IV).

CONCLUSION

Structured, graded interventions are required for prevention and treatment of constipation and OBD. Correction of electrolyte imbalance, adequate enteral intake and mobilisation are pre-requisites. Laxatives should be used according to World Gastroenterology Organisation recommendations. Resistant constipation may respond to changes in medication, but ACPO should be suspected and treated when present. Other complications, such as bacterial translocation and ACS are common in major burns. There is evidence that selective digestive tract decontamination reduces mortality and infectious episodes in major burns. ACS is associated with high mortality and should be treated with careful fluid resuscitation and diuresis. Surgery is reserved for non-responsive and severe cases. Perineal burns present challenges in wound and bowel management. Faecal management systems and negative pressure wound therapy (NPWT) may improve wound control and hygiene, but diversion colostomy will still be beneficial in some cases. There is a clear need for rigorous studies to guide practice more effectively in these challenging conditions.

Consensus Recommendations on Initiating Prescription Therapies for Opioid-Induced Constipation

Objective

Aims of this consensus panel were to determine (1) an optimal symptom‐based method for assessing opioid‐induced constipation in clinical practice and (2) a threshold of symptom severity to prompt consideration of prescription therapy.

Methods

A multidisciplinary panel of 10 experts with extensive knowledge/experience with opioid‐associated adverse events convened to discuss the literature on assessment methods used for opioid‐induced constipation and reach consensus on each objective using the nominal group technique.

Results

Five validated assessment tools were evaluated: the Patient Assessment of Constipation–Symptoms (PAC‐SYM), Patient Assessment of Constipation–Quality of Life (PAC‐QOL), Stool Symptom Screener (SSS), Bowel Function Index (BFI), and Bowel Function Diary (BF‐Diary). The 3‐item BFI and 4‐item SSS, both clinician administered, are the shortest tools. In published trials, the BFI and 12‐item PAC‐SYM are most commonly used. The 11‐item BF‐Diary is highly relevant in opioid‐induced constipation and was developed and validated in accordance with US Food and Drug Administration guidelines. However, the panel believes that the complex scoring for this tool and the SSS, PAC‐SYM, and 28‐item PAC‐QOL may be unfeasible for clinical practice. The BFI is psychometrically validated and responsive to changes in symptom severity; scores range from 0 to 100, with higher scores indicating greater severity and scores >28.8 points indicating constipation.

Conclusions

The BFI is a simple assessment tool with a validated threshold of clinically significant constipation. Prescription treatments for opioid‐induced constipation should be considered for patients who have a BFI score of ≥30 points and an inadequate response to first‐line interventions.

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.

Evolving paradigms in the treatment of opioid-induced bowel dysfunction

In recent years prescription of opioids has increased significantly. Although effective in pain management, bothersome gastrointestinal adverse effects are experienced by a substantial proportion of opioid-treated patients. This can lead to difficulties with therapy and subsequently inadequate pain relief. Collectively referred to as opioid-induced bowel dysfunction, these adverse effects are the result of binding of exogenous opioids to opioid receptors in the gastrointestinal tract. This leads to disturbance of three important gastrointestinal functions: motility, coordination of sphincter function and secretion. In the clinic this manifests in a wide range of symptoms such as reflux, bloating, abdominal cramping, hard, dry stools, and incomplete evacuation, although the most known adverse effect is opioid-induced constipation. Traditional treatment with laxatives is often insufficient, but in recent years a number of novel pharmacological approaches have been introduced. In this review the pathophysiology, symptomatology and prevalence of opioid-induced bowel dysfunction is presented along with the benefits and caveats of a suggested consensus definition for opioid-induced constipation. Finally, traditional treatment is appraised and compared with the latest pharmacological developments. In conclusion, opioid antagonists restricted to the periphery show promising results, but use of different definitions and outcome measures complicate comparison. However, an international working group has recently suggested a consensus definition for opioid-induced constipation and relevant outcome measures have also been proposed. If investigators within this field adapt the suggested consensus and include symptoms related to dysfunction of the upper gut, it will ease comparison and be a step forward in future research.

Is oxycodone/naloxone effective and safe in managing chronic pain of a fragile elderly patient with multiple skin ulcers of the lower limbs? A case report

Skin ulcers are a common issue in the elderly, as physiological loss of skin elasticity, alterations in microcirculation, and concomitant chronic diseases typically occur in advanced age, thereby predisposing to these painful lesions. Wound-related pain is often associated with skin ulcers and negatively impacts both the patient's quality of life and, indirectly, wound healing. Pain management is an ongoing issue in the elderly, and remains underestimated and under-treated in this fragile population. Recent guidelines suggest the use of opioids as the frontline treatment of moderate and severe pain in nononcological pain in the elderly. However, due to the concerns of adverse reactions, drug interactions, and addiction, clinicians frequently hesitate to prescribe opioids. This case report describes an elderly diabetic patient with multiple ulcers of the lower limbs suffering wound-related pain. In our report, oxycodone/naloxone has proved to be an effective and safe drug, providing pain relief as well as increased compliance when redressing wounds and faster healing compared to that in similar patients. Our case provides anecdotal evidence, supported by other studies, to justify future, larger studies on chronic pain using this therapy.

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.

Oxycodone/Naloxone PR: A Review in Severe Refractory Restless Legs Syndrome

An oral, fixed-dose combination of prolonged-release (PR) oxycodone with PR naloxone (Targin(®), Targiniq(®), Targinact(®); hereafter referred to as oxycodone/naloxone PR) is approved in Europe for the second-line symptomatic treatment of patients with severe to very severe idiopathic restless legs syndrome (RLS), after failure of dopaminergic therapy. Coadministration of naloxone represents a targeted approach to counteracting opioid-induced bowel dysfunction without compromising therapeutic efficacy; because of its very low oral bioavailability, naloxone blocks the action of oxycodone at opioid receptors locally in the gut. The efficacy of oxycodone/naloxone PR in patients with severe RLS inadequately controlled by previous (mainly dopaminergic) treatment has been demonstrated in RELOXYN, a 12-week, randomized, double-blind study with a 40-week open-label extension. In this pivotal study, oxycodone/naloxone PR significantly improved RLS symptoms compared with placebo from week 2 onwards; a beneficial effect of oxycodone/naloxone PR was maintained through 1 year of treatment. Furthermore, improvements in RLS symptoms in oxycodone/naloxone PR recipients were accompanied by similarly sustained improvements in disease-specific quality of life and subjective sleep variables. Oxycodone/naloxone PR was generally well tolerated, with a treatment-related adverse event profile (e.g. gastrointestinal disorders, CNS disorders, fatigue and pruritus) that was consistent with that expected for opioid therapy. Notably, there were no confirmed cases of augmentation among oxycodone/naloxone PR recipients throughout the course of the study. Results from the well-designed RELOXYN trial have thus demonstrated the value of oxycodone/naloxone PR as a second-line therapy for severe refractory RLS; further investigation of this combination product as a first-line treatment for severe RLS is now warranted.

[Update on oncological pain in the elderly]

Pain is a prevalent symptom in cancer geriatric patients, appearing in up to 90% of patients with terminal cancer. This requires a multidimensional approach, as there is a high percentage of inappropriate assessments and treatments. Unrecognized or poorly treated pain in the geriatric population, especially in cancer patients, leads to the development of disabling symptoms such as depression, anxiety, isolation, sleep disturbances, and appetite, and very especially, loss of functional capacity and quality of life. In this review an analysis is made on the most relevant studies on the diagnosis and management of cancer pain in the geriatric population.

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.

Pain management of the cancer patient

INTRODUCTION

Cancer pain is one of the most important symptoms of malignant disease, which has a major impact on the quality of life of cancer patients. Therefore, it needs to be treated appropriately after a careful assessment of the types and causes of pain.

AREAS COVERED

The mainstay of cancer pain management is systemic pharmacotherapy. This is, in principle, still based on the WHO guidelines initially published in 1986. Although these have been validated, they are not evidence-based. The principles are a stepladder approach using non-opioids, weak and then strong opioids. In addition, adjuvants can be added at any step to address specific situations such as bone or neuropathic pain. Patients, even if they are on long-acting opioids, need to be provided with immediate-release opioids for breakthrough pain. In case of inefficacy or severe adverse effects of one opioid, rotation to another opioid is recommended.

EXPERT OPINION

There is a major need for more and better randomized controlled trials in the setting of cancer pain as the lack of evidence is hampering the improvement of current treatment guidelines.

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.

Clinical potential of naloxegol in the management of opioid-induced bowel dysfunction

Opioid-induced bowel dysfunction (OIBD) is a burdensome condition which limits the therapeutic benefit of analgesia. It affects the entire gastrointestinal tract, predominantly by activating opioid receptors in the enteric nervous system, resulting in a wide range of symptoms, such as reflux, bloating, abdominal cramping, hard, dry stools, and incomplete evacuation. The majority of studies evaluating OIBD focus on constipation experienced in approximately 60% of patients. Nevertheless, other presentations of OIBD seem to be equally frequent. Furthermore, laxative treatment is often insufficient, which in many patients results in decreased quality of life and discontinuation of opioid treatment. Novel mechanism-based pharmacological approaches targeting the gastrointestinal opioid receptors have been marketed recently and even more are in the pipeline. One strategy is prolonged release formulation of the opioid antagonist naloxone (which has limited systemic absorption) and oxycodone in a combined tablet. Another approach is peripherally acting, μ-opioid receptor antagonists (PAMORAs) that selectively target μ-opioid receptors in the gastrointestinal tract. However, in Europe the only PAMORA approved for OIBD is the subcutaneously administered methylnaltrexone. Alvimopan is an oral PAMORA, but only approved in the US for postoperative ileus in hospitalized patients. Finally, naloxegol is a novel, oral PAMORA expected to be approved soon. In this review, the prevalence and pathophysiology of OIBD is presented. As PAMORAs seem to be a promising approach, their potential effect is reviewed with special focus on naloxegol's pharmacological properties, data on safety, efficacy, and patient-focused perspectives. In conclusion, as naloxegol is administered orally once daily, has proven efficacious compared to placebo, has an acceptable safety profile, and can be used as add-on to existing pain treatment, it is a welcoming addition to the targeted treatment possibilities for OIBD.