A comparative double-blind randomized study on the effectiveness of Duloxetine and Gabapentin on painful diabetic peripheral polyneuropathy

Rapid Onset of Pain Relief with Crisugabalin in Patients with Diabetic Peripheral Neuropathic Pain: Findings from a Multicenter, Randomized, Double-Blind, Controlled Study

INTRODUCTION

This study aims to evaluate the efficacy and safety of Crisugabalin in patients with diabetic peripheral neuropathic pain (DPNP), with a focus on its rapid onset of action.

METHODS

All the analyses in this study were based on data from a phase 2/3 adaptive randomized clinical trial that enrolled 596 patients. Participants were categorized into four treatment groups according to the intervention received: Crisugabalin 40 mg/day, Crisugabalin 80 mg/day, placebo, and Pregabalin 300 mg/day. The primary endpoint was the change in the average daily pain score (ADPS) over a 13-week treatment period. Secondary endpoints included changes in the Numeric Rating Scale (NRS) and the daily sleep interference score (DSIS) during the first two weeks of treatment.

RESULTS

Both Crisugabalin treatment groups (40 mg/day and 80 mg/day) demonstrated statistically significant reductions in ADPS compared to the placebo group starting from week 1 and continuing through week 13 (P < 0.05). Significant differences in pain relief for the Pregabalin group were observed only from week 6. Improvements in NRS and DSIS scores were also noted in both Crisugabalin groups, with statistically significant enhancements evident as early as day 2 of administration. Safety assessments indicated that Crisugabalin was well-tolerated, with a low incidence of serious adverse events and no significant increase in dropout rates among participants.

CONCLUSION

The findings suggest that Crisugabalin offers effective pain relief with an acceptable safety profile, highlighting its rapid onset in patients with DPNP.

CLINICAL TRIAL REGISTRATION

Clinical trial registration number derived from our parent project, we have retained the original registration identifier: NCT04647773.

Comparative analysis of the therapeutic effects of pregabalin, gabapentin, and duloxetine in diabetic peripheral neuropathy: A retrospective study

INTRODUCTION

This study aimed to compare the effects of pregabalin, gabapentin, and duloxetine on diabetic peripheral neuropathy (DPN) to guide tailored treatment.

MATERIALS AND METHODS

In this retrospective study, 180 patients with type 2 diabetes and DPN were matched 1:1:1 across three groups based on HbA1c and age, resulting in 60 patients per group. Clinical data were collected, and the painDETECT score was used to evaluate treatment response over six weeks.

RESULTS

After six weeks, the gabapentin group had significantly higher pain scores than the pregabalin (P = 0.002) and duloxetine groups (P < 0.001). The pregabalin group's scores were higher than the duloxetine group's, but not significantly (P = 0.62). Side effects were more frequent with duloxetine (23.3 %) compared to gabapentin (1.7 %) and pregabalin (6.7 %) (P = 0.001). Among those with over 50 % improvement, mean HbA1c levels were 9.42 for gabapentin, 10.43 for pregabalin, and 7.72 for duloxetine. Duloxetine significantly lowered HbA1c compared to gabapentin (P = 0.001) and pregabalin (P = 0.001), with no significant difference between gabapentin and pregabalin (P = 0.45).

CONCLUSION

Duloxetine and pregabalin effectively treat DPN. Gabapentin and pregabalin are suitable for patients with HbA1c over 8.7, while duloxetine is better for those with well-controlled HbA1c. Treatment should consider side effects, adherence, costs, and response time.

LEVEL OF THE EVIDENCE

Level III retrospective cohort study.

Neuropharmacology of Neuropathic Pain: A Systematic Review

Neuropathic pain, a debilitating condition, remains challenging to manage effectively. An insight into neuropharmacological mechanisms is critical for optimizing treatment strategies. This systematic review aims to evaluate the role of neuropharmacological agents based on their efficacy, involved neurotransmitters, and receptors. A manual literature search was undertaken in PubMed including Medline, Cochrane Library, Google Scholar, Plos One, Science Direct, and clinicaltrials.gov from 2013 until 2023. Out of the 13 included studies, seven evaluated the role of gabapentinoids. Two main drugs from this group, gabapentin and pregabalin, function by binding voltage-gated calcium channels, lowering neuronal hyperexcitability and pain signal transmission, thereby relieving neuropathic pain. Four of the pooled studies reported the use of tricyclic antidepressants (TCAs) including amitriptyline and nortriptyline which work by blocking the reuptake of norepinephrine and serotonin, their increased concentration is thought to be central to their analgesic effect. Three articles assessed the use of serotonin-norepinephrine reuptake inhibitors (SNRIs) and reported them as effective as the TCAs in managing neuropathic pain. They work by augmenting serotonin and norepinephrine. Three studies focused on the use of selective serotonin reuptake inhibitors (SSRIs), modulating their effect by increasing serotonin levels; however, they were reported as not a highly effective treatment option for neuropathic pain. One of the studies outlined the use of cannabinoids for neuropathic pain by binding to cannabinoid receptors with only mild adverse effects. It is concluded that gabapentinoids, TCAs, and SNRIs were reported as the most effective therapy for neuropathic pain; however, for trigeminal neuralgia, anticonvulsants like carbamazepine were considered the most effective. Opioids were considered second-line drugs for neuropathic pain as they come with adverse effects and a risk of dependence. Ongoing research is exploring novel drugs like ion channels and agents modulating pain pathways for neuropathic pain management. Our review hopes to inspire further research into patient stratification by their physiology, aiding quicker and more accurate management of neuropathic pain while minimizing inadvertent side effects.

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.

PPARγ and AKt gene modulation following pregabalin and duloxetine combination for painful diabetic polyneuropathy

Aim: Diabetic peripheral neuropathy (DPN) induces chronic neuropathic pain in diabetic patients. Current treatments like pregabalin and duloxetine offer limited efficacy. This study evaluates combining pregabalin and duloxetine versus pregabalin alone for DPN pain relief, and explores gene modulation (PPARγ and Akt) to understand neuropathic pain's molecular basis.Materials & methods: Diabetic patients with DPN were randomized into groups receiving combination therapy or pregabalin alone for 4 weeks. Pain intensity, gene expression and quality of life were assessed.Results: Combination therapy significantly reduced pain, improved quality of life and upregulated PPARγ and Akt genes compared with monotherapy.Conclusion: Pregabalin and duloxetine combination therapy in DPN led to PPARγ mRNA upregulation and negative correlation of Akt gene expression with pain scores. This combination therapy effectively reduced pain and improved quality of life.Clinical Trial Registration: CTRI/2021/02/031068.

Evaluation of Effectiveness and Safety of Firstline Drugs Used in the Treatment of Peripheral Neuropathy Among Elderly Population-A Randomised, Open-label, Active Comparator Study

Background

Peripheral neuropathy is four times more common in geriatric age group patients compared to younger ones. Most of the trials have targeted adult population, and there is scarcity of data in the geriatric age group.

Purpose

A real-world study was planned on geriatric patients suffering from peripheral neuropathy to analyse the effectiveness and safety of first-line drugs used in the management of peripheral neuropathy.

Methods

It was a randomised, open-label, active comparator clinical trial in which first-line drugs for peripheral neuropathy were compared [amitriptyline (10 mg), duloxetine (30 mg), gabapentin (300 mg), pregabalin (75 mg)] for their effectiveness and safety. The trial duration was eight weeks. The modified Toronto Clinical Neuropathy Score (mTCNS), Verbal Rating Scale (VRS) and Geriatric Depression Scale (GDS) were used for effectiveness. Safety was assessed by monitoring adverse events. Multiple groups were compared with Kruskal-Wallis test, and post hoc analysis was performed with Dunn's test. A p value <.05 was considered significant.

Results

A total of 80 patients were recruited (20 patients in each arm) with a mean age of 65.4 years, and 56.3% were male. Pregabalin was superior to amitriptyline (p = .04) and duloxetine (p = .02) in reducing mTCNS. Similarly, pregabalin was superior to amitriptyline (p = .041 and duloxetine (p = .009) in reducing GDS score. All drugs were comparable in reducing VRS (p = .17). A total of 14 adverse events were observed, out of which constipation, sedation and dizziness were common. Maximum adverse events were observed in the duloxetine arm (6/14).

Conclusion

Pregabalin was superior to amitriptyline and duloxetine, whereas it was comparable to gabapentin in effectiveness. Constipation was the most common adverse event, but the central nervous system was the most involved in adverse events.

A systematic review and meta-analysis of randomized controlled head-to-head trials of recommended drugs for neuropathic pain

Neuropathic pain is a challenging chronic pain condition. Limited knowledge exists regarding the relative effectiveness of pharmacological treatments, and differences in trial design and impact of the placebo response preclude indirect comparisons of efficacy between drug classes. The purpose of this systematic review and meta-analysis of head-to-head trials was to compare the efficacy and tolerability of drugs recommended for neuropathic pain. We conducted a systematic review and meta-analysis of direct-comparison double-blind randomized trials. Primary outcomes were mean change in pain intensity and number of responders with a 50% reduction in pain intensity. Secondary outcomes encompassed quality of life, sleep, emotional functioning, and number of dropouts because of adverse events. We included 30 trials (4087 patients), comprising 16 crossover and 14 parallel-group design studies. All studies were conducted in adults, and the majority were investigator-initiated trials. We found moderate-quality evidence for equivalence (no clinically relevant difference) between tricyclic antidepressants (TCA) and gabapentin/pregabalin with a combined mean difference in pain score of 0.10 (95% CI -0.13 to 0.32). We could not document differences between TCA and serotonin-noradrenaline reuptake inhibitors (SNRI), between SNRI and gabapentin/pregabalin, or between opioids and TCA (low quality of evidence). We found more dropouts because of adverse events with SNRI and opioids compared with TCA (low quality of evidence). We did not identify any studies that included topical treatments. This systematic review of direct-comparison studies found evidence for equivalence between TCA and gabapentin/pregabalin and fewer dropouts with TCA than SNRI and opioids.

Topical Nigella sativa L. product: a new candidate for the management of diabetic peripheral neuropathy

BACKGROUND

Diabetic neuropathy is one of the most common complications of diabetes. The synthetic drugs available in the market have side effects and limitations for diabetic patients, the vast majority of whom are in the upper age group. In this regard, based on Persian medicinal sources, Nigella sativa (N. sativa) has proved to have beneficial effects on neuropathic pain and neurological disorders. In this study, the effect of N. sativa is investigated topically in patients with diabetic neuropathy.

METHODS

This study was performed as a double-blind clinical trial on 120 neuropathic patients. The patients were divided into three groups. The first group received a topical N. sativa product as an ointment, the second group was given a topical placebo, and the third received 300 mg gabapentin capsules. The blindness was done in first and second groups. Diabetic neuropathy was assessed before the study using the Michigan Neuropathy Screening Instrument (MNSI). In addition, neuropathy symptoms were evaluated after the trial using the MNSI questionnaire.

RESULTS

The data were elicited from the patients' answers to a number of questions in the Michigan questionnaire. There were statistically significant differences between the group that received the topical N. sativa product and the other two groups in terms of legs and feet numbness (p value = 0.001), burning pain in feet or legs (p value = 0.001), muscle cramps in feet or legs (p value = 0.001), prickling fleeing in feet or legs (p value = 0.001), hurting of the skin when the bed covers touch it (p value = 0.005), aggravated symptoms at night (p value = 0.001) and hurting feelings in the legs when walking (p value = 0.032). However, the three studied groups were not statistically different in distinguishing hot water from cold water.

CONCLUSION

According to the results of this study, the topical use of N. sativa, compared to the current drugs, has acceptable improving effects on diabetic neuropathic patients.

Effectiveness of oral clonidine and gabapentin on peripheral neuropathy in diabetic patients in southwestern Iran: a randomized clinical trial

BACKGROUND

Peripheral neuropathy is not only the most prevalent consequence of diabetes but also the main reason for foot ulceration, disability, and amputation. Therefore, the current study aims to determine the effectiveness of oral clonidine and gabapentin on peripheral neuropathy in diabetic patients.

METHODS

This 12-week, randomized, and parallel-group trial was conducted to compare the efficacy of oral clonidine and gabapentin with gabapentin alone in diabetic patients in southwest Iran during the first half of 2021. Thirty patients with type 2 diabetes with peripheral neuropathy as assessed by a visual analog scale (VAS) and divided into two groups of 15 patients, treated for up to three months. The data were analyzed using SPSS-21 software. In order to report the results, descriptive indices, independent t-test, one-way analysis of covariance (ANCOVA) and analysis of variance with repeated measures were used.

RESULTS

The mean and standard deviation of the age of the participants in the clonidine + gabapentin group was equal to 50.20 ± 7.44, and in the gabapentin group was equal to 50.47 ± 7.57 (t = 0.10, P-value = 0.923). This research showed a significant difference between the clonidine + gabapentin group and with gabapentin group in terms of neuropathic pain and the severity of neuropathic pain (P < 0.001).

CONCLUSIONS

According to this research results, clonidine + gabapentin can reduce neuropathic pain and the severity of neuropathic pain in diabetic patients. Therefore, it is recommended that healthcare professionals with diabetes expertise prescribe these medications to reduce neuropathic pain and its severity.

TRIAL REGISTRATION

This study was registered in the Iranian Clinical Trials System with the ID (IRCT20211106052983N1) on 14/01/2022.

Antidepressants for pain management in adults with chronic pain: a network meta-analysis

BACKGROUND

Chronic pain is common in adults, and often has a detrimental impact upon physical ability, well-being, and quality of life. Previous reviews have shown that certain antidepressants may be effective in reducing pain with some benefit in improving patients' global impression of change for certain chronic pain conditions. However, there has not been a network meta-analysis (NMA) examining all antidepressants across all chronic pain conditions.

OBJECTIVES

To assess the comparative efficacy and safety of antidepressants for adults with chronic pain (except headache).

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, CINAHL, LILACS, AMED and PsycINFO databases, and clinical trials registries, for randomised controlled trials (RCTs) of antidepressants for chronic pain conditions in January 2022.

SELECTION CRITERIA

We included RCTs that examined antidepressants for chronic pain against any comparator. If the comparator was placebo, another medication, another antidepressant, or the same antidepressant at different doses, then we required the study to be double-blind. We included RCTs with active comparators that were unable to be double-blinded (e.g. psychotherapy) but rated them as high risk of bias. We excluded RCTs where the follow-up was less than two weeks and those with fewer than 10 participants in each arm.  DATA COLLECTION AND ANALYSIS: Two review authors separately screened, data extracted, and judged risk of bias. We synthesised the data using Bayesian NMA and pairwise meta-analyses for each outcome and ranked the antidepressants in terms of their effectiveness using the surface under the cumulative ranking curve (SUCRA). We primarily used Confidence in Meta-Analysis (CINeMA) and Risk of Bias due to Missing Evidence in Network meta-analysis (ROB-MEN) to assess the certainty of the evidence. Where it was not possible to use CINeMA and ROB-MEN due to the complexity of the networks, we used GRADE to assess the certainty of the evidence. Our primary outcomes were substantial (50%) pain relief, pain intensity, mood, and adverse events. Our secondary outcomes were moderate pain relief (30%), physical function, sleep, quality of life, Patient Global Impression of Change (PGIC), serious adverse events, and withdrawal.

MAIN RESULTS

This review and NMA included 176 studies with a total of 28,664 participants. The majority of studies were placebo-controlled (83), and parallel-armed (141). The most common pain conditions examined were fibromyalgia (59 studies); neuropathic pain (49 studies) and musculoskeletal pain (40 studies). The average length of RCTs was 10 weeks. Seven studies provided no useable data and were omitted from the NMA. The majority of studies measured short-term outcomes only and excluded people with low mood and other mental health conditions. Across efficacy outcomes, duloxetine was consistently the highest-ranked antidepressant with moderate- to high-certainty evidence. In duloxetine studies, standard dose was equally efficacious as high dose for the majority of outcomes. Milnacipran was often ranked as the next most efficacious antidepressant, although the certainty of evidence was lower than that of duloxetine. There was insufficient evidence to draw robust conclusions for the efficacy and safety of any other antidepressant for chronic pain.  Primary efficacy outcomes Duloxetine standard dose (60 mg) showed a small to moderate effect for substantial pain relief (odds ratio (OR) 1.91, 95% confidence interval (CI) 1.69 to 2.17; 16 studies, 4490 participants; moderate-certainty evidence) and continuous pain intensity (standardised mean difference (SMD) -0.31, 95% CI -0.39 to -0.24; 18 studies, 4959 participants; moderate-certainty evidence). For pain intensity, milnacipran standard dose (100 mg) also showed a small effect (SMD -0.22, 95% CI -0.39 to 0.06; 4 studies, 1866 participants; moderate-certainty evidence). Mirtazapine (30 mg) had a moderate effect on mood (SMD -0.5, 95% CI -0.78 to -0.22; 1 study, 406 participants; low-certainty evidence), while duloxetine showed a small effect (SMD -0.16, 95% CI -0.22 to -0.1; 26 studies, 7952 participants; moderate-certainty evidence); however it is important to note that most studies excluded participants with mental health conditions, and so average anxiety and depression scores tended to be in the 'normal' or 'subclinical' ranges at baseline already. Secondary efficacy outcomes Across all secondary efficacy outcomes (moderate pain relief, physical function, sleep, quality of life, and PGIC), duloxetine and milnacipran were the highest-ranked antidepressants with moderate-certainty evidence, although effects were small. For both duloxetine and milnacipran, standard doses were as efficacious as high doses. Safety There was very low-certainty evidence for all safety outcomes (adverse events, serious adverse events, and withdrawal) across all antidepressants. We cannot draw any reliable conclusions from the NMAs for these outcomes.

AUTHORS' CONCLUSIONS

Our review and NMAs show that despite studies investigating 25 different antidepressants, the only antidepressant we are certain about for the treatment of chronic pain is duloxetine. Duloxetine was moderately efficacious across all outcomes at standard dose. There is also promising evidence for milnacipran, although further high-quality research is needed to be confident in these conclusions. Evidence for all other antidepressants was low certainty. As RCTs excluded people with low mood, we were unable to establish the effects of antidepressants for people with chronic pain and depression. There is currently no reliable evidence for the long-term efficacy of any antidepressant, and no reliable evidence for the safety of antidepressants for chronic pain at any time point.

Glutamatergic systems in neuropathic pain and emerging non-opioid therapies

Neuropathic pain, a disease of the somatosensory nervous system, afflicts many individuals and adequate management with current pharmacotherapies remains elusive. The glutamatergic system of neurons, receptors and transporters are intimately involved in pain but, to date, there have been few drugs developed that therapeutically modulate this system. Glutamate transporters, or excitatory amino acid transporters (EAATs), remove excess glutamate around pain transmitting neurons to decrease nociception suggesting that the modulation of glutamate transporters may represent a novel approach to the treatment of pain. This review highlights and summarizes (1) the physiology of the glutamatergic system in neuropathic pain, (2) the preclinical evidence for dysregulation of glutamate transport in animal pain models, and (3) emerging novel therapies that modulate glutamate transporters. Successful drug discovery requires continuous focus on basic and translational methods to fully elucidate the etiologies of this disease to enable the development of targeted therapies. Increasing the efficacy of astrocytic EAATs may serve as a new way to successfully treat those suffering from this devastating disease.

American Association of Clinical Endocrinology Clinical Practice Guideline: Developing a Diabetes Mellitus Comprehensive Care Plan-2022 Update

OBJECTIVE

The objective of this clinical practice guideline is to provide updated and new evidence-based recommendations for the comprehensive care of persons with diabetes mellitus to clinicians, diabetes-care teams, other health care professionals and stakeholders, and individuals with diabetes and their caregivers.

METHODS

The American Association of Clinical Endocrinology selected a task force of medical experts and staff who updated and assessed clinical questions and recommendations from the prior 2015 version of this guideline and conducted literature searches for relevant scientific papers published from January 1, 2015, through May 15, 2022. Selected studies from results of literature searches composed the evidence base to update 2015 recommendations as well as to develop new recommendations based on review of clinical evidence, current practice, expertise, and consensus, according to established American Association of Clinical Endocrinology protocol for guideline development.

RESULTS

This guideline includes 170 updated and new evidence-based clinical practice recommendations for the comprehensive care of persons with diabetes. Recommendations are divided into four sections: (1) screening, diagnosis, glycemic targets, and glycemic monitoring; (2) comorbidities and complications, including obesity and management with lifestyle, nutrition, and bariatric surgery, hypertension, dyslipidemia, retinopathy, neuropathy, diabetic kidney disease, and cardiovascular disease; (3) management of prediabetes, type 2 diabetes with antihyperglycemic pharmacotherapy and glycemic targets, type 1 diabetes with insulin therapy, hypoglycemia, hospitalized persons, and women with diabetes in pregnancy; (4) education and new topics regarding diabetes and infertility, nutritional supplements, secondary diabetes, social determinants of health, and virtual care, as well as updated recommendations on cancer risk, nonpharmacologic components of pediatric care plans, depression, education and team approach, occupational risk, role of sleep medicine, and vaccinations in persons with diabetes.

CONCLUSIONS

This updated clinical practice guideline provides evidence-based recommendations to assist with person-centered, team-based clinical decision-making to improve the care of persons with diabetes mellitus.

Prevention and Management Strategies for Diabetic Neuropathy

Diabetic neuropathy (DN) is a common complication of diabetes that is becoming an increasing concern as the prevalence of diabetes rapidly rises. There are several types of DN, but the most prevalent and studied type is distal symmetrical polyneuropathy, which is the focus of this review and is simply referred to as DN. It can lead to a wide range of sensorimotor and psychosocial symptoms and is a major risk factor for diabetic foot ulceration and Charcot neuropathic osteoarthropathy, which are associated with high rates of lower limb amputation and mortality. The prevention and management of DN are thus critical, and clinical guidelines recommend several strategies for these based on the best available evidence. This article aims to provide a narrative review of DN prevention and management strategies by discussing these guidelines and the evidence that supports them. First, the epidemiology and diverse clinical manifestations of DN are summarized. Then, prevention strategies such as glycemic control, lifestyle modifications and footcare are discussed, as well as the importance of early diagnosis. Finally, neuropathic pain management strategies and promising novel therapies under investigation such as neuromodulation devices and nutraceuticals are reviewed.

Comparison of the Efficacy and Safety of Duloxetine and Gabapentin in Diabetic Peripheral Neuropathic Pain: A Meta-Analysis

Background

Diabetic peripheral neuropathic pain (DPNP) is a common chronic pain condition affecting diabetic patients and has growing importance because of the increasing prevalence of patients with type 2 diabetes mellitus. Pain is the most troublesome symptom of DPNP, increasingly recognized as an important and independent feature of DPNP. This meta-analysis aims to compare the efficacy and safety of duloxetine and gabapentin in the treatment of diabetic peripheral neuropathic pain (DPNP) and therefore to provide evidence-based medicine for clinical treatment.

Methods

Relevant randomized controlled trials on duloxetine versus gabapentin for DPNP were searched from PubMed, Embase, Cochrane Library, Web of Science, CNKI, WanFang, VIP, and Chinese Biomedical Literature Database from database inception to October 2021. The data were analyzed by RevMan 5.3 software.

Results

Seven studies were included. The results showed that, at the end of the study, duloxetine was significantly superior to gabapentin in terms of the incidence of adverse reactions (RR = 0.59, 95% CI: 0.45–0.79, P < 0.01), sleep interference score (SMD = −0.35, 95% CI: −0.63 to −0.08, P < 0.05), but no significant differences in VAS score (SMD = −0.14, 95% CI: −0.31–0.03, P > 0.05), overall response rate (RR = 1.05, 95% CI: 0.92–1.20, P > 0.05), and clinical global impression of change (SMD = 0.07, 95% CI: −0.20–0.35, P > 0.05).

Conclusion

Compared with gabapentin, duloxetine has no obvious advantage in the treatment of diabetic peripheral neuralgia, but it has less side effects and significantly higher safety.

Neuromodulation Interventions for the Treatment of Painful Diabetic Neuropathy: a Systematic Review

PURPOSE OF REVIEW

Painful diabetic neuropathy (PDN) is a prevalent and debilitating condition, characterized by severe burning, tingling, and lancinating pain usually located in the distal lower extremities. In addition to manifesting with severe pain, PDN may also be associated with poor quality of life and sleep, mood disorders, burns, falls, and social withdrawal. The authors appraised the current body of literature for evidence on neuromodulation interventions for PDN.

RECENT FINDINGS

In patients with refractory PDN unresponsive to conventional medical management (glucose optimization and oral analgesic medications), there is level I evidence supporting the use of 10-kHz and tonic dorsal column spinal cord stimulation (SCS). Included studies reported significant associations between 10-kHz and tonic dorsal column SCS and superior analgesic outcomes, physical functioning, and patient satisfaction. Current level of evidence remains limited for other modalities of neuromodulation for PDN including burst SCS (level II-3), dorsal root ganglion SCS (level III), and peripheral nerve stimulation (level II-3). Some studies reported improvements in neurological physical examination, sensory testing, and/or reflex testing in patients undergoing 10-kHz SCS for treatment of PDN. In summary, the purpose of this review is to equip provider with important updates on the use of neuromodulation interventions for the treatment of PDN that is refractory to conventional medical therapy, with current level I evidence supporting use of 10-kHz and tonic SCS for PDN.

An Insight into Potential Pharmacotherapeutic Agents for Painful Diabetic Neuropathy

Diabetes is the 4th most common disease affecting the world's population. It is accompanied by many complications that deteriorate the quality of life. Painful diabetic neuropathy (PDN) is one of the debilitating consequences of diabetes that effects one-third of diabetic patients. Unfortunately, there is no internationally recommended drug that directly hinders the pathological mechanisms that result in painful diabetic neuropathy. Clinical studies have shown that anticonvulsant and antidepressant therapies have proven fruitful in management of pain associated with PDN. Currently, the FDA approved medications for painful diabetic neuropathies include duloxetine, pregabalin, tapentadol extended release, and capsaicin (for foot PDN only). The FDA has also approved the use of spinal cord stimulation system for the treatment of diabetic neuropathy pain. The drugs recommended by other regulatory bodies include gabapentin, amitriptyline, dextromethorphan, tramadol, venlafaxine, sodium valproate, and 5 % lidocaine patch. These drugs are only partially effective and have adverse effects associated with their use. Treating painful symptoms in diabetic patient can be frustrating not only for the patients but also for health care workers, so additional clinical trials for novel and conventional treatments are required to devise more effective treatment for PDN with minimal side effects. This review gives an insight on the pathways involved in the pathogenesis of PDN and the potential pharmacotherapeutic agents. This will be followed by an overview on the FDA-approved drugs for PDN and commercially available topical analgesic and their effects on painful diabetic neuropathies.

The Treatment of Painful Diabetic Neuropathy

Painful diabetic peripheral neuropathy (painful-DPN) is a highly prevalent and disabling condition, affecting up to one-third of patients with diabetes. This condition can have a profound impact resulting in a poor quality of life, disruption of employment, impaired sleep, and poor mental health with an excess of depression and anxiety. The management of painful-DPN poses a great challenge. Unfortunately, currently there are no Food and Drug Administration (USA) approved disease-modifying treatments for diabetic peripheral neuropathy (DPN) as trials of putative pathogenetic treatments have failed at phase 3 clinical trial stage. Therefore, the focus of managing painful- DPN other than improving glycaemic control and cardiovascular risk factor modification is treating symptoms. The recommended treatments based on expert international consensus for painful- DPN have remained essentially unchanged for the last decade. Both the serotonin re-uptake inhibitor (SNRI) duloxetine and α2δ ligand pregabalin have the most robust evidence for treating painful-DPN. The weak opioids (e.g. tapentadol and tramadol, both of which have an SNRI effect), tricyclic antidepressants such as amitriptyline and α2δ ligand gabapentin are also widely recommended and prescribed agents. Opioids (except tramadol and tapentadol), should be prescribed with caution in view of the lack of definitive data surrounding efficacy, concerns surrounding addiction and adverse events. Recently, emerging therapies have gained local licenses, including the α2δ ligand mirogabalin (Japan) and the high dose 8% capsaicin patch (FDA and Europe). The management of refractory painful-DPN is difficult; specialist pain services may offer off-label therapies (e.g. botulinum toxin, intravenous lidocaine and spinal cord stimulation), although there is limited clinical trial evidence supporting their use. Additionally, despite combination therapy being commonly used clinically, there is little evidence supporting this practise. There is a need for further clinical trials to assess novel therapeutic agents, optimal combination therapy and existing agents to determine which are the most effective for the treatment of painful-DPN. This article reviews the evidence for the treatment of painful-DPN, including emerging treatment strategies such as novel compounds and stratification of patients according to individual characteristics (e.g. pain phenotype, neuroimaging and genotype) to improve treatment responses.

Comparison of efficacy and safety of gabapentin and duloxetine in painful diabetic peripheral neuropathy: A systematic review and meta-analysis of randomised controlled trials

BACKGROUND

In patients with diabetes mellitus, painful diabetic peripheral neuropathy (PDPN) is a frequent complication and can cause poor quality of life. We compared the efficacy and safety of duloxetine with those of gabapentin in patients with PDPN through a systematic review and meta-analysis of randomised controlled trials.

MATERIALS AND METHODS

PubMed, Embase and the Cochrane Library were searched for eligible studies published from database inception to January 2021. Visual Analogue Scale (VAS), sleep interference score, Clinical Global Impression of Change (CGIC), Patient Global Impression of Change (PGIC), Diabetic Neuropathy Symptom (DNS) score, Diabetic Neuropathic Examination (DNE) score, Neuropathic Disability Score (NDS) and side effects were used to compare duloxetine and gabapentin in patients with PDPN.

RESULTS

Three eligible randomised controlled trials involving 290 patients were included. No significant differences were observed between patients receiving duloxetine and gabapentin with respect to VAS (mean change difference = -1.23, 95% CI, -6.09 to 3.62; P = .62), sleep interference score (mean change difference = 0.42, 95% CI, -0.15 to 1.00; P = .15), CGIC (mean difference = 0.04, 95% CI, -0.11 to 0.20; P = .60), PGIC (mean difference= 0.24, 95% CI, -0.13 to 0.60; P = .21), DNS (mean change difference = 0.14, 95% CI, -0.35 to 0.63; P = .58), DNE (mean change difference = 0.26, 95% CI, -0.35 to 0.86; P = .41) and NDS (mean change difference = 0.30, 95% CI, -0.02 to 0.63; P = .07).

CONCLUSIONS

No significant differences were observed in the efficacy of duloxetine and gabapentin when treating patients with PDPN.

A randomized control trial of duloxetine and gabapentin in painful diabetic neuropathy

BACKGROUND

To analyze the efficacy and safety of duloxetine and gabapentin in painful diabetic neuropathy (PDN).

METHODS

A randomized, open-label, active control, 12-week trial was conducted. A total of 86 participants were randomized in 1:1 ratio into gabapentin 300 mg and duloxetine 60 mg groups. The primary efficacy objective was comparison of mean change in Visual Analogue Scale (VAS) (0-100 points) scores between duloxetine and gabapentin. The symptom scores and adverse events were assessed as secondary outcomes.

RESULTS

Statistically significant (P value<.001) improvement was observed in VAS scores in both duloxetine group and gabapentin group at 12 weeks as compared to baseline. However, no significant difference in VAS scores between duloxetine and gabapentin. Similar improvement in diabetic neuropathy symptoms (DNS), diabetic neuropathy examination (DNE), and neuropathic disability score (NDS) was observed in either group over 12 weeks. There were no significant differences in DNS (P = 0.578), DNE (P = 0.410), and NDS (P = 0.071) scores between the two treatment groups. The overall safety evaluation of both duloxetine and gabapentin were similar. The most common adverse events reported were gastrointestinal.

CONCLUSION

The results indicated that both drugs were effective for the symptomatic relief from PDN and had similar efficacy. Follow-up of patients was only for 12 weeks and therefore the long-term efficacy and safety of the study drugs could not be assessed.

Pharmacotherapeutic Options for Managing Neuropathic Pain: A Systematic Review and Meta-Analysis

Despite an increasing number of available therapies, the treatment of neuropathic pain remains a major issue. Systematic reviews and meta-analyses indicate that only a minority of patients with neuropathic pain have an adequate response to pharmacological treatment and that most drugs have dose-limiting side effects. We conducted a systematic review and meta-analysis of randomised controlled trials published in the last five years. We searched for relevant papers within PubMed, EMBASE, the Cochrane Database of Systematic Reviews, and the Clinical Trials database (ClinicalTrials.gov). Two authors independently selected studies for inclusion, data extraction, and bias assessment. We identified 39 randomised controlled trials and included 16 in the meta-analysis. Trial outcomes were generally modest even for first-line drugs such as tricyclic antidepressants, serotonin-noradrenaline reuptake inhibitors, and gabapentinoids. Many drugs acting on new pain targets are currently under development. Clinical data are currently available for sodium channel isoform-specific antagonists, anti-nerve growth factor molecules, and fatty acid amide hydrolase inhibitors.

Diabetic Neuropathy: a Critical, Narrative Review of Published Data from 2019

PURPOSE OF REVIEW

This manuscript is a systematic, narrative review that compiles and describes all data available from 2019 related to epidemiologic, diagnostic, and therapeutic advances in diabetic neuropathy (DN).

RECENT FINDINGS

Epidemiology of DN is discussed. Diagnostic modalities include predictive models, electrodiagnostics, imaging, and biomarkers. A majority of studies on the treatment of diabetic peripheral neuropathy (DPN) involve pharmacotherapy, but complementary and alternative medicine, exercise, modalities, psychological, interventional, and surgical options are also explored. DN is a highly prevalent and debilitating consequence of diabetes that can present challenges to the clinician as the assessment is largely subjective with different phenotypic presentations among patients. Treatment of DN is largely symptomatic as the pathogenesis of DN is not fully understood and is likely multifactorial. It is evident from the broad range of treatments that too often provide unsatisfactory relief that there is no consensus about a single most effective treatment for DN, and monotherapy rarely proves to be successful.

Multitargeting the sleep-pain interaction with pharmacological approaches: A narrative review with suggestions on new avenues of investigation

The multimorbidity formed by sleep disturbances and pain conditions is highly prevalent and has a significant impact in global health and in the socioeconomic system. Although different approaches have been directed toward its management, evidence regarding an optimal treatment is lacking, and pharmacological options are often preferred. Health professionals (e.g., pain and sleep clinicians) tend to focus on their respective expertise, targeting a single symptom with a single drug. This may increase polypharmacy and the risk of drug interactions, adverse events, and mortality. Hence, the use of medications that can directly or indirectly improve sleep, pain, and other possible accompanying conditions without exacerbating them becomes especially relevant. The objectives of this comprehensive review are to: a) describe the beneficial or deleterious effects that some commonly used medications to manage pain have on sleep and sleep disorders; and b) describe the beneficial or deleterious effects that frequently prescribed medications for sleep may have on pain. Moreover, medications targeting some specific sleep-pain interactions will be suggested and future directions for improving sleep and alleviating pain of these patients will be provided with clinical and research perspectives.

Pharmacological Management of Painful Peripheral Neuropathies: A Systematic Review

Introduction

Peripheral neuropathic pain (PNP) arises either acutely or in the chronic phase of a lesion or disease of the peripheral nervous system and is associated with a notable disease burden. The management of PNP is often challenging. The aim of this systematic review was to evaluate current evidence, derived from randomized controlled trials (RCTs) that have assessed pharmacological interventions for the treatment of PNP due to polyneuropathy (PN).

Methods

A systematic search of the PubMed database led to the identification of 538 papers, of which 457 were excluded due to not meeting the eligibility criteria, and two articles were identified through screening of the reference lists of the 81 eligible studies. Ultimately, 83 papers were included in this systematic review.

Results

The best available evidence for the management of painful diabetic polyneuropathy (DPN) is for amitriptyline, duloxetine, gabapentin, pregabalin and venlafaxine as monotherapies and oxycodone as add-on therapy (level II of evidence). Tramadol appears to be effective when used as a monotherapy and add-on therapy in patients with PN of various etiologies (level II of evidence). Weaker evidence (level III) is available on the effectiveness of several other agents discussed in this review for the management of PNP due to PN.

Discussion

Response to treatment may be affected by the underlying pathophysiological mechanisms that are involved in the pathogenesis of the PN and, therefore, it is very important to thoroughly investigate patients presenting with PNP to determine the causes of this neuropathy. Future RCTs should be conducted to shed more light on the use of pharmacological approaches in patients with other forms of PNP and to design specific treatment algorithms.

Electronic supplementary material

The online version of this article (10.1007/s40122-020-00210-3) contains supplementary material, which is available to authorized users.

Usage of antiepileptic drugs in different diseases in Germany - A retrospective study

AIM

The goal of this study was to analyze and quantify the usage of antiepileptic drugs (AEDs) in different diseases and settings in Germany.

METHODS

This retrospective study, based on data from the Disease Analyzer database (IQVIA), included patients from 550 general practices (GP) and 73 neurological practices. Patients who had received at least one prescription for AED from one of these practices between January 2009 and December 2011 (time period 1, n = 39,434) or between January 2016 and December 2018 (time period 2, n = 49,128) were analyzed.

RESULTS

In patients who received AED prescriptions from neurologists, epilepsy (43%) was the most common diagnosis and did not change over time. The proportion of pain diagnoses slightly decreased from 35% in the period from 2009 to 2011 to 34% in the period from 2016 to 2018, while psychiatric disorders increased from 13% to 15%. In GPs, 58% of patients received their AED prescriptions for pain disorders, followed by epilepsy (29%) in the period from 2009 to 2011. The proportion of pain patients slightly increased to 60%, while that of patients with epilepsy slightly decreased to 27%.

CONCLUSIONS

The main indications for which AEDs are prescribed vary with the type of medical practice. The different indications for different AEDs changed between the two time periods, which is in line with the state of the research.

The use of antineuropathic medications for the treatment of chronic pain

Chronic pain syndromes cost the US healthcare system over $600 billion per year. A subtype of chronic pain is neuropathic pain (NP), which is defined as "pain caused by a lesion or disease of the somatosensory system," according to the International Association for the Study of Pain (IASP). The pathophysiology of neuropathic pain is very complex, and more research needs to be done to find the exact mechanism. Patients that have preexisting conditions such as cancer and diabetes are at high-risk of developing NP. Many NP patients are misdiagnosed and receive delayed treatment due to a lack of a standardized classification system that allows clinicians to identify, understand, and utilize pain management in these patients. Medications like tricyclic antidepressants, serotonin-norepinephrine reuptake Inhibitor (SNRIs), and gabapentinoids are first-line treatments followed by opioids, cannabinoids, and other drugs. There are limited studies on the treatment of NP.