Gabapentin for Neuropathic Cancer Pain: A Randomized Controlled Trial From the Gabapentin Cancer Pain Study Group

Opioid analgesics for nociceptive cancer pain: A comprehensive review

Pain is one of the most burdensome symptoms in people with cancer, and opioid analgesics are considered the mainstay of cancer pain management. For this review, the authors evaluated the efficacy and toxicities of opioid analgesics compared with placebo, other opioids, nonopioid analgesics, and nonpharmacologic treatments for background cancer pain (continuous and relatively constant pain present at rest), and breakthrough cancer pain (transient exacerbation of pain despite stable and adequately controlled background pain). They found a paucity of placebo-controlled trials for background cancer pain, although tapentadol or codeine may be more efficacious than placebo (moderate-certainty to low-certainty evidence). Nonsteroidal anti-inflammatory drugs including aspirin, piroxicam, diclofenac, ketorolac, and the antidepressant medicine imipramine, may be at least as efficacious as opioids for moderate-to-severe background cancer pain. For breakthrough cancer pain, oral transmucosal, buccal, sublingual, or intranasal fentanyl preparations were identified as more efficacious than placebo but were more commonly associated with toxicities, including constipation and nausea. Despite being recommended worldwide for the treatment of cancer pain, morphine was generally not superior to other opioids, nor did it have a more favorable toxicity profile. The interpretation of study results, however, was complicated by the heterogeneity in the study populations evaluated. Given the limited quality and quantity of research, there is a need to reappraise the clinical utility of opioids in people with cancer pain, particularly those who are not at the end of life, and to further explore the effects of opioids on immune system function and quality of life in these individuals.

An overview of the current drug treatment strategies for moderate to severe, chronic malignant tumor-related pain

INTRODUCTION

The pharmacological management of cancer pain is a complex issue that requires knowledge and experience in the use of analgesics. The aim of this expert review is to provide a panorama of the pharmacological strategies in cancer pain management.

AREAS COVERED

Opioid dose titration is a delicate process regarding the start of opioid treatment in different clinical conditions. How to improve the opioid response is a fundamental step, which includes different strategies when an initial treatment with opioids fails. The use of adjuvants is another relevant issue that should be considered in some specific circumstances to optimize the management of cancer pain management. Some clinical conditions, such as neuropathic pain and breakthrough pain, deserve a special attention. Relevant literature was selected to provide an overview of cancer pain management strategies.

EXPERT OPINION

Opioid therapy still remains the cornerstone of pharmacological management of cancer pain. Opioids should be used according to the level of tolerance, also personalizing the treatment (route, drug, and dosing). Adjuvant drugs may help in specific conditions, although their use should be balanced with the adverse effects. Breakthrough pain requires expertise in tailoring a treatment according to patient's profile and characteristics of episodes.

Assessing the effectiveness of gabapentin in paclitaxel-induced arthralgia, myalgia, and neuropathic pain: An observational, cohort study

BACKGROUND AND OBJECTIVES

Arthralgia, myalgia, and neuropathic pain are the most common side effects observed due to paclitaxel chemotherapy. The aim of this study was to investigate the prophylactic role, maintenance, remission, and re-occurrence of arthralgia, myalgia, and neuropathic pain post-gabapentin therapy.

METHODOLOGY

This study was conducted in the Department of Oncology, Dhiraj Hospital, Vadodara with a sample of 51 patients. Newly detected cancer patients who observed arthralgia, myalgia, and neuropathic pain due to paclitaxel were taken and a baseline pain assessment was done using the Common Terminology Criteria for Adverse Events (CTCAE) and painDETECT questionnaire. Gabapentin was given in the first cycle after symptoms appeared and prophylactic treatment was given in the subsequent three cycles and evaluation of pain was done post-gabapentin therapy to assess the symptomatic as well as prophylactic effect.

RESULTS

At baseline, neuropathic pain score was 22.7 ± 3.6 which reduced to 0.01 ± 0.14 on subsequent follow-ups. Grade 2 arthralgia, myalgia, and neuropathic pain were more observed at baseline which reduces to Grade 0 in the third cycle. The difference in baseline and post-gabapentin therapy was statistically analyzed by conducting t-test which showed p-value <0.00001 and t-value was less than -2 which indicated a statistically significant result.

CONCLUSION

This study shows that gabapentin reduces neuropathic pain. Prophylactic usage of gabapentin was highly effective at bringing about quick pain relief when compared to symptomatic treatment. In further follow-ups, it was noted that gabapentin maintained the impact throughout the cycles.

Lidocaine for Neuropathic Cancer Pain (LiCPain): study protocol for a mixed-methods pilot study

INTRODUCTION

Many patients experience unrelieved neuropathic cancer-related pain. Most current analgesic therapies have psychoactive side effects, lack efficacy data for this indication and have potential medication-related harms. The local anaesthetic lidocaine (lignocaine) has the potential to help manage neuropathic cancer-related pain when administered as an extended, continuous subcutaneous infusion. Data support lidocaine as a promising, safe agent in this setting, warranting further evaluation in robust, randomised controlled trials. This protocol describes the design of a pilot study to evaluate this intervention and explains the pharmacokinetic, efficacy and adverse effects evidence informing the design.

METHODS AND ANALYSIS

A mixed-methods pilot study will determine the feasibility of an international first, definitive phase III trial to evaluate the efficacy and safety of an extended continuous subcutaneous infusion of lidocaine for neuropathic cancer-related pain. This study will comprise: a phase II double-blind randomised controlled parallel-group pilot of subcutaneous infusion of lidocaine hydrochloride 10% w/v (3000 mg/30 mL) or placebo (sodium chloride 0.9%) over 72 hours for neuropathic cancer-related pain, a pharmacokinetic substudy and a qualitative substudy of patients' and carers' experiences. The pilot study will provide important safety data and help inform the methodology of a definitive trial, including testing proposed recruitment strategy, randomisation, outcome measures and patients' acceptability of the methodology, as well as providing a signal of whether this area should be further investigated.

ETHICS AND DISSEMINATION

Participant safety is paramount and standardised assessments for adverse effects are built into the trial protocol. Findings will be published in a peer-reviewed journal and presented at conferences. This study will be considered suitable to progress to a phase III study if there is a completion rate where the CI includes 80% and excludes 60%. The protocol and Patient Information and Consent Form have been approved by Sydney Local Health District (Concord) Human Research Ethics Committee 2019/ETH07984 and University of Technology Sydney ETH17-1820.

TRIAL REGISTRATION NUMBER

ANZCTR ACTRN12617000747325.

Combination pharmacotherapy for the treatment of neuropathic pain in adults: systematic review and meta-analysis

ABSTRACT

Neuropathic pain causes substantial morbidity and healthcare utilization. Monotherapy with antidepressants or anticonvulsants often fails to provide relief. Combining different drugs sometimes provides improved analgesia and/or tolerability. More than half of patients receive 2 or more analgesics, and combination trials continue to emerge. This review comprehensively searched CENTRAL, MEDLINE, and EMBASE for relevant trials. Included studies are double-blind randomized controlled trials evaluating combinations of 2 or more drugs vs placebo or at least one monotherapy in adults with neuropathic pain. Outcomes included measures of efficacy and adverse effects. Risk of bias was assessed. Meta-analyses compared combination to monotherapy wherever 2 or more similar studies were available. Forty studies (4741 participants) were included. Studies were heterogenous with respect to various characteristics, including dose titration methods and administration (ie, simultaneous vs sequential) of the combination. Few combinations involved a nonsedating drug, and several methodological problems were identified. For opioid-antidepressant, opioid-gabapentinoid, and gabapentinoid-antidepressant combinations, meta-analyses failed to demonstrate superiority over both monotherapies. In general, adverse event profiles were not substantially different for combination therapy compared with monotherapy. Despite widespread use and a growing number of trials, convincing evidence has not yet emerged to suggest superiority of any combination over its respective monotherapies. Therefore, implementing combination therapy-as second- or third-line treatment-in situations where monotherapy is insufficient, should involve closely monitored individual dosing trials to confirm safety and overall added benefit. Further research is needed, including trials of combinations involving nonsedating agents, and to identify clinical settings and specific combinations that safely provide added benefit.

Chronic postsurgical pain in children and young adults with cancer and choice of regional anesthesia for amputation and limb-sparing surgery

BACKGROUND

Patients undergoing limb amputation (LA) or limb-sparing (LS) for lower extremity oncologic diagnoses are at similar risk for chronic postsurgical pain of neuropathic nature (CPSP/NP). Regional anesthesia (RA) techniques are pre-emptive measures to prevent the occurrence of the CPS/NP. However, recommendations for epidural (EP) versus peripheral nerve blocks (PNBs) lack in pediatric literature.

AIMS

This study investigates the incidence and duration of CPSP/NP and describes NP-directed regimens.

METHODS AND RESULTS

Data on demographics, use of EP or PNB, duration of CPSP/NP, and NP-directed medication were retrospectively collected for LA and LS between 2009 and 2019. Mixed effects logistic regression was used to compare the odds of CPSP/NP between EP and PNB. Cox PH model with adjustment for clustering due to multiple surgeries on patients was used to quantify rate of pain relief between surgery groups (LA vs. LS) and RA groups (EP vs. PNB). The incidence of CPSP/NP was 36 (23.8%) after 165 surgeries (150 patients). The odds of CPSP/NP after PNB were 2.5 times those of CPSP/NP after EP (p = .11). The rate of pain relief at any instant after the EP was 1.2 times that after PNB (p = .3). The rate of pain relief for LS with EP was 1.9 times that of pain relief for LA with EP, a statistically significant difference (p = .03). Gabapentin was used (94.5%), with addition of amitriptyline (24.2%) and both amitriptyline and methadone (12.7%).

CONCLUSION

The LS with the EP group had a significantly higher rate of relief of CPSP/NP than LA with EP. Odds of CPSP/NP after PNB were 2.5 times those of CPSP after EP.

Head and Neck Cancer-Related Pain

Pain is a common and most debilitating symptom of head and neck cancers (HNC). The prevalence of pain in HNC is nearly 70%. There are no universally accepted classification or diagnostic criteria for HNC-related pain, and currently, HNC-related pain is classified based on the underlying pathophysiological mechanism, the location of the tumor, and the protagonist of pain. The clinical presentation of HNC-related pain varies and can be similar to primary pain disorders. The management of HNC-related pain primarily consists of pharmacotherapy. However, in some cases, interventions may be needed. This article will present a case study and review the epidemiology, diagnostic criteria and classification, clinical features, pathophysiology, and HNC-related pain management.

Determining massage dose-response to improve cancer-related symptom cluster of pain, fatigue, and sleep disturbance: A 7-arm randomized trial in palliative cancer care

BACKGROUND

The efficacy of various massage doses in palliative cancer care settings is still debated, and no specific protocol is available.

AIM

Evaluating response to various massage doses for symptom cluster of pain-fatigue-sleep.

DESIGN

A 7-arm randomized-controlled trial with weekly massage for 4 weeks depending on the prescribed dose (15-, 30-, or 60-min; 2× or 3×/week) and a 4-week follow-up. The intensities of pain, fatigue, and sleep disturbance were measured using a 0-10 scale at nine-timepoint; baseline, weekly during the intervention, and the follow-up period. Then, the mean scores of the three symptoms were calculated as the symptom cluster intensity at each timepoint. IRCT.ir IRCT20150302021307N5.

SETTING/PARTICIPANTS

Adults with cancer (n = 273) who reported all three symptoms at three oncology centers in Iran.

RESULTS

The odds of clinical improvement (at least 30% reduction in symptom cluster intensity from baseline) increased with dose-escalation significantly [(OR = 17.37; 95% CI = 3.87-77.90 for 60-min doses); (OR = 11.71; 95% CI = 2.60-52.69, for 30-min doses); (OR = 4.36; 95% CI = 0.94-20.32, for 15-min doses)]. The effect durability was significantly shorter at 15-min doses compared to 30- and 60-min doses. The odds of improvement for doses 3×/week was not significant compared to doses 2×/week (OR = 12.27 vs OR = 8.34); however, the effect durability for doses 3×/week was significantly higher.

CONCLUSIONS

The findings indicated that dose-escalation increases the efficacy of massage for the pain-fatigue-sleep symptom cluster. Although the 60-min doses were found to be more effective, the 30-min doses can be considered more practical because they are less costly and time-consuming. Our findings can be helpful to develop massage guidelines in palliative care settings.

TRIAL REGISTRATION

Iranian Registry of Clinical Trials, IRCT20150302021307N5.

Risk of major adverse events associated with gabapentinoid and opioid combination therapy: A systematic review and meta-analysis

Background: The use of opioid-gabapentinoid combinations has increased, raising several safety concerns. However, meta-analysis studies focusing on this issue are limited. Objective: To evaluate the risk of central nervous system (CNS) depression, gastrointestinal (GI) adverse events, and mortality of combination therapy compared with those of opioid therapy and to explore the differences in the results according to study design and indications. Methods: Relevant studies were selected (published before 30 January 2022) by searching the MEDLINE, Embase, and CENTRAL databases. The pooled odds ratios (OR) with 95% confidence intervals (CI) of the outcomes were estimated using the Mantel-Haenszel method. Subgroup and meta-regression analyses were performed according to study characteristics. Quality assessment was conducted using the Risk of Bias 2 tool for randomized controlled trials (RCTs) and Cochrane Collaboration's Risk of Bias in non-RCTs tool for non-randomized trials. Results: Adverse events were reported in 26 RCTs and 7 non-RCTs, and mortality was reported in 10 non-RCTs. Compared to opioid therapy, dizziness, cognitive dysfunction, and respiratory depression in combination therapy significantly increased in non-RCTs (OR 3.26, 95% CI 1.82-5.85; OR 3.13, 95% CI 1.51-6.50; OR 1.71, 95% CI 1.31-2.24, respectively), and a similar trend for dizziness and cognitive dysfunction was also identified in the RCT analysis, although the difference was not significant. Combination therapy for cancer pain was associated with the highest risk of sedation in subgroup analysis. Combination therapy significantly decreased the risk of GI adverse events, including nausea, vomiting, and constipation. The mortality risk associated with combination therapy was higher than that associated with opioid therapy (OR 2.76, 95% CI 1.26-6.05). Conclusion: Opioid-gabapentinoid combination therapy could be associated with an increased risk of CNS depression and mortality, despite tolerable GI adverse events. These data suggest that combination therapy requires close monitoring of CNS depression, especially in cancer patients. Caution is needed in interpreting the clinical meanings owing to the lack of risk difference in respiratory depression in the RCT-only analysis and the absence of RCT or prospective studies investigating mortality.

Treatment of Neuropathic Pain Directly Due to Cancer: An Update

Simple Summary

This review discusses treatment approaches for providing pain relief to oncological patients affected by pain caused by nerve damage due to the tumor, also known as neuropathic cancer pain. Although being encountered often and causing a relevant burden to these patients, neuropathic cancer pain remains still difficult to diagnose and treat. Strong evidence about the best drugs to be used remain limited, as do therapeutic choices.

Abstract

Neuropathic pain can be defined as pain related to abnormal somatosensory processing in either the peripheral or central nervous system. In this review article, with neuropathic cancer pain (NCP), we refer to pain due to nervous tissue lesions caused by the tumor or its metastases. Nervous tissue damage is the cause of cancer pain in approximately 40% of those experiencing cancer pain. Recognizing a neuropathic pathophysiology in these cases may be difficult and requires specific criteria that are not homogenously applied in clinical practice. The management of this type of pain can be challenging, requiring the use of specific non-opioid adjuvant drugs. The majority of the criteria for NCP diagnosis and management have been based mainly on results from the noncancer population, risking the failure of addressing the specific needs of this population of patients. In this review, we summarize current management options available for NCP and provide some insights on new promising treatments.

Revision of Pharmacological Treatment Recommendations for Cancer Pain: Clinical Guidelines from the Japanese Society of Palliative Medicine

Background: Pain is one of the most common symptoms in cancer patients. The Japanese Society for Palliative Medicine (JSPM) first published its clinical guidelines for the management of cancer pain in 2010. Since then, more research on cancer pain management has been reported, and new drugs have become available in Japan. Thus, the JSPM has now revised the clinical guidelines using a validated methodology. Methods: This guideline was developed through a systematic review, discussion, and the Delphi method, following a formal guideline development process. Results: Thirty-five recommendations were created: 19 for the pharmacological management of cancer pain, 6 for the management of opioid-induced adverse effects, and 10 for pharmacological treatment procedures. Due to the lack of evidence that directly addressed our clinical questions, most of the recommendations had to be based on consensus among committee members and other guidelines. Discussion: It is critical to continue to build high-quality evidence in cancer pain management, and revise these guidelines accordingly.

Interventional and Non-interventional Medical Rehabilitation Approaches to Axial Spine Pain in Vertebral Metastatic Disease

As targeted therapies help patients with advanced cancer live longer, interventions for management of axial spine pain will become more common. Unfortunately, the indications for and safety of these procedures have been relatively unexplored compared with non-cancer adults. This review focuses on the following aspects of axial spine pain management in patients with vertebral metastatic disease: (1) pathophysiology and symptoms of cancer- and non-cancer-related spine pain; (2) safety and efficacy of non-interventional rehabilitation approaches to treat this pain; (3) considerations for interventional pain approaches to acute and chronic pain in patients with vertebral metastatic disease. This review also summarizes gaps in the literature and describes specific cases in which the described interventions have been applied.

Nonopioid drug combinations for cancer pain: a systematic review

Supplemental Digital Content is Available in the Text.

This review is an evaluation of the efficacy and safety of nonopioid drug combinations for cancer pain. Little evidence exists to support the use of any given agent/combination.

Pain is highly prevalent in patients with cancer—nearly 40% report moderate-severe pain, which is commonly treated with opioids. Increasing cancer survivorship, opioid epidemics in some regions of the world, and limited opioid access in other regions have focused attention on nonopioid treatments. Given the limitations of monotherapy, combining nonopioids—such as antiepileptics and antidepressants—have shown promise in noncancer pain. This review seeks to evaluate efficacy of nonopioid combinations for cancer-related pain. Systematic searches of PubMed, EMBASE, and Cochrane CENTRAL were conducted for double-blind, randomized, controlled trials comparing a nonopioid combination with at least one of its components and/or placebo. This search yielded 4 randomized controlled trials, published between 1998 and 2019 involving studies of (1) imipramine + diclofenac; (2) mitoxantrone + prednisone + clodronate; (3) pentoxifylline + tocopherol + clodronate; and (4) duloxetine + pregabalin + opioid. In the first 3 of these trials, trends favouring combination efficacy failed to reach statistical significance. However, in the fourth trial, duloxetine + pregabalin + opioid was superior to pregabalin + opioid. This review illustrates recognition for the need to evaluate nonopioid drug combinations in cancer pain, although few trials have been published to date. Given the growing practice of prescribing more than 1 nonopioid for cancer pain and the need to expand the evidence base for rational combination therapy, more high-quality trials in this area are needed.

Phase III, international, multicentre, double-blind, dose increment, parallel-arm, randomised controlled trial of duloxetine versus pregabalin for opioid-unresponsive neuropathic cancer pain: a JORTC-PAL16 trial protocol

INTRODUCTION

Management of neuropathic cancer pain (NCP) refractory to regular opioids remains an important challenge. The efficacy of pregabalin for NCP except chemotherapy-induced peripheral neuropathy (CIPN) has already been confirmed in two randomised controlled trials (RCTs) compared with placebo. Duloxetine offers the potential of analgesia in opioid refractory NCP. However, there are no RCT of duloxetine for the management of opioid-refractory NCP as a first line treatment. Both classes of drugs have the potential to reduce NCP, but there has been no head-to-head comparison for the efficacy and safety, especially given differing side effect profiles.

METHODS AND ANALYSIS

An international, multicentre, double-blind, dose increment, parallel-arm, RCT is planned. Inclusion criteria include: adults with cancer experiencing NCP refractory to opioids; Brief Pain Inventory (BPI)-item 3 (worst pain) of ≥4; Neuropathic Pain on the Leeds Assessment of Neuropathic Symptoms and Signs Pain Scale of ≥12 despite of an adequate trial of regular opioid medication (≥60 mg/day oral morphine equivalent dose). Patients with CIPN are excluded.The study will recruit from palliative care teams (both inpatients and outpatients) in Japan and Australia. Participants will be randomised (1:1 allocation ratio) to duloxetine or pregabalin arm. Dose escalation is until day 14 and from day 14 to 21 is a dose de-escalation period to avoid withdrawal effects. The primary endpoint is defined as the mean difference in BPI item 3 for worst pain intensity over the previous 24 hours at day 14 between groups. A sample size of 160 patients will be enrolled between February 2020 and March 2023.

ETHICS AND DISSEMINATION

Ethics approval was obtained at Osaka City University Hospital Certified Review Board and South Western Sydney Local Health District Human Research Ethics Committee. The results of this study will be submitted for publication in international journals and the key findings presented at international conferences. TRIAL REGISTRATION NUMBERS: jRCTs051190097, ACTRN12620000656932.

Analgesic Effect of SH003 and Trichosanthes kirilowii Maximowicz in Paclitaxel-Induced Neuropathic Pain in Mice

Pacliatxel is a taxol-based chemotherapeutic drug that is widely used to treat cancer. However, it can also induce peripheral neuropathy, which limits its use. Although several drugs are prescribed to attenuate neuropathies, no optimal treatment is available. Thus, in our study, we analyzed whether SH003 and its sub-components could alleviate paclitaxel-induced neuropathic pain. Multiple paclitaxel injections (cumulative dose 8 mg/kg, i.p.) induced cold and mechanical allodynia from day 10 to day 21 after the first injection in mice. Oral administration of SH003, an herbal mixture extract of Astragalus membranaceus, Angelica gigas, and Trichosantheskirilowii Maximowicz (Tk), dose-dependently attenuated both allodynia. However, when administered separately only Tk decreased both allodynia. The effect of Tk was shown to be mediated by the spinal noradrenergic system as intrathecal pretreatment with α₁- and α₂-adrenergic-receptor antagonists (prazosin and idazoxan), but not 5-HT_1/2, and 5-HT₃-receptor antagonists (methysergide and MDL-72222) blocked the effect of Tk. The spinal noradrenaline levels were also upregulated. Among the phytochemicals of Tk, cucurbitacin D was shown to play a major role, as 0.025 mg/kg (i.p.) of cucurbitacin D alleviated allodynia similar to 500 mg/kg of SH003. These results suggest that Tk should be considered when treating paclitaxel-induced neuropathic pain.

Mirogabalin Decreases Pain-like Behaviours and Improves Opioid and Ketamine Antinociception in a Mouse Model of Neuropathic Pain

Neuropathic pain remains a difficult clinical challenge due to its diverse aetiology and complex pathomechanisms, which are yet to be fully understood. Despite the variety of available therapies, many patients suffer from ineffective pain relief; hence, the search for more efficacious treatments continues. The new gabapentinoid, mirogabalin has recently been approved for clinical use. Although its main mechanism of action occurs at the α2σ-1 and α2σ-2 subunits of calcium channels and is well documented, how the drug affects the disturbed neuropathic interactions at the spinal cord level has not been clarified, which is crucial information from a clinical perspective. The findings of our study suggest that several indirect mechanisms may be responsible for the beneficial analgesic effect of mirogabalin. This is the first study to report that mirogabalin enhances the mRNA expression of spinal antinociceptive factors, such as IL-10 and IL-18BP, and reduces the concentration of the pronociceptive substance P. Importantly, mirogabalin improves the morphine-, buprenorphine-, oxycodone-, and ketamine-induced antinociceptive effects in a neuropathic pain model. Our findings support the hypothesis that enhancing opioid and ketamine analgesia by combining these drugs with mirogabalin may represent a new strategy for the effective pharmacotherapy of neuropathic pain.

Establishment of a research policy for supportive and palliative care in Japan

Background

While several small groups in Japan have attempted to conduct prospective studies in the field of supportive and palliative care, development of exploratory research into multicentre confirmatory studies has been difficult. The main reason for this is the difference in clinical research methodology in supportive and palliative care compared with medical oncology in terms of the style of multidisciplinary approaches, study design and endpoints. Here, we establish a new research policy for cancer supportive and palliative care in Japan.

Methods

The first draft was developed by a policy working group within the Japanese Supportive, Palliative and Psychosocial Care Study Group. A provisional draft was subsequently developed after review by nine Japanese scientific societies (Japanese Association of Supportive Care in Cancer, Japanese Society of Medical Oncology, Japanese Society of Clinical Oncology, Japanese Society of Palliative Medicine, Japanese Society of Cancer Nursing, Japanese Society of Pharmaceutical Oncology (JASPO), Japan Cancer Association (JCA), Japanese Society of Therapeutic Radiation Oncology and Japanese Cancer Association) and receipt of public comments. The final research policy in the area of supportive and palliative care in Japan (Ver1.0) was completed in December 2018 and underwent its first revision (Ver1.1) in February, 2020.

Results

The policy includes the following components of clinical research: (i) objective of the research policy in the areas of supportive and palliative care; (ii) definitions of supportive care and palliative care; (iii) characteristics of supportive and palliative care research; (iv) target population for research; (v) research design; (vi) endpoints and assessment measures; (vii) handling of the deaths of subjects and (viii) operational structure and quality management.

Conclusions

We hope that studies conducted according to this policy will play important roles in the future development of the supportive and palliative field.

Neuropathic pain: clinical classification and assessment in patients with pain due to cancer

ABSTRACT

Neuropathic cancer pain (NcP) is associated with worse treatment responses and specific therapy indications, but a standardized clinical diagnosis of NcP is still lacking. This is a prospective observational study on outpatients with cancer, comparing different clinical approaches with NcP evaluation. A three-step assessment of NcP was performed using DN4 (cutoff of 4), palliative care physician Clinical Impression, including etiology and pain syndrome identification, and Retrospective Clinical Classification by a board of specialists with the IASP Neuropathic Pain Special Interest Group criteria. Neuropathic cancer pain classification was specifically referred to pain directly due to cancer. Three hundred fifty patients were assessed, and NcP prevalence was 20% (95% confidence interval [CI] 15.9%-24.6%), 36.9%, (95% CI 31.6%-42.1%), and 28.6% (95% CI 23.8%-33.9%) according to DN4, Clinical Impression, and Retrospective Clinical Classification, respectively. Cohen's kappa concordance coefficient between DN4 and Retrospective Clinical Classification was 0.57 (95% CI 0.47-0.67), indicating moderate concordance. Higher percentages of discordance were found for specific pain syndromes such as pain due to deep soft tissue infiltration and pain associated with tenesmus. Disagreement among clinicians accounted also for different NcP diagnoses and highlighted lack of homogeneous clinical criteria. Rigorous application of etiological and syndrome diagnosis to explain pain cause, associated with standardized diagnostic criteria and assessment of pain characteristics, that is also specific for the cancer pain condition could improve clinical classification of NcP.

Non-opioid Analgesics and Emerging Therapies

Pain is a common and debilitating symptom of cancer. Cancer-related pain can occur at any point along the continuum from diagnosis to treatment to survivorship¹. A systematic review published in 2016 estimated the prevalence of cancer pain to be 55% in those undergoing antineoplastic treatment, 66.4% in advanced cancer, and 39.3% in the post-treatment population. Thirty-eight percent of cancer patients in this pooled analysis experienced moderate to severe pain².

Effectiveness of Gabapentinoids for Cancer-related Rectal and Vesical Tenesmus: Report of Four Cases

Gabapentinoids could be assumed to relieve cancer-related rectal/vesical tenesmus based on their pharmacological mechanism. Four patients were refractory for cancer-related rectal/vesical tenesmus although their opioid doses were titrated up. Symptom intensity difference (SID) between initiation and follow-up after 24, 48, and 72 h and daily changes in the frequency of urination, defecation, opioid rescue doses, presence of sleep disruption, and dose of regular opioid medication were evaluated. The median reductions in daily discomfort measured as SID between baseline and follow-up after 24, 48, and 72 h were 87.5%, 70.0%, and 80.0%, respectively, while those in daily pain intensity were 75%, 66.7%, and 66.7%, respectively. The initiation dose of gabapentin was 200 or 400 mg/day and that of pregabalin was 75 mg/day in one patient. Gabapentinoids were effective at low doses administered over a short duration to patients with refractory cancer-related rectal/vesical tenesmus.

Drug Screening and Drug Repositioning as Promising Therapeutic Approaches for Spinal Muscular Atrophy Treatment

Spinal muscular atrophy (SMA) is the most common genetic disease affecting infants and young adults. Due to mutation/deletion of the survival motor neuron (SMN) gene, SMA is characterized by the SMN protein lack, resulting in motor neuron impairment, skeletal muscle atrophy and premature death. Even if the genetic causes of SMA are well known, many aspects of its pathogenesis remain unclear and only three drugs have been recently approved by the Food and Drug Administration (Nusinersen-Spinraza; Onasemnogene abeparvovec or AVXS-101-Zolgensma; Risdiplam-Evrysdi): although assuring remarkable results, the therapies show some important limits including high costs, still unknown long-term effects, side effects and disregarding of SMN-independent targets. Therefore, the research of new therapeutic strategies is still a hot topic in the SMA field and many efforts are spent in drug discovery. In this review, we describe two promising strategies to select effective molecules: drug screening (DS) and drug repositioning (DR). By using compounds libraries of chemical/natural compounds and/or Food and Drug Administration-approved substances, DS aims at identifying new potentially effective compounds, whereas DR at testing drugs originally designed for the treatment of other pathologies. The drastic reduction in risks, costs and time expenditure assured by these strategies make them particularly interesting, especially for those diseases for which the canonical drug discovery process would be long and expensive. Interestingly, among the identified molecules by DS/DR in the context of SMA, besides the modulators of SMN2 transcription, we highlighted a convergence of some targeted molecular cascades contributing to SMA pathology, including cell death related-pathways, mitochondria and cytoskeleton dynamics, neurotransmitter and hormone modulation.

Nonopioid drug combinations for cancer pain: protocol for a systematic review

This protocol will guide a review of clinical trials that evaluate the efficacy and safety of nonopioid analgesic drug combinations for the management of cancer-related pain.

Introduction:

Pain related to cancer, and its treatment, is common, may severely impair quality of life, and imposes a burden on patients, their families and caregivers, and society. Cancer-related pain is often challenging to manage, with limitations of analgesic drugs including incomplete efficacy and dose-related adverse effects.

Objectives:

Given problems with, and limitations of, opioid use for cancer-related pain, the identification of nonopioid treatment strategies that could improve cancer pain care is an attractive concept. The hypothesis that combinations of mechanistically distinct analgesic drugs could provide superior analgesia and/or fewer adverse effects has been tested in several pain conditions, including in cancer-related pain. Here, we propose to review trials of nonopioid analgesic combinations for cancer-related pain.

Methods:

Using a predefined literature search strategy, trials—comparing the combination of 2 or more nonopioid analgesics with at least one of the combination's individual components—will be searched on the PubMed and EMBASE databases from their inception until the date the searches are run. Outcomes will include pain intensity or relief, adverse effects, and concomitant opioid consumption.

Results/Conclusions:

This review is expected to synthesize available evidence describing the efficacy and safety of nonopioid analgesic combinations for cancer-related pain. Furthermore, a review of this literature will serve to identify future research goals that would advance our knowledge in this area.

Additive Duloxetine for Cancer-Related Neuropathic Pain Nonresponsive or Intolerant to Opioid-Pregabalin Therapy: A Randomized Controlled Trial (JORTC-PAL08)

CONTEXT

Although opioids and pregabalin are widely used for cancer-related neuropathic pain (CNP), no clinical trials exist to determine which medications are effective when an opioid-pregabalin combination therapy fails.

OBJECTIVES

We investigated the efficacy of duloxetine for CNP nonresponsive or intolerant to opioid-pregabalin combination therapy.

METHODS

A multicenter, randomized, double-blind, placebo-controlled trial was performed at 12 specialized palliative care services in Japan. Patients with CNP average pain scores (Brief Pain Inventory [BPI]-Item 5) ≥ 4 in the previous 24 hours and nonresponsive or intolerant to opioid-pregabalin combination therapy were eligible. Patients with chemotherapy-induced peripheral neuropathies were excluded. Patients were administered duloxetine 20 mg/day titrated to 40 mg/day or placebo for 10 days. The primary endpoint was BPI-Item 5 on Day 10. Responder analysis measured proportions of patients with 30% and 50% pain decreases.

RESULTS

Seventy patients were enrolled. Complete case analysis revealed mean BPI-Item 5 on Day 10 of 4.03 for Group D vs. 4.88 for Group P (P = 0.053). Baseline observation carried forward analysis revealed mean BPI-Item 5 on Day 10 of 4.06 and 4.91 for Groups D and P, respectively (P = 0.048). Clinically meaningful pain improvement (≥30%) was reported by 44.1% (n = 15) of patients in Group D vs. 18.2% (n = 6) in Group P (P = 0.02); 32.4% (n = 11) vs. 3.0% (n = 1) of patients in Groups D and P, respectively, reported pain reduction ≥ 50% (P = 0.002).

CONCLUSION

Adding duloxetine to opioid-pregabalin therapy might have clinical benefit in alleviating refractory CNP. Further studies are needed to conclude the efficacy of adding duloxetine.

Adult Cancer Pain, Version 3.2019, NCCN Clinical Practice Guidelines in Oncology

In recent years, the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Adult Cancer Pain have undergone substantial revisions focusing on the appropriate and safe prescription of opioid analgesics, optimization of nonopioid analgesics and adjuvant medications, and integration of nonpharmacologic methods of cancer pain management. This selection highlights some of these changes, covering topics on management of adult cancer pain including pharmacologic interventions, nonpharmacologic interventions, and treatment of specific cancer pain syndromes. The complete version of the NCCN Guidelines for Adult Cancer Pain addresses additional aspects of this topic, including pathophysiologic classification of cancer pain syndromes, comprehensive pain assessment, management of pain crisis, ongoing care for cancer pain, pain in cancer survivors, and specialty consultations.

Short-Term Effects of 10% Lidocaine Ointment on Allodynia in Cancer Pain: A Randomized, Double-Blind, Placebo-Controlled Crossover Study

Background: There is currently no established therapy for allodynia, which is a type of neuropathic pain. However, high concentrations of topical anesthetics can anesthetize the skin and increase the sensory threshold to tactile stimulation. Objective: We aimed to evaluate the short-term effects and safety of 10% lidocaine ointment for treating allodynia in cancer pain. Design: This was a randomized double-blind crossover study comparing the efficacies of 10% lidocaine ointment and placebo ointment for the treatment of static allodynia and spontaneous pain within 24 hours after ointment application, using a numerical rating scale (NRS). Setting/Subjects: The subjects were 25 cancer patients with current pain rating of ≥4 on NRS of static allodynia in cancer pain. Results: The NRS scores for static allodynia were significantly lower in the lidocaine group than in the placebo group at two to eight hours after initial ointment application. A total of 56% of patients (95% confidence interval 35%-77%) had NRS improvements of ≥50% at eight hours after lidocaine ointment application compared with 20% (3%-37%) after placebo ointment application. There was no interaction between time and group in terms of NRS values for spontaneous pain (p = 0.835), but a significant main effect of group was found, with NRS scores being significantly lower in the lidocaine group than in the placebo group (p = 0.027). There were no adverse events associated with lidocaine use. Conclusions: Lidocaine ointment 10% can alleviate allodynia for two to eight hours after application.

A critical appraisal of gabapentinoids for pain in cancer patients

PURPOSE OF REVIEW

Gabapentinoids are frequently used in the management of cancer pain. In recent Cochrane systematic reviews, although there was an abundance of evidence relating to non-cancer pain, only a few studies related to cancer pain. This review summarizes recent randomised controlled trials (RCTs) evaluating the use of gabapentinoids for tumour-related (as monotherapy or part of combination therapy) and treatment-related pain.

RECENT FINDINGS

For tumour-related pain, ten out of thirteen studies showed statistically significant benefits in favour of gabapentinoids. When used, as part of monotherapy or combination therapy, benefits were observed in five out of six studies evaluating gabapentin, and in six out of eight studies evaluating pregabalin. For treatment-related pain, none of the four studies (two gabapentin, two pregabalin) showed statistically significant benefits in favour of gabapentinoids. Unfortunately, many of the studies included were limited by small sample size, lack of blinding, and inadequate follow-up.

SUMMARY

More and better quality studies are required, although it may be challenging to accomplish in this patient population. Gabapentinoids may offer benefits to cancer patients with pain, but careful titration and monitoring of adverse effects is necessary.

Attitude of Japanese palliative care specialists towards adjuvant analgesics cancer-related neuropathic pain refractory to opioid therapy: a nationwide cross-sectional survey

Cancer-related neuropathic pain (CNP) requires therapy involving multiple pharmaceuticals, including anticonvulsants and antidepressants; however, strong evidence to support this practice is limited. This study is a cross-sectional questionnaire-based survey. As the standard dose of adjuvant analgesics for CNP refractory to opioid therapy is not clear, the purpose of this study is to clarify the opinions of specialists about the usage of duloxetine and pregabalin for patients with CNP refractory to opioid therapy. Two hundred and eight certified palliative care specialists were surveyed and a total of 87 (42%) responses were analyzed. Twenty-five percent of specialists had considered increasing duloxetine doses up to 60 mg/day and 58% had considered increasing pregabalin doses up to 300 mg/day for CNP refractory to opioid therapy. However, 23% of the specialists succeeded in increasing duloxetine doses up to 60 mg/day and 17% in increasing pregabalin doses up to 300 mg/day, respectively.

Neuropathic Pain in Pediatric Oncology: A Clinical Decision Algorithm

Neuropathic pain in pediatric oncology can be caused by distinct lesions or disease processes affecting the somatosensory system, including chemotherapy-related neuronal injury, solid tumor-related involvement of neural structures, post-surgical neuropathic pain-including phantom limb pain and pain after limb-sparing surgery-and the complex circumstances of neuropathic pain at the end of life. Treatment algorithms reflect the general treatment principles applied for adult neuropathic pain, but the dose regimens applied in children are modest and rarely escalated to the maximum doses to optimize analgesic efficacy. Pharmacological management of neuropathic pain should be based on a stepwise intervention strategy, as combinations of medications are the most effective approach. Gabapentinoids and tricyclic antidepressants are recommended as first-line therapy. Methadone, ketamine, and lidocaine may be useful adjuvants in selected patients. Prospective studies extended over a substantial length of time are recommended because of the nature of neuropathic pain as persistent, chronic pain and based on the need for sufficient time to escalate medication dose regimens to full analgesic efficacy.

Microneurosurgical treatment options in peripheral nerve compression syndromes after chemotherapy and radiation treatment

Chemotherapy-induced peripheral neuropathy and radiation-induced brachial plexopathy are extremely debilitating conditions which can occur after treatment of malignancy. Unfortunately, the diagnosis can be elusive, and this dilemma is further compounded by the lack of efficacious therapeutics to prevent the onset of neurotoxicity before initiating chemotherapy or radiation or to treat these sequelae after treatment. However, microsurgical nerve decompression can provide these patients with a viable option to treat this complication.

Cancer-Related Neuropathic Pain: Review and Selective Topics

Neuropathic pain is the result of neuroplastic and neuroinflammatory changes from trauma or diseases that damage the somatosensory system. Cancer-related neuropathic pain is caused by treatment, cancer, or paraneoplastic reactions to cancer. Approximately 30% of patients with cancer have neuropathic pain, mostly mixed nociceptive and neuropathic pain. History, physical examination, quantitative sensory testing, skin punch biopsies, and functional MRIs help to divide pain into phenotypes that may facilitate analgesic choices. Guidelines for treating cancer-related neuropathic pain are not consistent and are highly dependent on trials in patients without cancer. Combinations of analgesics are promising, whereas evidence for cannabinoids is meager.

High-Intensity Ultrasound Treatment for Vincristine-Induced Neuropathic Pain

BACKGROUND

Vincristine is a commonly used chemotherapeutic agent that results in debilitating untreatable peripheral neuropathy.

OBJECTIVE

To determine the effects of pulsed high-intensity focused ultrasound (HIFU) on sensory thresholds in a validated vincristine-induced neuropathy (VIN) rodent model.

METHODS

VIN was induced and mechanical allodynia was confirmed by nociceptive testing. von Frey fibers and Randall-Sellito test were used as measures of innocuous and noxious mechanical thresholds, respectively, and the hot plate test for thermal thresholds. Tests were performed before VIN, after 2 wk of vincristine, at 24, 48, 72, and 120 h after HIFU applied to the left L5 dorsal root ganglia at 3 Watts for 3 min. Comparisons were made between a VIN cohort who underwent HIFU, a VIN cohort who underwent sham HIFU, and naïve rodents who underwent HIFU.

RESULTS

VIN HIFU rats had significantly increased mechanical thresholds at 24 h (P &lt; .001), 48 h (P = .008), 72 h (P = .003), and 120 h (P = .03) after treatment, when compared to pre-HIFU thresholds. Furthermore, at 24 and 48 h following treatment, VIN HIFU rats had significantly higher innocuous and noxious mechanical thresholds and thermal thresholds than VIN sham HIFU rats (P &lt; .001). Thresholds were not altered in naïve rodents who underwent HIFU. Histological data of L5 dorsal root ganglia of VIN HIFU rats suggest that transient cellular edema resolves by 48 h.

CONCLUSION

Our data suggest that HIFU increases mechanical and thermal thresholds in VIN rodents. Whether HIFU can preclude the development of reduced thresholds in the VIN model warrants further study.

Opioids combined with antidepressants or antiepileptic drugs for cancer pain: Systematic review and meta-analysis

BACKGROUND

Combining antidepressant or antiepileptic drugs with opioids has resulted in increased pain relief when used for neuropathic pain in non-cancer conditions. However, evidence to support their effectiveness in cancer pain is lacking.

AIM

To determine if there is additional benefit when opioids are combined with antidepressant or antiepileptic drugs for cancer pain.

DESIGN

Systematic review and meta-analysis. Randomised control trials comparing opioid analgesia in combination with antidepressant or antiepileptic drugs versus opioid monotherapy were sought. Data on pain and adverse events were extracted. Data were pooled using DerSimonian-Laird random-effects meta-analyses, and heterogeneity was assessed.

RESULTS

Seven randomised controlled trials that randomised 605 patients were included in the review. Patients' pain was described as neuropathic cancer pain, cancer bone pain and non-specific cancer pain. Four randomised controlled trials were included in the meta-analysis in which opioid in combination with either gabapentin or pregabalin was compared with opioid monotherapy. The pooled standardised mean difference was 0.16 (95% confidence interval, -0.19, 0.51) showing no significant difference in pain relief between the groups. Adverse events were more frequent in the combination arms. Data on amitriptyline, fluvoxamine and phenytoin were inconclusive.

CONCLUSION

Combining opioid analgesia with gabapentinoids did not significantly improve pain relief in patients with tumour-related cancer pain compared with opioid monotherapy. Due to the heterogeneity of patient samples, benefit in patients with definite neuropathic cancer pain cannot be excluded. Clinicians should balance the small likelihood of benefit in patients with tumour-related cancer pain against the increased risk of adverse effects of combination therapy.

Anticonvulsants or Antidepressants in Combination Pharmacotherapy for Treatment of Neuropathic Pain in Cancer Patients: A Systematic Review and Meta-analysis

OBJECTIVE

To investigate the efficacy of anticonvulsants or antidepressants in combination pharmacotherapy for treatment of neuropathic pain in cancer patients.

MATERIALS AND METHODS

We systematically searched the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, and the metaRegister of Controlled Trials for randomized controlled trials that compared anticonvulsants or antidepressants in combination pharmacotherapy (experimental group) with treatments without anticonvulsants or antidepressants (control group) for neuropathic pain in cancer patients. Risk of bias was evaluated in accordance with the Cochrane Handbook for Systematic Reviews of Interventions. The primary outcome was a mean difference (MD) in change in global pain analyzed by a random-effects model.

RESULTS

Eight trials met the inclusion criteria with a total of 1359 participants of whom 698 received an experimental intervention. The MD in change in global pain suggested a favorable association with anticonvulsants or antidepressants in combination pharmacotherapy compared with control groups (MD, -0.41; 95% confidence interval, -0.70 to -0.12) with no heterogeneity across trials (I=0%). The MD in change estimated in all sensitivity analyses ranged from -0.36 to -0.47, suggesting that these effects were consistent across different study designs and statistical assumptions.

CONCLUSIONS

Anticonvulsants or antidepressants in combination pharmacotherapy reduce neuropathic pain in cancer patients compared with treatments without anticonvulsants or antidepressants. Limited evidence precludes a recommendation on specific adjuvants in combination pharmacotherapy.

The efficacy of combination treatment of gabapentin and electro-acupuncture on paclitaxel-induced neuropathic pain

Paclitaxel, a chemotherapeutic drug, induces severe peripheral neuropathy. Gabapentin (GBT) is a first line agent used to treat neuropathic pain, and its effect is mediated by spinal noradrenergic and muscarinic cholinergic receptors. Electro-acupuncture (EA) is used for treating various types of pain via its action through spinal opioidergic and noradrenergic receptors. Here, we investigated whether combined treatment of these two agents could exert a synergistic effect on paclitaxel-induced cold and mechanical allodynia, which were assessed by the acetone drop test and von Frey filament assay, respectively. Significant signs of allodynia were observed after four paclitaxel injections (a cumulative dose of 8 mg/kg, i.p.). GBT (3, 30, and 100 mg/kg, i.p.) or EA (ST36, Zusanli) alone produced dose-dependent anti-allodynic effects. The medium and highest doses of GBT (30 and 100 mg/kg) provided a strong analgesic effect, but they induced motor dysfunction in Rota-rod tests. On the contrary, the lowest dose of GBT (3 mg/kg) did not induce motor weakness, but it provided a brief analgesic effect. The combination of the lowest dose of GBT and EA resulted in a greater and longer effect, without inducing motor dysfunction. This effect on mechanical allodynia was blocked by spinal opioidergic (naloxone, 20 μg), or noradrenergic (idazoxan, 10 μg) receptor antagonist, whereas on cold allodynia, only opioidergic receptor antagonist blocked the effect. In conclusion, the combination of the lowest dose of GBT and EA has a robust and enduring analgesic action against paclitaxel-induced neuropathic pain, and it should be considered as an alternative treatment method.

Study protocol for a multi-institutional, randomised, double-blinded, placebo-controlled phase III trial investigating additive efficacy of duloxetine for neuropathic cancer pain refractory to opioids and gabapentinoids: the DIRECT study

INTRODUCTION

Management of patients with cancer suffering from neuropathic pain refractory to opioids and gabapentinoids remains an important challenge. Duloxetine is one of the choices after first-line treatment fails. The efficacy of duloxetine has been reported in patients with non-cancer disease and in chemotherapy-induced peripheral neuropathy, but no randomised clinical trials have examined its effects on neuropathic cancer pain refractory to first-line treatment. The objective of this study is to assess the analgesic efficacy of duloxetine in patients suffering from neuropathic cancer pain refractory to opioids and gabapentinoids.

METHODS AND ANALYSIS

A multi-institutional, prospective, randomised, double-blind, placebo-controlled, two-parallel trial is planned. The inclusion criteria are adult patients with cancer suffering from neuropathic cancer pain refractory to opioids and gabapentinoids, patients with a Numerical Rating Scale (NRS) pain score of 4 or higher and patients with a total Hospital Anxiety and Depression Scale score of less than 20. Patients with chemotherapy-induced peripheral neuropathy are excluded. The study will take place at 14 sites across Japan. Participants will be randomised (1:1 allocation ratio) to a duloxetine intervention group or a placebo control group. Evaluations will be made at baseline (T0 randomisation), day 0 (T1), day 3 (T2) and day 10 (T3). The primary endpoint is defined as the difference in NRS score for pain intensity (average over the previous 24 hours) at T3 between the duloxetine and placebo groups. A sample size of 70 patients will be examined between July 2015 and March 2018.

ETHICS AND DISSEMINATION

Ethics approval was obtained at all participating sites.The results of this study will be submitted for publication in international peer-reviewed journals and the key findings presented at international scientific conferences.

TRIAL REGISTRATION NUMBER

UMIN000017647; Pre-results.

PROTOCOL VERSION

2.2, 26 April 2017.

Gabapentin in the Management of Pain following Tonsillectomy: A Randomized Double-Blind Placebo-Controlled Trial

Objective To determine if a single dose of oral gabapentin given prior to tonsillectomy decreases postoperative morbidity. Study Design Prospective randomized double-blind placebo-controlled trial. Setting Southern District Health Board University Hospitals, New Zealand, over a 10-month period. Subjects and Methods Seventy-three adults undergoing tonsillectomy were randomized to receive either a single preoperative dose of oral gabapentin (600 mg) or placebo. A standard analgesic protocol was prescribed for 14 postoperative days. The primary outcome was a patient-assigned visual analog scale pain score during rest and swallow; secondary outcomes were analgesic consumption, nausea, vomiting, and return to normal diet and activities. Complications and adverse effects were also recorded. Results Thirty-seven participants were allocated to the placebo group and 36 to the gabapentin group. After withdrawals, data were analyzed from 31 in the placebo group and 27 in the gabapentin group. Pain scores between groups were not significantly different within the first 6 hours. The gabapentin group recorded significantly higher pain scores between days 5 and 10 (maximal difference, day 8: 17.6 mm; effect size, -8.87; P = .03; 95% CI, -16.883 to -0.865). There was no significant difference in swallow pain scores or early postoperative fentanyl consumption. Consumption of paracetamol ( P = .01 at day 13 and P = .004 at day 14) and codeine ( P < .05 at days 3-5, 7, 8, 10, 14) was higher in the gabapentin group. No significant difference between groups was found for the other outcomes. Conclusions Preemptive gabapentin (600 mg) was associated with greater postoperative pain scores and analgesic consumption following adult tonsillectomy when compared with placebo.

Combination treatment of neuropathic pain: Danish expert recommendations based on a Delphi process

BACKGROUND

Current Danish treatment algorithms for pharmacological treatment of neuropathic pain (NeP) are tricyclic antidepressants (TCA), gabapentin and pregabalin as first-line treatment for the most common NeP conditions. Many patients have insufficient pain relief on monotherapy, but combination therapy had not been included in guidelines until recently. Based on clinical empiricism and scientific evidence, a Delphi consensus process provided a consolidated guidance on pharmacological combination treatment of NeP.

METHODS

A two-round virtual internet-based Delphi process with 6 Danish pain specialists was undertaken. In the first round, questions were answered individually and anonymously, whereas in the second round, the panel openly discussed first round's summary of outcomes. Combinations of pharmacological pain treatments, that is, pregabalin/gabapentin, TCAs, serotonin-norepinephrine reuptake inhibitors (SNRIs), selective serotonin reuptake inhibitors, opioids, other antiepileptics and cutaneous patches, were assessed based on both scientific and clinical practice experiences. The Centers for Disease Control and Prevention (CDC) grading system was used for evidence rating.

RESULTS

Combination of pregabalin/gabapentin with TCA is useful in patients who do not gain sufficient pain relief or tolerate either drug in high doses, or to improve sleep disturbance. Also, combination of pregabalin/gabapentin and SNRIs is reasonably well documented and experienced by some experts to result in sufficient pain relief and fewer side effects than monotherapy. Good evidence on efficacy was found for the combination of pregabalin/gabapentin or TCAs and opioids, which was also frequently used in clinical practice. The evidence for combining TCAs and SNRIs is insufficient, although sometimes used in clinical practice despite the risk of serotonin syndrome. For localized NeP, combination therapy with cutaneous patches should be considered. There was insufficient scientific evidence for any pharmacologic combination therapies with selective serotonin reuptake inhibitors - as well as for other potential combinations.

CONCLUSIONS

The study revealed that combination therapy is widely used in clinical practice and supported by some scientific evidence. However, further studies are needed.

The Effect of Gabapentin and Tramadol in Cancer Pain Induced by Glioma Cell in Rat Femur

Preclinical Research The presence of pain as part of the cancer process is variable. Glioblastoma multiform (GBM) can produce bone metastasis, a condition that involves other pathological phenotypes including neuropathic and inflammatory pain. Tramadol and gabapentin are drugs used in the treatment of neuropathic pain. However, there are no studies evaluating their analgesic effects in bone metastasis. We produced a pain model induced by the inoculation of glioma cells (10⁵ ) into the rat femur, by perforating the intercodiloid fossa. Painful behavior was evaluated by measuring mechanical allodynia using the Von Frey test while thermal hyperalgesia was assessed in the plantar test. Histopathological features were evaluated and antinociceptive responses were compared using tramadol and gabapentin. The inoculation of cells inside the right femur produced nociceptive behaviors. Tramadol and gabapentin produced an anti-allodynic effect in this condition, but tramadol did not produce an anti-hyperalgesic response. The development of this model will allow us to perform tests to elucidate the pathology of bone metastasis, cancer pain, and in particular the pain produced by glioma. Drug Dev Res 78 : 173-183, 2017. © 2017 Wiley Periodicals, Inc.

Gabapentin for chronic neuropathic pain in adults

BACKGROUND

Gabapentin is commonly used to treat neuropathic pain (pain due to nerve damage). This review updates a review published in 2014, and previous reviews published in 2011, 2005 and 2000.

OBJECTIVES

To assess the analgesic efficacy and adverse effects of gabapentin in chronic neuropathic pain in adults.

SEARCH METHODS

For this update we searched CENTRAL), MEDLINE, and Embase for randomised controlled trials from January 2014 to January 2017. We also searched the reference lists of retrieved studies and reviews, and online clinical trials registries.

SELECTION CRITERIA

We included randomised, double-blind trials of two weeks' duration or longer, comparing gabapentin (any route of administration) with placebo or another active treatment for neuropathic pain, with participant-reported pain assessment.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed trial quality and potential bias. Primary outcomes were participants with substantial pain relief (at least 50% pain relief over baseline or very much improved on Patient Global Impression of Change scale (PGIC)), or moderate pain relief (at least 30% pain relief over baseline or much or very much improved on PGIC). We performed a pooled analysis for any substantial or moderate benefit. Where pooled analysis was possible, we used dichotomous data to calculate risk ratio (RR) and number needed to treat for an additional beneficial outcome (NNT) or harmful outcome (NNH). We assessed the quality of the evidence using GRADE and created 'Summary of findings' tables.

MAIN RESULTS

We included four new studies (530 participants), and excluded three previously included studies (126 participants). In all, 37 studies provided information on 5914 participants. Most studies used oral gabapentin or gabapentin encarbil at doses of 1200 mg or more daily in different neuropathic pain conditions, predominantly postherpetic neuralgia and painful diabetic neuropathy. Study duration was typically four to 12 weeks. Not all studies reported important outcomes of interest. High risk of bias occurred mainly due to small size (especially in cross-over studies), and handling of data after study withdrawal.In postherpetic neuralgia, more participants (32%) had substantial benefit (at least 50% pain relief or PGIC very much improved) with gabapentin at 1200 mg daily or greater than with placebo (17%) (RR 1.8 (95% CI 1.5 to 2.1); NNT 6.7 (5.4 to 8.7); 8 studies, 2260 participants, moderate-quality evidence). More participants (46%) had moderate benefit (at least 30% pain relief or PGIC much or very much improved) with gabapentin at 1200 mg daily or greater than with placebo (25%) (RR 1.8 (95% CI 1.6 to 2.0); NNT 4.8 (4.1 to 6.0); 8 studies, 2260 participants, moderate-quality evidence).In painful diabetic neuropathy, more participants (38%) had substantial benefit (at least 50% pain relief or PGIC very much improved) with gabapentin at 1200 mg daily or greater than with placebo (21%) (RR 1.9 (95% CI 1.5 to 2.3); NNT 5.9 (4.6 to 8.3); 6 studies, 1277 participants, moderate-quality evidence). More participants (52%) had moderate benefit (at least 30% pain relief or PGIC much or very much improved) with gabapentin at 1200 mg daily or greater than with placebo (37%) (RR 1.4 (95% CI 1.3 to 1.6); NNT 6.6 (4.9 to 9.9); 7 studies, 1439 participants, moderate-quality evidence).For all conditions combined, adverse event withdrawals were more common with gabapentin (11%) than with placebo (8.2%) (RR 1.4 (95% CI 1.1 to 1.7); NNH 30 (20 to 65); 22 studies, 4346 participants, high-quality evidence). Serious adverse events were no more common with gabapentin (3.2%) than with placebo (2.8%) (RR 1.2 (95% CI 0.8 to 1.7); 19 studies, 3948 participants, moderate-quality evidence); there were eight deaths (very low-quality evidence). Participants experiencing at least one adverse event were more common with gabapentin (63%) than with placebo (49%) (RR 1.3 (95% CI 1.2 to 1.4); NNH 7.5 (6.1 to 9.6); 18 studies, 4279 participants, moderate-quality evidence). Individual adverse events occurred significantly more often with gabapentin. Participants taking gabapentin experienced dizziness (19%), somnolence (14%), peripheral oedema (7%), and gait disturbance (14%).

AUTHORS' CONCLUSIONS

Gabapentin at doses of 1800 mg to 3600 mg daily (1200 mg to 3600 mg gabapentin encarbil) can provide good levels of pain relief to some people with postherpetic neuralgia and peripheral diabetic neuropathy. Evidence for other types of neuropathic pain is very limited. The outcome of at least 50% pain intensity reduction is regarded as a useful outcome of treatment by patients, and the achievement of this degree of pain relief is associated with important beneficial effects on sleep interference, fatigue, and depression, as well as quality of life, function, and work. Around 3 or 4 out of 10 participants achieved this degree of pain relief with gabapentin, compared with 1 or 2 out of 10 for placebo. Over half of those treated with gabapentin will not have worthwhile pain relief but may experience adverse events. Conclusions have not changed since the previous update of this review.

Prospective study of neuropathic pain after definitive surgery for extremity osteosarcoma in a pediatric population

BACKGROUND

Neuropathic pain (NP) after definitive surgery for extremity osteosarcoma (OS) has not been previously characterized. This study prospectively investigates the incidence, duration, and treatment of NP in limb sparing surgery and amputation groups.

PROCEDURE

In patients treated for OS on a chemotherapy and definitive surgery (limb sparing vs. amputation) protocol (OS08), we prospectively collected the following data: (i) demographical data (age, sex, race); (ii) NP time of onset and duration; and (iii) dose (starting, maximum) and duration of gabapentin, amitriptyline, and methadone treatment.

RESULTS

Thirty-seven patients underwent 38 definitive surgeries: limb sparing (26, 68.4%) or amputations (12, 31.6%). Localization included lower extremity (30, 81%), upper extremity (6, 16%), or pelvis (1, 3%). Thirty patients (81%) developed NP and 26 of them required NP-specific medications (87.7%). The mean [standard deviation (SD)] duration of NP was 6.5 weeks (7.2) (median 4.4, range 0.3-29.9). All 26 patients (27 surgeries) treated with NP medications received gabapentin, either as single therapy (65.4%) (17 patients, 18 surgeries), dual therapy with gabapentin and amitriptyline (five patients), or triple therapy with gabapentin, amitriptyline, and methadone (four patients). The mean starting (maximum) doses of gabapentin, amitriptyline, and methadone (mg/kg/day) were 20.2 (43.8), 0.5 (0.7), and 0.3 (0.3), respectively. The incidence and duration of NP, duration of treatment, and NP-specific dose regimens were similar in the limb sparing and the amputation groups.

CONCLUSIONS

NP after definitive surgery for OS is frequently encountered, can persist for a significant time, and NP outcomes are similar in limb sparing and amputation groups.

Impact of Hospital-Wide Comprehensive Pain Management Initiatives

This project aimed to improve pain management through clinician education, updated assessment tools, computer resources, and improved ordering and delivery systems. Clinicians were surveyed and results analyzed using Wilcoxon-Mann-Whitney testing and χ2 testing. Prescribing patterns were evaluated by comparing proportions of prescription orders and dose intervals. Cochran-Armitage Trend Test was used for linear trends in proportion of prescription orders over time. Knowledge scores improved significantly for nurses ( P = .004) and nurse practitioners/physician assistants ( P < .0001). Patient surveys showed a reduction in the percentage of patients dissatisfied with pain control. There was a decrease of 3.6% in intramuscular orders of opioids ( P < .0001). A significant reduction was found in the percentage of orders of potentially high initial doses of opioids of hydromorphone and morphine after implementing an electronic alert. This project demonstrates that a comprehensive educational strategy with improved assessment tools, clinical resources, and educational programming can have a significant impact on pain management.