Experience and challenges presented by a multicenter crossover study of combination analgesic therapy for the treatment of painful HIV-associated polyneuropathies

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.

Combination Therapy for Neuropathic Pain: A Review of Recent Evidence

Pharmacological treatment is not very effective for neuropathic pain (NP). A progressive decrease in the estimated effect of NP drugs has been reported, giving rise to an increase in the use of the multimodal analgesic approach. We performed a new independent review to assess whether more and better-quality evidence has become available since the last systematic review. We evaluated the efficacy, tolerability, and safety of double-blinded randomized controlled trials involving only adult participants and comparing combination therapy (CT: ≥2 drugs) with a placebo and/or at least one other comparator with an NP indication. The primary outcome assessed was the proportion of participants reporting ≥50% pain reductions from baseline. The secondary outcome assessed was the proportion of drop-outs due to treatment-emergent adverse events. After removing duplicates, 2323 citations were screened, with 164 articles assessed for eligibility, from which 16 were included for qualitative analysis. From the latter, only five lasted for at least 12 weeks and only six complied with the required data for complete analysis. CT has been adopted for years without robust evidence. Efforts have been made to achieve better-quality evidence, but the quality has not improved over the years. In this regard, guidelines for NP should attempt to make recommendations about CT research, prioritizing which combinations to analyze.

Human immunodeficiency virus-related peripheral neuropathy: A systematic review and meta-analysis

BACKGROUND AND PURPOSE

Human immunodeficiency virus (HIV)-associated neurological syndromes occur in affected individuals as a consequence of primary HIV infection, opportunistic infections, inflammation and as an adverse effect of some forms of antiretroviral treatment (ART). The aim of this systematic review was to establish the epidemiological characteristics, clinical features, pathogenetic mechanisms and risk factors of HIV-related peripheral neuropathy (PN).

METHODS

A systematic, computer-based search was conducted using the PubMed database. Data regarding the above parameters were extracted. Ninety-four articles were included in this review.

RESULTS

The most commonly described clinical presentation of HIV neuropathy is the distal predominantly sensory polyneuropathy. The primary pathology in HIVPN appears to be axonal rather than demyelinating. Age and treatment with medications belonging in the nucleoside analogue reverse transcriptase class are risk factors for developing HIV-related neuropathy. The pooled prevalence of PN in patients naïve to ARTs was established to be 29% (95% CI: 9%-62%) and increased to 38% (95% confidence interval [CI]: 29%-48%) when looking into patients at various stages of their disease. More than half of patients with HIV-related neuropathy are symptomatic (53%, 95% CI: 41%-63%). Management of HIV-related neuropathy is mainly symptomatic, although there is evidence that discontinuation of some types of ART, such as didanosine, can improve or resolve symptoms.

CONCLUSIONS

Human immunodeficiency virus-related neuropathy is common and represents a significant burden in patients' lives. Our understanding of the disease has grown over the last years, but there are unexplored areas requiring further study.

Neuropathy complication of antiretroviral therapy in HIV/AIDS patients

OBJECTIVES

Significant pain from HIV-associated sensory neuropathy (HIV-SN) affects 40% of HIV-infected individuals treated with antiretroviral therapy (ART). The most salient symptom of the neuropathy is pain, which frequently is moderate-to-severe intensity, associated with reduced activities and physical function, sleep disruption, increased severity of depression, and anxiety. Yet, evidence for managing painful HIV-SN is poor. The purpose of this study was to verify by scientific evidence the neuropathy complication in HIV/AIDS patients to develop effective pain management strategies.

METHODS

Design: Systematic review.

DATA SOURCES

PubMed (MEDLINE), Cochrane, www.controlled-trials.com.

SELECTION CRITERIA

the filter "English" was used, timeframed searched was 2009-2019, randomized controlled trials (RCT). Keywords were verified in MeSH "Peripheral Nervous System Disease" and "Antiretroviral Agents" or "Antiretroviral therapy."

REVIEW METHOD

the PRISMA flowchart was used.

RESULT

A systematic search following PRISMA guidelines was carried out, and 12 specific articles/studies on the subject were selected. The results revealed that HIV therapy, aging, body mass index, height, and systemic conditions influence neuropathy conditions in HIV/AIDS patients. The multistudies focused on pain management approaches such as administration of pain medication, drug combination to prevent side effects, or ART with minimal side effects.

CONCLUSION

Sensory neuropathy is a frequent complication of HIV infection and ART. An understanding of the mechanism and pathophysiology of neuropathy in HIV is urgently required to develop alternative treatment modalities and to evaluate preventive strategies.

The Safety of Medications used to Treat Peripheral Neuropathic Pain, Part 2 (Opioids, Cannabinoids and Other Drugs): review of Double-Blind, Placebo-Controlled, Randomized Clinical Trials

INTRODUCTION

Peripheral neuropathic pain is a disabling condition for patients and a challenge for physicians. Although many drugs have been assessed in scientific studies, few have demonstrated clear clinical efficacy against neuropathic pain. Moreover, the paucity of data regarding their safety raises the question of the benefit-risk ratio when used in patients experiencing peripheral neuropathies.

AREAS COVERED

We conducted a review of double-blind, placebo-controlled, randomized clinical trials to assess the safety of medications used to treat peripheral neuropathic pain. This second review was focused on opioids, cannabinoids, and other medications. The aim was to provide an overview of the treatment-emergent adverse events (TEAEs) (≥10%) and the serious adverse effects described in clinical trials.

EXPERT OPINION

Opioids and cannabinoids had significantly more TEAEs than placebos. Locally administered analgesics, such as capsaicin, lidocaine, botulinum toxin A seemed to have the most acceptable safety with only local adverse effects. The results for NMDA antagonists were inconclusive since no safety report was available. Less than half of the studies included presented a good description of TEAEs that included a statistical comparison versus a placebo group. Major methodological improvements must be made to ameliorate the assessment of medication safety in future clinical trials.

Improving Study Conduct and Data Quality in Clinical Trials of Chronic Pain Treatments: IMMPACT Recommendations

The estimated probability of progressing from phase 3 analgesic clinical trials to regulatory approval is approximately 57%, suggesting that a considerable number of treatments with phase 2 trial results deemed sufficiently successful to progress to phase 3 do not yield positive phase 3 results. Deficiencies in the quality of clinical trial conduct could account for some of this failure. An Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials meeting was convened to identify potential areas for improvement in trial conduct in order to improve assay sensitivity (ie, ability of trials to detect a true treatment effect). We present recommendations based on presentations and discussions at the meeting, literature reviews, and iterative revisions of this article. The recommendations relate to the following areas: 1) study design (ie, to promote feasibility), 2) site selection and staff training, 3) participant selection and training, 4) treatment adherence, 5) data collection, and 6) data and study monitoring. Implementation of these recommendations may improve the quality of clinical trial data and thus the validity and assay sensitivity of clinical trials. Future research regarding the effects of these strategies will help identify the most efficient use of resources for conducting high quality clinical trials. PERSPECTIVE: Every effort should be made to optimize the quality of clinical trial data. This manuscript discusses considerations to improve conduct of pain clinical trials based on research in multiple medical fields and the expert consensus of pain researchers and stakeholders from academia, regulatory agencies, and industry.

Beyond pain: can antidepressants improve depressive symptoms and quality of life in patients with neuropathic pain? A systematic review and meta-analysis

Neuropathic pain can be a predictor of severe emotional distress, up to full-blown depressive states. In these patients, it is important to move beyond the sole treatment of pain, to recognize depressive symptoms, and to ultimately improve the quality of life. We systematically searched for published and unpublished clinical trials assessing the efficacy and tolerability of antidepressants vs placebo on depression, anxiety and quality of life in patients with neuropathic pain, and pooled data in a meta-analysis. A total of 37 studies fulfilled eligibility criteria and 32 provided data for meta-analysis. Antidepressants were more effective than placebo in improving depressive symptoms (standardized mean difference -0.11; 95% confidence interval -0.20 to -0.02), although the magnitude of effect was small, with a number needed to treat of 24. No significant difference emerged between antidepressants and placebo in reducing anxiety. Quality of life seemed improved in patients on antidepressants, as did pain. Acceptability and tolerability were higher in patients on placebo. To the best of our knowledge, this is the first meta-analysis specifically focusing on the effect of antidepressants on psychiatric symptoms and quality of life in patients with neuropathic pain. Our findings suggest that despite their potential benefit in patients with neuropathic pain, antidepressants should be prescribed with particular care because they might be less tolerable in such a fragile population. However, our findings warrant further research to explore how a correct use of antidepressants can help patients to cope with the consequences of neuropathic pain on their psychosocial health and quality of life.

Pharmacologic and Non-Pharmacologic Interventions for HIV-Neuropathy Pain. A Systematic Review and a Meta-Analysis

Background and Objectives: Among HIV infection symptoms, sensory neuropathy (HIV-SN) remains a main cause of suffering, with incidence varying from 13-50%. So far, numerous pharmacological and non-pharmacological treatments have been tested, although few evidence-based analgesic options are available. We conducted an up-to-date systematic review and meta-analysis of the literature in order to evaluate the efficacy and safety of pharmacologic and non-pharmacologic treatments for pain control, in patients with HIV neuropathy. Materials and Methods: We searched MEDLINE, EMBASE, Scopus/Elsevier, The Cochrane Central Register of Controlled Trials (CENTRAL), USA Clinical Trials registry, and The International Web of Science up to April 2019. All randomized controlled trials evaluating efficacy and safety of non-pharmacologic and pharmacologic therapies were included. Efficacy was defined as pain reduction during the study period. Safety was estimated from adverse events. A meta-analysis was performed whenever possible. Results: 27 randomized controlled trials (RCTs) were included for analysis (7 evaluating non pharmacologic interventions, 20 pharmacologic therapies). Non-pharmacologic studies (n = 742) involved seven different therapeutic modalities. Only Acupuncture/Moxibustion showed pain reduction over placebo, Gracely Pain Scale Mean (SD): Acu/Moxa 0.85 (0.12), placebo 1.10 (0.09), p = 0.05. Pharmacologic studies, involving 2516 patients revealed efficacy for capsaicin 8% over placebo (mean difference -8.04 [95% CI: -14.92 -1.15], smoked cannabis (where pooling data for meta-analysis was not possible) and recombinant Nerve Growth Factor. Conclusion: Despite various modalities for pain control in HIV-SN, strongest evidence exists for capsaicin 8% and smoked cannabis, although of low methodological quality. Among non-pharmacologic modalities, only Acu/Moxa gave a marginal beneficial effect in one study, possibly limited by inherent methodological flaws.

A Systematic Review of NMDA Receptor Antagonists for Treatment of Neuropathic Pain in Clinical Practice

OBJECTIVE

To investigate the efficacy of N-methyl-D-aspartate receptor (NMDAR) antagonists for neuropathic pain (NeuP) and review literature to determine if specific pharmacologic agents provide adequate NeuP relief.

METHODS

Literature was reviewed on PubMed using a variety of key words for 8 NMDAR antagonists. These key words include: "Ketamine and Neuropathy," "Ketamine and Neuropathic Pain," "Methadone and Neuropathy," "Methadone and Neuropathic Pain," "Memantine and Neuropathic pain," "Memantine and Neuropathy," "Amantadine and Neuropathic Pain," "Amantadine and Neuropathy," "Dextromethorphan and Neuropathic Pain," "Dextromethorphan and Neuropathy," "Carbamazepine and Neuropathic Pain," "Carbamazepine and Neuropathy," "Valproic Acid and Neuropathy," "Valproic Acid and Neuropathic Pain," "Phenytoin and Neuropathy," and "Phenytoin and Neuropathic Pain." With the results, the papers were reviewed using the PRISMA (Preferred Reporting in Systematic and Meta-Analyses) guideline.

RESULTS

A total of 58 randomized controlled trials were reviewed among 8 pharmacologic agents, which are organized by date and alphabetical order. Of the trials for ketamine, 15 showed some benefit for analgesia. Methadone had 3 positive trials, while amantadine and memantine each only had 2 trials showing NeuP analgesic properties. Dextromethorphan and valproic acid both had 4 randomized controlled trials that showed some NeuP treatment benefit while carbamazepine had over 8 trials showing efficacy. Finally, phenytoin only had 1 trial that showed clinical response in treatment.

CONCLUSIONS

There are a variety of NMDAR antagonist agents that should be considered for treatment of NeuP. Nevertheless, continued and further investigation of the 8 pharmacologic agents is needed to continue to evaluate their efficacy for treatment of NeuP.

2017 HIVMA of IDSA Clinical Practice Guideline for the Management of Chronic Pain in Patients Living With HIV

Pain has always been an important part of human immunodeficiency virus (HIV) disease and its experience for patients. In this guideline, we review the types of chronic pain commonly seen among persons living with HIV (PLWH) and review the limited evidence base for treatment of chronic noncancer pain in this population. We also review the management of chronic pain in special populations of PLWH, including persons with substance use and mental health disorders. Finally, a general review of possible pharmacokinetic interactions is included to assist the HIV clinician in the treatment of chronic pain in this population.It is important to realize that guidelines cannot always account for individual variation among patients. They are not intended to supplant physician judgment with respect to particular patients or special clinical situations. The Infectious Diseases Society of American considers adherence to these guidelines to be voluntary, with the ultimate determination regarding their application to be made by the physician in the light of each patient's individual circumstances.

Improved therapeutic potential of tapentadol employing cationic exchange resins as carriers in neuropathic pain: evidence from pharmacokinetic and pharmacodynamics study

Current investigation was endeavoured to overcome problem of poor palatability and bioavailability of centrally acting analgesic, tapentadol (TAP) by formulating controlled release drug-resin complexes (DRCs). The technology encompassed in preparation of DRCs involved chemisorption of TAP to weak cationic resins (KyronT-134 and Tulsion335) by batch method. Various formulation variables like drug-resin ratio, pH, resin activation and swelling time were optimized to achieve maximum drug loading in DRCs. FT-IR, DSC, pXRD, in vitro release study under bio-relevant condition of mouth and in vivo sensory taste evaluation established formation of taste masked DRC whereas dissolution study assured prolonged drug release behaviour of optimized DRC. Among DRCs, TAP-KyronT-134 complex exhibited higher drug loading (80.89 ± 4.56%), stability and prolonged release profile (10 h) without any detectable amount of drug release under salivary conditions. Pharmacokinetic studies in wistar rats revealed increased Tmax (2.67-fold), MRT (1.94-fold), elimination half-life (2.79-fold) and relative oral bioavailability (2.62-fold) of TAP on oral administration of optimized formulation compared to TAP solution. Furthermore, pharmacodynamics study confessed higher potential of DRC in attenuating chronic injury induced tactile allodynia for prolonged duration. In conclusion, the method developed is easily scalable and holds potential for commercialization with an evidence of obtaining more efficacious neuropathic pain management therapy.

Update of HIV-Associated Sensory Neuropathies

PURPOSE OF REVIEW

HIV-sensory neuropathy (HIV-SN) remains a common complication of HIV infection and may be associated with significant morbidity due to neuropathic pain. The overall purpose of this review is to discuss trends in the changing epidemiology in HIV-SN, new data regarding the pathophysiology of the condition, and discuss approaches to management.

RECENT FINDINGS

While HIV-SN has been historically considered the most common neurological complication of HIV infection, improved accessibility to effective combination antiretroviral therapy (cART), use of less neurotoxic antiretroviral medication regimens, and trends towards earlier introduction of treatment have impacted the condition: overall incident HIV-SN is likely decreased compared to prior rates and patients afflicted by HIV-SN may more frequently have asymptomatic or subclinical disease. Traditional predictors of HIV-SN have also changed, as traditional indices of severe immune deficiency such as low CD4 count and high viral load no longer predict HIV-SN. Emerging evidence supports the contention that both peripheral and central mechanisms underlying the generation as well as persistence of neuropathic pain in HIV-SN exist. It is important to recognize that even mild neuropathic pain in this clinical population is associated with meaningful impairment in quality of life and function, which emphasizes the clinical importance of recognizing and treating the condition. The general approach to management of neuropathic pain in HIV-SN is the introduction of symptomatic analgesic therapy. There exist, however, few evidence-based analgesic options for HIV-SN based on available clinical data. Symptomatic treatment trials are increasingly recognized to have been potentially confounded by more robust placebo response than that observed in other neuropathic pain conditions. In the authors' experience, use of analgesic therapies with proven efficacy in other neuropathic pain conditions is appropriate, bearing in consideration potential pharmacokinetic interactions with the cART regimen. Combination analgesic regimens may also achieve meaningful analgesic responses, particularly when drugs with differing mechanisms of action are utilized. It is paramount that the patient is appropriately counseled regarding expectations and the anticipated benefit of analgesic therapy, as pain relief is often incomplete but clinically meaningful improvement in pain and function can be achieved.

Participant Preferences for Pharmacologic Chronic Pain Treatment Trial Characteristics: An ACTTION Adaptive Choice-Based Conjoint Study

Barriers to clinical trial recruitment can delay study completion, potentially resulting in increased costs and an unrepresentative sample. In the current study of 150 participants with chronic pain, we used a computerized adaptive choice-based conjoint survey that included 8 characteristics that may affect enrollment in pharmacologic pain treatment trials (ie, treatment allocation, frequency of pain ratings, treatment administration method, current medications, number of study visits, availability of evening and weekend visits, invasiveness of laboratory procedures, payment). These data were analyzed using Sawtooth Software ver. 8.4.8 (Sawtooth Software, Inc, Orem, UT), which identifies the characteristics that dominate participants' decisions across multiple sets of potential trials. Three characteristics had the largest relative importance in participants' trial preferences: 1) invasiveness of required laboratory procedures (ie, 22%), with no procedures or blood tests preferred over ice-water sensory testing or skin biopsy; 2) ability to continue current pain medications (21%); and 3) payment for study participation (21%), with higher payment preferred. The fourth most important characteristic was number of study visits (13%), with participants preferring fewer in-person visits and more phone contacts. Understanding the preferences of potential participants is an important step toward enhancing enrollment in pain treatment trials.

PERSPECTIVE

This article presents the preferences of individuals with chronic pain conditions regarding modifiable pain treatment trial characteristics (eg, number of study visits, payment, treatment allocation). These findings may help to improve enrollment into analgesic clinical trials and in turn accelerate the development of new pain treatments.

Diagnosing and treating HIV-associated sensory neuropathy: a global perspective

HIV-associated sensory neuropathy (HIV-SN) is a common complication of HIV and remains highly prevalent even with modern HIV management strategies, causing debilitating pain in millions globally. We review HIV-SN diagnosis and management. We suggest most HIV-SN cases are easily recognized using clinical screening tools, with physician assessment and/or specialized testing prioritized for atypical cases. Management aims to prevent further nerve damage and optimize symptom control. Symptom relief is difficult and rarely complete, with a lack of proven pharmacological strategies. Work is needed to clarify optimal use of available medications. This includes understanding the marked placebo effect in HIV-SN analgesic trials and exploring 'responder phenotypes'. Limited data support nondrug strategies including hypnosis, meditation, psychology, physical activity and a positive therapeutic relationship.

Understanding the etiology and management of HIV-associated peripheral neuropathy

HIV may cause several forms of peripheral neuropathy, the most common of which is distal symmetric polyneuropathy (DSP) characterized by pain and sensory deficits in a stocking-glove distribution. The pathophysiology of DSP remains largely unknown but is thought to be related both to the neurotoxicity of HIV-through indirect immunomodulatory mechanisms-and to the neurotoxic effects of anti-retroviral therapies, most notably the dideoxynucleoside reverse transcription inhibitors or so-called d-drugs. Determining whether symptoms arise from the virus or the treatment poses a challenge to the clinician who must decide if a patient's HAART regimen should be altered. Treatment of symptoms related to HIV-DSP is a difficult task and there is no evidence that the traditional agents used in chronic neuropathic pain are efficacious in the HIV-DSP population. Indeed few pharmacologic agents have proven efficacy in HIV-DSP - these include cannabis and the capsaicin 8 % dermal patch. As such, alternative, non-pharmacologic therapies are being investigated. More research is needed to further elucidate the complex pathophysiology of HIV-DSP which may yield additional therapies for these patients.

Duloxetine for treating painful neuropathy, chronic pain or fibromyalgia

BACKGROUND

Duloxetine is a balanced serotonin and noradrenaline reuptake inhibitor licensed for the treatment of major depressive disorders, urinary stress incontinence and the management of neuropathic pain associated with diabetic peripheral neuropathy. A number of trials have been conducted to investigate the use of duloxetine in neuropathic and nociceptive painful conditions. This is the first update of a review first published in 2010.

OBJECTIVES

To assess the benefits and harms of duloxetine for treating painful neuropathy and different types of chronic pain.

SEARCH METHODS

On 19th November 2013, we searched The Cochrane Neuromuscular Group Specialized Register, CENTRAL, DARE, HTA, NHSEED, MEDLINE, and EMBASE. We searched ClinicalTrials.gov for ongoing trials in April 2013. We also searched the reference lists of identified publications for trials of duloxetine for the treatment of painful peripheral neuropathy or chronic pain.

SELECTION CRITERIA

We selected all randomised or quasi-randomised trials of any formulation of duloxetine, used for the treatment of painful peripheral neuropathy or chronic pain in adults.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by The Cochrane Collaboration.

MAIN RESULTS

We identified 18 trials, which included 6407 participants. We found 12 of these studies in the literature search for this update. Eight studies included a total of 2728 participants with painful diabetic neuropathy and six studies involved 2249 participants with fibromyalgia. Three studies included participants with depression and painful physical symptoms and one included participants with central neuropathic pain. Studies were mostly at low risk of bias, although significant drop outs, imputation methods and almost every study being performed or sponsored by the drug manufacturer add to the risk of bias in some domains. Duloxetine at 60 mg daily is effective in treating painful diabetic peripheral neuropathy in the short term, with a risk ratio (RR) for ≥ 50% pain reduction at 12 weeks of 1.73 (95% CI 1.44 to 2.08). The related NNTB is 5 (95% CI 4 to 7). Duloxetine at 60 mg daily is also effective for fibromyalgia over 12 weeks (RR for ≥ 50% reduction in pain 1.57, 95% CI 1.20 to 2.06; NNTB 8, 95% CI 4 to 21) and over 28 weeks (RR 1.58, 95% CI 1.10 to 2.27) as well as for painful physical symptoms in depression (RR 1.37, 95% CI 1.19 to 1.59; NNTB 8, 95% CI 5 to 14). There was no effect on central neuropathic pain in a single, small, high quality trial. In all conditions, adverse events were common in both treatment and placebo arms but more common in the treatment arm, with a dose-dependent effect. Most adverse effects were minor, but 16% of participants stopped the drug due to adverse effects. Serious adverse events were rare.

AUTHORS' CONCLUSIONS

There is adequate amounts of moderate quality evidence from eight studies performed by the manufacturers of duloxetine that doses of 60 mg and 120 mg daily are efficacious for treating pain in diabetic peripheral neuropathy but lower daily doses are not. Further trials are not required. In fibromyalgia, there is lower quality evidence that duloxetine is effective at similar doses to those used in diabetic peripheral neuropathy and with a similar magnitude of effect. The effect in fibromyalgia may be achieved through a greater improvement in mental symptoms than in somatic physical pain. There is low to moderate quality evidence that pain relief is also achieved in pain associated with depressive symptoms, but the NNTB of 8 in fibromyalgia and depression is not an indication of substantial efficacy. More trials (preferably independent investigator led studies) in these indications are required to reach an optimal information size to make convincing determinations of efficacy.Minor side effects are common and more common with duloxetine 60 mg and particularly with 120 mg daily, than 20 mg daily, but serious side effects are rare.Improved direct comparisons of duloxetine with other antidepressants and with other drugs, such as pregabalin, that have already been shown to be efficacious in neuropathic pain would be appropriate. Unbiased economic comparisons would further help decision making, but no high quality study includes economic data.