The use of opioid analgesics for chronic pain: minimizing the risk for harm

Chemoenzymatic Synthesis of Optically Active Ethereal Analog of iso-Moramide-A Novel Potentially Powerful Analgesic †

To develop potent and safer analgesics, we designed and synthesized a novel enantiomerically enriched ethereal analog of (R)-iso-moramide, namely 2-[(2R)-2-(morpholin-4-yl)propoxy]-2,2-diphenyl-1-(pyrrolidin-1-yl)ethan-1-one. The titled active agent can potentially serve as a powerful synthetic opiate with an improved affinity and selectivity toward opioid receptors (ORs). This hypothesis was postulated based on docking studies regarding the respective complexes between the designed ligand and µ-OR, δ-OR, and κ-OR. The key step of the elaborated asymmetric synthesis of novel analog involves lipase-catalyzed kinetic resolution of racemic 1-(morpholin-4-yl)propan-2-ol, which was accomplished on a 10 g scale via an enantioselective transesterification employing vinyl acetate as an irreversible acyl donor in tert-butyl methyl ether (MTBE) as the co-solvent. Next, the obtained homochiral (S)-(+)-morpholino-alcohol (>99% ee) was functionalized into corresponding chloro-derivative using thionyl chloride (SOCl2) or the Appel reaction conditions. Further transformation with N-diphenylacetyl-1-pyrrolidine under phase-transfer catalysis (PTC) conditions using O2-saturated DMSO/NaOH mixture as an oxidant furnished the desired levorotatory isomer of the title product isolated in 26% total yield after three steps, and with 89% ee. The absolute configuration of the key-intermediate of (R)-(−)-iso-moramide was determined using a modified form of Mosher’s methodology. The preparation of the optically active dextrorotatory isomer of the titled product (87% ee) was carried out essentially by the same route, utilizing (R)-(−)-1-(morpholin-4-yl)propan-2-ol (98% ee) as a key intermediate. The spectroscopic characterization of the ethereal analog of iso-moramide and the enantioselective retention relationship of its enantiomers using HPLC on the cellulose-based chiral stationary phase were performed. Moreover, as a proof-of-principle, single-crystal X-ray diffraction (XRD) analysis of the synthesized 2-[(2R)-2-(morpholin-4-yl)propoxy]-2,2-diphenyl-1-(pyrrolidin-1-yl)ethan-1-one is reported.

Mind-body approaches targeting the psychological aspects of opioid use problems in patients with chronic pain: evidence and opportunities

Opioids are commonly prescribed for the management of patients with chronic noncancer pain. Despite the potential analgesic benefits of opioids, long-term opioid therapy (LTOT) may be accompanied by problems such as opioid misuse and opioid use disorder (OUD). In this review, we begin with a description of opioid misuse and OUD and the patient-specific factors associated with these problems among patients with chronic pain. We will focus primarily on highlighting the predominant role played by psychological factors in the occurrence of opioid misuse and OUD in these patients. Several psychological factors have been found to be associated with opioid use problems in patients with chronic pain, and evidence indicates that patients presenting with psychological disturbances are particularly at risk of transitioning to long-term opioid use, engaging in opioid misuse behaviors, and developing OUD. The biological factors that might underlie the association between psychological disturbances and opioid use problems in patients with chronic pain have yet to be fully elucidated, but a growing number of studies suggest that dysfunctions in reward, appetitive, autonomic, and neurocognitive systems might be involved. We end with an overview of specific types of psychological interventions that have been put forward to prevent or reduce the occurrence of opioid misuse and OUD in patients with chronic pain who are prescribed LTOT.

Sedative, analgesic, behavioral and clinical effects of intravenous nalbuphine-xylazine combination in camels (Camelus dromedarius)

This study examined the sedative, analgesic, behavioral, and clinical effects of a combination of xylazine (XY) and nalbuphine-xylazine (NA-XY) in camels. A total of five adult camels were used in a prospective randomized cross-over design with a wash out period of two weeks. Camels were allocated randomly to two treatment groups: the XY group (xylazine, 1.1mL/100 kg IV) and the NA-XY group (xylazine, 1.1mL/100 kg IV and nalbuphine, 1 mg/kg IV). The sedative, analgesic, behavioral, and clinical effects of XY and NA-XY combination were evaluated prior to administration (baseline) and at 5, 15, 30, 45, 60, 75, 90, and 120 minutes post-administration. The results showed that the NA-XY combination accelerates the onset of sedation and analgesia and prolongs the durations of both sedation (p < 0.001) and analgesia (p < 0.01). The behavioral parameters showed higher scores with a NA-XY combination than xylazine alone. Although a XY injection resulted in a significant decline in the heart and respiratory rate, the NA-XY combination group revealed a non-significant change in both clinical parameters compared to the baseline. In conclusion, the use of a NA-XY combination in camels improved the sedative and analgesic onset and duration with an improved outcome in the behavioral scores, as well as in both the heart and respiratory rates compared to XY alone.

The prescription opioid conundrum: 21st century solutions to a millennia-long problem

Health-care professionals are faced with a daunting task: balancing appropriate care for chronic pain with their responsibility to keep patients and others safe from treatment-related harm. Whereas opioids have historically been considered an effective tool in the analgesic armamentarium, the rise of opioid abuse has caused the pendulum to swing away from prescribing opioids to an emphasis on safety. This paradigm shift risks neglecting the very real consequences of untreated/undertreated pain. Using data from the medical literature, this review examines influences on the real and perceived benefit-to-risk ratio for opioids and provides clinicians with a practical approach to prescribing opioids that minimizes the risk for abuse/misuse. There is appreciable clinical trial and observational evidence of efficacy/effectiveness with opioids used for pain management over the short or long term when considered in the context of pharmacologic alternatives. Enhancing the relative safety and minimizing the risk for abuse/misuse may be achieved through proactive prescription practices that include careful patient selection, risk assessment, individualized and multimodal treatment plans with established goals, initiating opioid treatment cautiously with an exit plan in place, ongoing assessments of response to therapy, and routine patient monitoring. Additionally, prescribing opioids with a lower potential for abuse or misuse (e.g. abuse-deterrent formulations) may provide a benefit. Using a pragmatic approach to prescribing practices, we postulate that the balance between benefit and risk can be favorable for opioid therapy in select patients, even for long-term treatment of chronic pain.

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 application of nalbuphine in patient-controlled intravenous analgesia for patients undergoing subtotal gastrectomy

The aim of the present study was to investigate the analgesic effect and safety of the application of different doses of nalbuphine in patient-controlled intravenous analgesia (PCIA) for patients undergoing subtotal gastrectomy. A total of 120 patients, who underwent subtotal gastrectomy at our hospital between May, 2015 and January, 2017 under combined spinal epidural combined anesthesia, were selected. The patients received PCIA after surgery. The patients were randomly divided into four groups, including the morphine (MOP group), nalbuphine 60 mg (N60 group), nalbuphine 80 mg (N80 group) and nalbuphine 100 mg (N100 group). The first dose of PCIA treatment was 2 ml, the background dose was 2 ml/h, PCIA dose was 0.5 ml, and the lockout time was 15 min. Postoperative vital signs and adverse reactions (bleeding, fullness and aching of upper abdomen and vomiting) were recorded. The visual analogue scale (VAS) and Ramsay sedation score of patients were evaluated. The number of PCIA and analgesia-related complications during analgesia were recorded. No significant differences in general data were found among the four groups (P>0.05). The VAS score of the three nalbuphine groups was lower than that of the MOP group, but the differences were not significant. All postoperative Ramsay sedation scores of the four groups showed appropriate sedation, but no significant differences were found between the groups. Compared with the MOP group, the use of postoperative PCIA was significantly delayed and the number of PCIA was significantly smaller in the three nalbuphine groups (P<0.05). The results show that the analgesic effect and safety of the use of PCIA for patients undergoing subtotal gastrectomy were satisfactory.

Strategies to Identify and Reduce Opioid Misuse Among Patients with Gastrointestinal Disorders: A Systematic Scoping Review

BACKGROUND

Scoping reviews are preliminary assessments intended to characterize the extent and nature of emerging research evidence, identify literature gaps, and offer directions for future research. We conducted a systematic scoping review to describe published scientific literature on strategies to identify and reduce opioid misuse among patients with gastrointestinal (GI) symptoms and disorders.

METHODS

We performed structured keyword searches to identify manuscripts published through June 2016 in the PubMed MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Scopus, and Web of Science databases to extract original research articles that described healthcare practices, tools, or interventions to identify and reduce opioid misuse among GI patients. The Chronic Care Model (CCM) was used to classify the strategies presented.

RESULTS

Twelve articles met the inclusion criteria. A majority of studies used quasi-experimental or retrospective cohort study designs. Most studies addressed the CCM's clinical information systems element. Seven studies involved identification of opioid misuse through prescription drug monitoring and opioid misuse screening tools. Four studies discussed reductions in opioid use by harnessing drug monitoring data and individual care plans, and implementing self-management and opioid detoxification interventions. One study described drug monitoring and an audit-and-feedback intervention to both identify and reduce opioid misuse. Greatest reductions in opioid misuse were observed when drug monitoring, self-management, or audit-and-feedback interventions were used.

CONCLUSION

Prescription drug monitoring and self-management interventions may be promising strategies to identify and reduce opioid misuse in GI care. Rigorous, empirical research is needed to evaluate the longer-term impact of these strategies.

The Dorsal Root Ganglion as a Therapeutic Target for Chronic Pain

Chronic neuropathic pain is a widespread problem with negative personal and societal consequences. Despite considerable clinical neuroscience research, the goal of developing effective, reliable, and durable treatments has remained elusive. The critical role played by the dorsal root ganglion (DRG) in the induction and maintenance of chronic pain has been largely overlooked in these efforts, however. It may be that, by targeting this site, robust new options for pain management will be revealed. This review summarizes recent advances in the knowledge base for DRG-targeted treatments for neuropathic pain:• Pharmacological options including the chemical targeting of voltage-dependent calcium channels, transient receptor potential channels, neurotrophin production, potentiation of opioid transduction pathways, and excitatory glutamate receptors.• Ablation or modulation of the DRG via continuous thermal radiofrequency and pulsed radiofrequency treatments.• Implanted electrical neurostimulator technologies.• Interventions involving the modification of DRG cellular function at the genetic level by using viral vectors and gene silencing methods.

Rethinking chronic pain in a primary care setting

Chronic pain substantially impacts patient function and quality of life and is a burden to society at large in terms of increased health care utilization and loss of productivity. As a result, there is an increasing recognition of chronic pain as a public health crisis. However, there remains wide variability in clinical practices related to the prevention, assessment, and treatment of chronic pain. Certain fundamental aspects of chronic pain are often neglected including the contribution of the psychological, social, and contextual factors associated with chronic pain. Also commonly overlooked is the importance of understanding the likely neurobiological mechanism(s) of the presenting pain and how they can guide treatment selection. Finally, physicians may not recognize the value of using electronic medical records to systematically capture data on pain and its impact on mood, function, and sleep. Such data can be used to monitor onset and maintenance of treatments effects at the patient level and evaluate costs at the systems level. In this review we explain how these factors play a critical role in the development of a coordinated, evidence-based treatment approach tailored to meet specific needs of the patient. We also discuss some practical approaches and techniques that can be implemented by clinicians in order to enhance the assessment and management of individuals with chronic pain in primary care settings.

Development of functionalized hollow microporous organic capsules encapsulating morphine – an in vitro and in vivo study

Carboxylic group functionalized hollow microporous organic capsules (HMOCs) are synthesized that show extraordinary high encapsulation efficiency of morphine·HCl and its promising prolonged release.

Pharmacotherapies in Geriatric Chronic Pain Management

Pharmacologic management of chronic pain in older adults is one component of the multimodal, interdisciplinary management of this complex condition. In this article, we summarize several of the key barriers to effective pharmacologic management in older adults and review the existing (albeit limited) evidence for its effectiveness and safety, especially in a medically complex population with multimorbidity. This review covers topical formulations, acetaminophen, oral nonsteroidal antiinflammatory drugs, and adjuvant therapies. The article concludes with a suggested approach to managing chronic pain in the older patient, incorporating goals and expectations for treatment as well as careful monitoring of medication adjustments.

Management of Pain Associated with Selected Conditions in Dermatology

Dermatologists face a wide range of pain control challenges in daily practice, from the transient pain of dermatologic surgery to the persistent pain that plagues some chronic dermatologic conditions. Although the pathophysiology of pain is well described and the profound impact of dermatological pain on patients' quality of life is well appreciated, there is an identified need for clear therapeutic plans for providing symptomatic pain relief of common painful dermatoses. In this paper, we will review and clearly outline approaches to pain management of a number of common painful dermatoses such as herpes zoster and post-herpetic neuralgia, ulcers, oral dermatoses, dysesthesias, and many others.

No evidence of potentiation of buprenorphine by milnacipran in healthy subjects using a nociceptive test battery

BACKGROUND

Serotonin-norepinephrine reuptake inhibitors inhibit the reuptake of serotonin and noradrenalin and are used in the treatment of neuropathic pain. Animal studies suggest that milnacipran co-administered with opioids may potentiate the analgesic effect of μ-opioid receptor agonists. This study hypothesized that co-administration of milnacipran and buprenorphine would have a synergistic effect in evoked pain models in healthy subjects.

METHODS

This was a randomized double-blinded, placebo-controlled, four-way cross-over, multiple dose clinical trial to investigate the analgesic effects of buprenorphine (placebo, 0.5, 1 and 3 μg/kg) in combination with milnacipran (placebo, 25 and 50 mg) in healthy subjects.

RESULTS

11 healthy men were enrolled in the study. Buprenorphine alone showed a dose-response relationship indicative of anti-nociception in the pain tests. Following milnacipran administration, no changes were seen in the pharmacodynamic measurements for pain, psychomotor function, body stability or eye movements. For the electrical tests, cold pressor test and pressure pain test, buprenorphine alone was superior when compared with buprenorphine plus milnacipran. No differences in pharmacodynamic variables, besides an increase in pupil/iris ratio, were observed after repeated administration of milnacipran 50 mg. Single and multiple doses of 25 or 50 mg milnacipran did not further potentiate the anti-nociceptive effects of buprenorphine.

CONCLUSIONS

Buprenorphine showed dose-dependent effects consistent with its pharmacological profile. Milnacipran alone did not affect any of the pain variables. The combination of both buprenorphine and milnacipran did not potentiate or show a synergistic effect on the pain models used in this study.

SIGNIFICANCE

Buprenorphine is known to be a potent opioid agonist. Animal studies suggest that milnacipran co-administered with opioids may potentiate the analgesic effect of μ-opioid receptor agonists. Here, we found that buprenorphine showed a dose-dependent analgesic effect, but that no potentiation or synergy on a battery of evoked pain tasks could be observed after co-administration of both milnacipran and buprenorphine.

The Use of Low Level Laser Therapy (LLLT) For Musculoskeletal Pain

Pain is the most common reason for physician consultation in the United States. One out of three Americans is affected by chronic pain annually. The number one reason for missed work or school days is musculoskeletal pain. Currently accepted therapies consist of non-steroidal anti-inflammatory drugs, steroid injections, opiate pain medications and surgery, each of which carries their own specific risk profiles. What is needed are effective treatments for pain which have an acceptably low risk-profile. For over forty years, low level laser (light) therapy (LLLT) and LED (light emitting diode) therapy (also known as photobiomodulation) has been shown to reduce inflammation and edema, induce analgesia, and promote healing in a range of musculoskeletal pathologies. The purpose of this paper is to review the use of LLLT for pain, the biochemical mechanisms of action, the dose response curves, and how LLLT may be employed by orthopedic surgeons to improve outcomes and reduce adverse events. With the predicted epidemic of chronic pain in developed countries, it is imperative to validate cost-effective and safe techniques for managing painful conditions which would allow people to live active and productive lives. Moreover the acceptance of LLLT (which is currently being used by many specialties around the world) into the armamentarium of the American health care provider would allow for additional treatment options for patients. A new cost-effective therapy for pain could elevate quality of life while reducing financial strains.

Mindfulness-based stress reduction (MBSR) as sole intervention for non-somatisation chronic non-cancer pain (CNCP): protocol for a systematic review and meta-analysis of randomised controlled trials

INTRODUCTION

Chronic non-cancer pain (CNCP) affects up to 50% of the world's population. It impacts negatively on quality of life; entailing high costs on our medical systems, and translates to economic burden due to work loss. Aetiology of CNCP is complex and multifactorial, embracing the somatosensory, cognitive and affective domains. Opioid analgesia and other invasive interventions are often inadequate for clinical management of CNCP. Recently, mindfulness-based stress reduction (MBSR) has become a popular therapy for various medical conditions, including CNCP. However, studies reported varying efficacies, and relevant systematic reviews have included clinical trials with inherent heterogeneity either in study conditions or types of interventions used. Our study aims to provide an updated and more critical evaluation of the efficacy of MBSR as the intervention for non-somatisation CNCP.

METHODS AND ANALYSIS

A systematic review with meta-analysis of randomised controlled trials published in English will be performed in accordance with the Preferred Reporting Items for Systematic reviews and Meta-analyses (PRISMA) guidelines and the Cochrane Collaboration format. MEDLINE, EMBASE, PsychINFO, and the Cochrane Central Register of Controlled Trials Intervention, will be searched independently by reviewers using defined MeSH terms. Studies with full texts using MBSR as the main intervention on patients with non-somatising CNCP will be included. Outcome measures include pain scores and disability assessment scales. Continuous data will be meta-analysed using the RevMan 5 Review Manager programme. Primary analysis will adopt the random effects model in view of heterogeneity between trials. The standardised mean difference will be expressed as the effect size with 95% CIs. Forest plots, funnel plots, the I(2) statistic and the Cochrane Risks of Bias Assessment table will be included.

ETHICS AND DISSEMINATION

No ethics approval is deemed necessary. Results of this study will be disseminated via peer-reviewed publications and scientific meetings.

TRIALS REGISTRATION NUMBER

PROSPERO CRD42014015568.