Pregabalin, the lidocaine plaster and duloxetine in patients with refractory neuropathic pain: a systematic review

Effectiveness of Duloxetine versus Other Therapeutic Modalities in Patients with Diabetic Neuropathic Pain: A Systematic Review and Meta-Analysis

Objectives: Diabetic peripheral neuropathy (DPN) is a chronic complication of diabetes mellitus (DM) with symptoms like intense pain and impaired quality of life. This condition has no treatment; instead, the pain is managed with various antidepressants, including duloxetine. The aim of this study is to analyze the evidence on the efficacy of duloxetine in the management of DPN. Methods: A systematic search in different databases was conducted using the keywords "diabetic neuropathy", "duloxetine therapy", "neuropathic pain", and "Diabetes Mellitus". Finally, eight studies were included in this meta-analysis. Results: All articles comparing duloxetine at different doses vs. a placebo reported significant differences in favor of duloxetine on pain scales like 24 h Average Pain Severity (standardized mean difference [SMD] = -1.06, confidence interval [CI] = -1.09 to -1.03, and p < 0.00001) and BPI Severity (SMD = -0.70, CI = -0.72 to -0.68, and p < 0.00001), among others. A total of 75% of the meta-analyses of studies comparing duloxetine at different doses showed a tendency in favor of the 120 mg/d dose. There were significant differences in favor of duloxetine when compared to routine care on the Euro Quality of Life (SMD = -0.04, CI = -0.04 to -0.03, and p < 0.00001) and SF-36 Survey (SMD = -5.86, CI = -6.28 to -5.44, and p < 0.00001) scales. There were no significant differences on the visual analog scale (VAS) when comparing duloxetine and gabapentin. Conclusions: Duloxetine appears to be effective in the management of DPN in different pain, symptom improvement, and quality of life scales.

Therapeutic Approach for Trigeminal Neuralgia: A Systematic Review

This umbrella review aimed to determine the various drugs used to treat trigeminal neuralgia (TN) and to evaluate their efficacies as well as side effects by surveying previously published reviews. An online search was conducted using PubMed, CRD, EBSCO, Web of Science, Scopus, and the Cochrane Library with no limits on publication date or patients' gender, age, and ethnicity. Reviews and meta-analyses of randomized controlled trials pertaining to drug therapy for TN, and other relevant review articles added from their reference lists, were evaluated. Rapid reviews, reviews published in languages other than English, and reviews of laboratory studies, case reports, and series were excluded. A total of 588 articles were initially collected; 127 full-text articles were evaluated after removing the duplicates and screening the titles and abstracts, and 11 articles were finally included in this study. Except for carbamazepine, most of the drugs had been inadequately studied. Carbamazepine and oxcarbazepine continue to be the first choice for medication for classical TN. Lamotrigine and baclofen can be regarded as second-line drugs to treat patients not responding to first-line medication or for patients having intolerable side effects from carbamazepine. Drug combinations using carbamazepine, baclofen, gabapentin, ropivacaine, tizanidine, and pimozide can yield satisfactory results and improve the tolerance to the treatment. Intravenous lidocaine can be used to treat acute exaggerations and botulinum toxin-A can be used in refractory cases. Proparacaine, dextromethorphan, and tocainide were reported to be inappropriate for treating TN. Anticonvulsants are successful in managing trigeminal neuralgia; nevertheless, there have been few studies with high levels of proof, making it challenging to compare or even combine their results in a statistically useful way. New research on other drugs, combination therapies, and newer formulations, such as vixotrigine, is awaited. There is conclusive evidence for the efficacy of pharmacological drugs in the treatment of TN.

Management of Musculoskeletal Pain: An Update with Emphasis on Chronic Musculoskeletal Pain

Musculoskeletal pain is a challenging condition for both patients and physicians. Many adults have experienced one or more episodes of musculoskeletal pain at some time of their lives, regardless of age, gender, or economic status. It affects approximately 47% of the general population. Of those, about 39–45% have long-lasting problems that require medical consultation. Inadequately managed musculoskeletal pain can adversely affect quality of life and impose significant socioeconomic problems. This manuscript presents a comprehensive review of the management of chronic musculoskeletal pain. It briefly explores the background, classifications, patient assessments, and different tools for management according to the recently available evidence. Multimodal analgesia and multidisciplinary approaches are fundamental elements of effective management of musculoskeletal pain. Both pharmacological, non-pharmacological, as well as interventional pain therapy are important to enhance patient’s recovery, well-being, and improve quality of life. Accordingly, recent guidelines recommend the implementation of preventative strategies and physical tools first to minimize the use of medications. In patients who have had an inadequate response to pharmacotherapy, the proper use of interventional pain therapy and the other alternative techniques are vital for safe and effective management of chronic pain patients.

Systematic review and network meta-analysis of the efficacy and safety of lidocaine 700 mg medicated plaster vs. pregabalin

Objective: Neuropathic pain prevalence is estimated between 7% and 10% of the population. International guidelines recommend a variety of drugs at different therapy lines for pain relief. However, side effect profiles, for example, prompted the UK government recently to classify pregabalin and gabapentin as class C drugs. Lidocaine 700 mg medicated plaster (LMP) might be a safer alternative. A systematic review assessed how LMP and pregabalin compared in terms of efficacy and safety. The review focused on pain reduction, quality of life and adverse events in peripheral neuropathic pain (PNP) i.e. post-herpetic neuralgia, diabetic peripheral neuropathy, post-surgical/trauma, or other PNP conditions.Methods: Electronic databases were searched as well as a number of other sources up to November 2018. Sensitive strategies were used, with no restriction by language or publication status. Two independent reviewers screened records and extracted data with consensus determining final decisions. Risk of bias was assessed using the Cochrane Collaboration 2011 checklist for RCTs. Full network meta-analysis was conducted to compare LMP to pregabalin 300/600 mg in terms of pain reduction, quality of life, as well as serious adverse events and selected adverse events. Trials with enriched enrolment design were excluded.Results: Searches retrieved 7,104 records. In total 111 references pertaining to 43 RCTs were included for data extraction. Bayesian network meta-analysis of several pain outcomes showed no clear difference in efficacy between treatments However, LMP was clearly advantageous in terms of dizziness and any adverse event vs. pregabalin 600 mg/day and discontinuations vs. pregabalin 300 mg/day or 600 mg/day, as well as being associated with improved quality of life (albeit in this case based on weak evidence).Conclusions: LMP was found to be similar to pregabalin in reducing pain in all populations but had a better adverse events profile.

Trends in Medicalization of Children with Amplified Musculoskeletal Pain Syndrome

Objective

The objective of this survey was to describe trends over time in medicalization of children with Amplified Musculoskeletal Pain Syndrome (AMPS).

Design

A retrospective evaluation was conducted using self-reported data from patients presenting to the pain clinic between January 1, 2008 and December 31, 2014, who were diagnosed with AMPS.

Setting and Subjects

This was a medical record review of 899 subjects ages 3-20 presenting with Amplified Musculoskeletal Pain Syndrome. Subjects were included if they presented to a single tertiary specialized clinic and obtained a diagnosis of AMPS between January 1, 2008 and December 31, 2014.

Methods

Information collected from subjects' medical records included: past medications, current outpatient medications, procedures, aids, therapies, studies, professionals seen, hospitalizations, and surgeries. Trends in medicalization were analyzed by year of initial visit.

Results

Medication use, procedures, studies, therapies, professionals seen, hospitalizations, and surgeries in children with AMPS all increased significantly by year ( P  < 0.001). The degree of physical dysfunction, pain, and the use of aids did not significantly increase.

Conclusions

Children with amplified musculoskeletal pain syndrome are becoming increasingly medicalized. Increased medicalization introduces risk of iatrogenic injury and burdens families with unnecessary medical costs. The significant increase in medicalization of children with AMPS is not related to an increase in patient reported pain, which is evidenced by the lack of significant increase in patients' pain score, pain duration, or functional disability at the time of their initial evaluation.

Topical Treatment of Peripheral Neuropathic Pain: Applying the Evidence

CONTEXT

Patients with peripheral neuropathic pain (NP) may only achieve partial pain relief with currently recommended first-line oral treatments, which are also associated with systemic adverse events. Topical treatments are currently considered second- or third-line options, but a recent pharmacologic treatment algorithm has called for broader first-line use of these agents. This has highlighted a need to communicate the benefits associated with topical agents, in particular around the efficacy, targeted local action, and limited systemic availability resulting in minimal systemic adverse events and drug-drug interactions.

OBJECTIVES

This review aims to evaluate the evidence base for topical therapies currently used to treat peripheral NP, discuss the evidence comparing these treatments head-to-head with oral standard of care, and evaluate how they fit into treatment regimens in the "real world."

METHODS

This is a narrative review.

RESULTS

Two topical treatments are currently licensed: lidocaine 5% medicated plaster (post-herpetic neuralgia) and the capsaicin 8% patch (peripheral NP). When compared head to head with the oral standard of care (pregabalin), the lidocaine 5% medicated plaster provided similar relief of pain associated with post-herpetic neuralgia but did not meet the primary predefined criteria for noninferiority. The capsaicin 8% patch, however, demonstrated noninferior efficacy when compared head-to-head with pregabalin across a wide range of peripheral NP etiologies. Importantly, both treatments demonstrated effective pain relief without the systemic adverse events associated with oral therapies.

CONCLUSION

First-line use of topical agents may be of particular benefit in patients where the safety and tolerability of oral therapy is a concern.

Outcome measures in randomized-controlled trials of neuropathic pain conditions: a systematic review of systematic reviews and recommendations for practice

OBJECTIVES

Neuropathic pain (NeP) is a prevalent, disabling, multidimensional condition with significant morbidity; however, there appears to be a variable approach in the use of outcome measures in NeP trials. A search of systematic reviews of interventional randomized-controlled trials for NeP was undertaken to investigate the range and types of outcome measures used to determine treatment effects.

METHODS

Keywords and MESH searches were conducted in 5 electronic databases from inception to January 31, 2012. Full-text English-language reviews based on various acute and chronic NeP conditions were included. Two independent reviewers screened papers for inclusion, extracted data, and assessed the quality of reviews. Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines were used to critically appraise the reviews.

RESULTS

A total of 46 studies were identified: the majority of reviews (n=28/46, 61%) scored well on the PRISMA (PRISMA scores of 20-27/27). Change in levels or intensity of pain were used by the majority of studies as the primary outcome measure in intervention studies (n=40/46 studies, 87%). Few studies used a functional outcome measure as either a primary or secondary outcome measure (n=7/46, 15% of studies).

DISCUSSION

These results demonstrate that measures of pain are predominantly used in trials of NeP conditions and highlight the scant usage of functional outcome measures. The lack of standardization for the diagnostic criteria in NeP trials is also an issue that needs to be considered for future research and guideline development.

Add-on treatment with pregabalin for patients with uncontrolled neuropathic pain who have been referred to pain clinics

OBJECTIVE

The aim of this study was to investigate the impact of pregabalin on pain, other symptoms, and patient-reported outcomes for patients with uncontrolled pain who have been referred to pain clinics.

PATIENTS AND METHODS

Adult patients with uncontrolled pain who had a score of ≥4 in the DN4 questionnaire were evaluated at baseline, month 3, and month 6. Evaluations included pain levels using a visual analog (VAS) scale as well as anxiety, depression, sleep, disability, and treatment satisfaction employing validated tools.

RESULTS

Our sample comprised 413 patients who met the selection criteria, had not received pregabalin previously, and were prescribed pregabalin at the study initiation, mainly (97 %) as add-on therapy. Overall, patients had a statistically significant reduction in VAS pain score of 41 points (54 % reduction, p < 0.001), varying from 64 % reduction (oncological pain) to 31 % reduction (central neuropathic pain). Effect sizes for anxiety, depression, sleep, and treatment satisfaction improvement were moderate to large depending on the dimension and clinical entity.

CONCLUSION

Our results suggest that in patients with uncontrolled neuropathic pain of various origins who were treated at pain clinics, the addition of pregabalin to a wider pharmacological treatment regimen was associated with a clinically relevant improvement of pain and psychological well-being and a reduction in the impact of neuropathic pain on daily activities. Add-on treatment with pregabalin was well tolerated.

Effectiveness of pregabalin as monotherapy or combination therapy for neuropathic pain in patients unresponsive to previous treatments in a Spanish primary care setting

Background and Objective

Patients from a previous study of neuropathic pain (NP) in the Spanish primary care setting still had symptoms despite treatment. Subsequently, patients were treated as prescribed by their physician and followed up for 3 months. Since pregabalin has been shown to be effective in NP, including refractory cases, the objective of this study was to assess the effectiveness of pregabalin therapy in patients with NP refractory to previous treatments.

Methods

This was a post hoc analysis of pregabalin-naïve NP patients treated with pregabalin in a 3-month follow-up observational multicenter study to assess symptoms and satisfaction with treatment. Patients were evaluated with the Douleur Neuropathique en 4 questions (DN4), the Brief Pain Inventory (BPI) and the Treatment Satisfaction for Medication Questionnaire (SATMED-Q) overall satisfaction domain.

Results

1,670 patients (mean age 58 years, 59 % women), previously untreated or treated with ≥1 drug other than pregabalin, were treated with pregabalin (37 % on monotherapy). At 3 months, pain intensity and its interference with activities decreased by half (p < 0.0001), while the number of days with no or mild pain increased by a mean of 4.5 days (p < 0.0001). Treatment satisfaction increased twofold (p < 0.0001). Patients with a shorter history of pain and those with neuralgia and peripheral nerve compression syndrome (PCS) as etiologies had the highest proportion on monotherapy and showed the greatest improvements in pain-related parameters in their respective group categories.

Conclusion

Treatment with pregabalin (as monotherapy or combination therapy) provides benefits in pain and treatment satisfaction in patients with NP, including refractory cases. Shorter disease progression and neuralgia and PCS etiologies are favorable factors for pregabalin treatment response.

Antinociceptive effect of matrine on vincristine-induced neuropathic pain model in mice

Chemotherapy drugs treatment causes neuropathic pain, hyperalgesia and allodynia are common components of neuropathic pain, so effectively therapeutic strategy is required. In this study, we evaluated the antinociceptive effects of matrine on vincristine-induced neuropathic pain in mice. Vincristine (100 μg/kg i.p.) was administered once per day for 7 days (day 0-6) in mice. Matrine (15, 30, 60 mg/kg, i.p.) was repeated administration in early phase (day 0-6) or late phase (day 7-13). Hyperalgesia and allodynia were evaluated by withdrawal response using von Frey filaments, plantar and cold-plate on 7, 14 and 21 day. Injection of vincristine produced mechanical hyperalgesia and cold allodynia. Matrine was found to produce a protective role in both von Frey filaments and cold-plate test. The analysis of the effect supports the hypothesis that matrine is useful in therapy of vincristine-induced neuropathic pain. In conclusion, this study demonstrates that administration of matrine is associated with antinociceptive effect on mechanical and cold stimuli in a mice model of vincristine-induced neuropathy pain.

Interventions for treating pain and disability in adults with complex regional pain syndrome

BACKGROUND

There is currently no strong consensus regarding the optimal management of complex regional pain syndrome although a multitude of interventions have been described and are commonly used.

OBJECTIVES

To summarise the evidence from Cochrane and non-Cochrane systematic reviews of the effectiveness of any therapeutic intervention used to reduce pain, disability or both in adults with complex regional pain syndrome (CRPS).

METHODS

We identified Cochrane reviews and non-Cochrane reviews through a systematic search of the following databases: Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects (DARE), Ovid MEDLINE, Ovid EMBASE, CINAHL, LILACS and PEDro. We included non-Cochrane systematic reviews where they contained evidence not covered by identified Cochrane reviews. The methodological quality of reviews was assessed using the AMSTAR tool.We extracted data for the primary outcomes pain, disability and adverse events, and the secondary outcomes of quality of life, emotional well being and participants' ratings of satisfaction or improvement. Only evidence arising from randomised controlled trials was considered. We used the GRADE system to assess the quality of evidence.

MAIN RESULTS

We included six Cochrane reviews and 13 non-Cochrane systematic reviews. Cochrane reviews demonstrated better methodological quality than non-Cochrane reviews. Trials were typically small and the quality variable.There is moderate quality evidence that intravenous regional blockade with guanethidine is not effective in CRPS and that the procedure appears to be associated with the risk of significant adverse events.There is low quality evidence that bisphosphonates, calcitonin or a daily course of intravenous ketamine may be effective for pain when compared with placebo; graded motor imagery may be effective for pain and function when compared with usual care; and that mirror therapy may be effective for pain in post-stroke CRPS compared with a 'covered mirror' control. This evidence should be interpreted with caution. There is low quality evidence that local anaesthetic sympathetic blockade is not effective. Low quality evidence suggests that physiotherapy or occupational therapy are associated with small positive effects that are unlikely to be clinically important at one year follow up when compared with a social work passive attention control.For a wide range of other interventions, there is either no evidence or very low quality evidence available from which no conclusions should be drawn.

AUTHORS' CONCLUSIONS

There is a critical lack of high quality evidence for the effectiveness of most therapies for CRPS. Until further larger trials are undertaken, formulating an evidence-based approach to managing CRPS will remain difficult.

Interventions for treating pain and disability in adults with complex regional pain syndrome

BACKGROUND

There is currently no strong consensus regarding the optimal management of complex regional pain syndrome although a multitude of interventions have been described and are commonly used.

OBJECTIVES

To summarise the evidence from Cochrane and non-Cochrane systematic reviews of the effectiveness of any therapeutic intervention used to reduce pain, disability or both in adults with complex regional pain syndrome (CRPS).

METHODS

We identified Cochrane reviews and non-Cochrane reviews through a systematic search of the following databases: Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects (DARE), Ovid MEDLINE, Ovid EMBASE, CINAHL, LILACS and PEDro. We included non-Cochrane systematic reviews where they contained evidence not covered by identified Cochrane reviews. The methodological quality of reviews was assessed using the AMSTAR tool.We extracted data for the primary outcomes pain, disability and adverse events, and the secondary outcomes of quality of life, emotional well being and participants' ratings of satisfaction or improvement. Only evidence arising from randomised controlled trials was considered. We used the GRADE system to assess the quality of evidence.

MAIN RESULTS

We included six Cochrane reviews and 13 non-Cochrane systematic reviews. Cochrane reviews demonstrated better methodological quality than non-Cochrane reviews. Trials were typically small and the quality variable.There is moderate quality evidence that intravenous regional blockade with guanethidine is not effective in CRPS and that the procedure appears to be associated with the risk of significant adverse events.There is low quality evidence that bisphosphonates, calcitonin or a daily course of intravenous ketamine may be effective for pain when compared with placebo; graded motor imagery may be effective for pain and function when compared with usual care; and that mirror therapy may be effective for pain in post-stroke CRPS compared with a 'covered mirror' control. This evidence should be interpreted with caution. There is low quality evidence that local anaesthetic sympathetic blockade is not effective. Low quality evidence suggests that physiotherapy or occupational therapy are associated with small positive effects that are unlikely to be clinically important at one year follow up when compared with a social work passive attention control.For a wide range of other interventions, there is either no evidence or very low quality evidence available from which no conclusions should be drawn.

AUTHORS' CONCLUSIONS

There is a critical lack of high quality evidence for the effectiveness of most therapies for CRPS. Until further larger trials are undertaken, formulating an evidence-based approach to managing CRPS will remain difficult.