[Interventional effect and inflammatory regulation mechanism of dihydroartemisinin combined with pregabalin on neuropathic pain mice].

This study aims to clarify the effects of dihydroartemisinin(DHA) combined with pregabalin(PGB) on neuropathic pain(NP) in mice and explore the neuroinflammatory regulatory mechanism. NP mice model was established using spinal nerve ligation, whereas the sham group exposed the spinal nerve without ligation. The mice were randomly divided into sham group, model group, PGB groups of low, medium, and high doses(PGB-L, PGB-M, and PGB-H, with 22, 45, and 91 mg·kg~(-1)), DHA group(16 mg·kg~(-1)), and DHA combined with PGB groups of low, medium, and high doses(DHA + PGB-L, DHA + PGB-M, and DHA + PGB-H). Administration by gavage 18 days after modeling. Von Frey and cold plate were used to detect mechanical pain threshold and cold pain sensitivity in mice. The tail suspension test and forced swimming test were used to investigate depressive behavior, and the open field test was used to estimate anxiety behavior. The Morris water maze was used to evaluate cognitive function. Liquid suspension chip technology was used to quantitatively analyze immune inflammation-related factors. Immunofluorescence was used to detect the expression of CC chemokine ligand 3(CCL3) and transmembrane protein 119(TMEM119). The results showed that compared with the sham group, the mechanical pain and cold pain sensitivity thresholds of the model group were significantly reduced, and the struggle time was significantly increased in the tail suspension test and forced swimming test. The activity time in the central area was significantly reduced in the open field test. The residence time in the second/fourth quadrant was significantly longer than that in other quadrants, and the latency time of platform climbing significantly increased after platform withdrawal in the Morris water maze experiment. The expression of CCL3 was significantly increased; the number of TMEM119 positive cells and the cell body area were significantly increased. Compared with the model group, the DHA + PGB-M group showed a significant increase in mechanical pain and cold pain sensitivity thresholds, as well as a significant increase in struggle time in the tail suspension test and forced swimming test. The activity time in the central area of the open field test was significantly reduced. The residence time in the second/fourth quadrant was significantly shorter than that in other quadrants, and the latency time of platform climbing after platform withdrawal was significantly reduced. Compared with the PGB-M group, the mechanical pain threshold of D14-17 in the DHA + PGB-M group was significantly increased, and the struggle time during forced swimming was significantly increased. The residence time in the second/fourth quadrant of the Morris water maze was significantly shorter than that in other quadrants. Compared with the model group, the expression of CCL3, the number of TMEM119 positive cells, and the cell body area in the DHA + PGB-M group were significantly decreased. This study indicates that DHA + PGB can enhance the analgesic effect of PGB on NP mice, break through the limitations of PGB tolerance, and make up for the shortcomings of PGB in antidepressant and cognitive improvement. Its mechanism may be related to regulating neuroinflammation by inhibiting the activation of microglial cells and expression of CCL3.

Comparison of the analgesic effects of single-dose 75 mg oral pregabalin versus single-dose 400 mg oral ibuprofen after impacted third mandibular molar surgery: A randomized, double-blind, split-mouth clinical trial.

BACKGROUND: Pain is the most prevalent complication after dentoalveolar surgery. Failure in effective pain control could potentially lead to systemic sequels, such as tachycardia, hypertension, improper nutrition, and central sensitization. Pregabalin is a gamma-aminobutyric acid (GABA) analog with inhibitory and analgesic effects on the central nervous system (CNS). Prescribing gabapentinoids as complementary analgesics reduces the consumption of opioid and non-opioid analgesics, and consequently their side effects. OBJECTIVES: The main purpose of the present study was to compare the analgesic effects of pregabalin (single-dose 75 mg) vs. ibuprofen (single-dose 400 mg) on patients' pain levels after impacted third mandibular molar surgery. MATERIAL AND METHODS: In this randomized, double-blind, split-mouth clinical trial, 24 patients aged 19-34 years volunteered for 2 consecutive (1 month apart) third mandibular molar surgeries (the contralateral teeth). The patients were randomly placed into 2 groups: group G1 (n = 12) was prescribed pregabalin (single-dose 75 mg) after the 1st surgery and ibuprofen (single-dose 400 mg) after the 2nd surgery; and group G2 (n = 12) was prescribed the exact opposite of the G1 arrangement. During the first 24 h post-surgery, the patients recorded the number of complementary analgesics they took (single-dose 400 mg ibuprofen) and their level of pain on a visual analog scale (VAS) every 2 h. RESULTS: The average level of pain at 2 h post-surgery (T1) was significantly lower when pregabalin was prescribed (p < 0.05). Most patients needed complementary analgesics at 4 h post-surgery (T2). However, during the first 24 h post-surgery, the patients required significantly more complementary analgesics when ibuprofen was prescribed. CONCLUSIONS: In comparison with oral ibuprofen (single-dose 400 mg), oral pregabalin (single-dose 75 mg) had a stronger analgesic effect at 2 h after impacted third mandibular molar surgery (p < 0.05). Pregabalin resulted in a significantly lower consumption of complementary analgesics in the first 24 h post-surgery as compared to ibuprofen.

Therapeutic Strategies for Postherpetic Neuralgia: Mechanisms, Treatments, and Perspectives.

PURPOSE OF REVIEW: Postherpetic neuralgia is an annoying pain that mainly affects older people. In order to give patients more options, this review summarizes the pharmacological and interventional treatments for postherpetic neuralgia and updates the research on the efficacy, thereby providing doctors with more treatment options. The adverse effects and effective doses of its various treatments are also presented so that the therapy can be prescribed according to their concrete physical conditions. In a word, this review is dedicated to providing a comprehensive overview of the treatment options for postherpetic neuralgia and offering patients more choices. RECENT FINDINGS: Combinational therapy is more excellent than monotherapy. The local anesthesia and gabapentin comprised outstanding compatibility. In addition, two therapeutic tools for PHN patients, especially for the intractable ones, electroacupuncture (EA), and osteopathic manipulative treatment (OMT), show their efficacy and become potential options to alleviate pain. In terms of treatment, guidelines recommend patients use tricyclic antidepressants (TCAs), gabapentin, pregabalin, and 5% lidocaine patches as the first-line medications, and gabapentin is investigated most, especially the gabapentin enacarbil (GEn). And drug efficacy can be limited by adverse effects and tolerated doses. Interventional treatments, with their invasiveness and operational difficulty, are usually considered for intractable patients. Combinational therapies may be used when a single therapy cannot achieve the desired effect. Therapies such as OMT and EA have also been proposed to palliate pain in some cases, and future directions of treatment may be investigated in Chinese medicine and acupuncture.

Palmitoylethanolamide and acetyl-L-carnitine act synergistically with duloxetine and pregabalin in fibromyalgia: results of a randomised controlled study.

OBJECTIVES: Fibromyalgia (FM) is characterised by a form of debilitating pain that is unresponsive to standard analgesics. The aim of this study was to evaluate the efficacy of supplementing ongoing pregabalin (PGB) and duloxetine (DLX) treatment with palmitoylethanolamide (PEA) and acetyl-L-carnitine (ALC) for 24 weeks in FM patients. METHODS: After undergoing three months of stable treatment with DLX+PGB, FM patients were randomised to continue the same treatment (Group 1) or to add PEA 600 mg b.i.d + ALC 500 mg b.i.d. (Group 2) for a further 12 weeks. Every two weeks throughout the study, cumulative disease severity was estimated using the Widespread Pain Index (WPI) as the primary outcome measure; the secondary outcomes were the fortnightly scores of the patient-completed revised Fibromyalgia Impact Questionnaire (FIQR) and the modified Fibromyalgia Assessment Status (FASmod) questionnaire. All three measures were expressed as time-integrated area under the curve (AUC) values. RESULTS: One hundred and thirty (91.5%) of the initial 142 FM patients completed the study: 68 patients in Group 1 and 62 in Group 2. Twenty-four weeks after randomisation, the Group 2 patients showed additional significant improvements in all three outcome measures. Although there was some fluctuation in both groups during the study period, the AUC values of the WPI scores steadily decreased in Group 2 (p=0.048), which also showed better outcomes in terms of the AUC values of the FIQR (p=0.033) and FASmod scores (p=0.017). CONCLUSIONS: This is the first randomised controlled study demonstrating the effectiveness of the adding on therapy of PEA+ALC to DLX+PGB in FM patients.

Reasons for use and experiences of using phenibut, a mixed methods analysis of online reports.

Background: Phenibut is a drug similar in structure to gabapentin and pregabalin. It is available online without prescription, often marketed as a dietary supplement or amino acid derivative. Little is known about phenibut use despite its increased popularity in the United States over the last decade.Objective: To clarify reasons for taking phenibut, circumstances, and effects of use.Methods: Reports of phenibut, gabapentin, and pregabalin use were downloaded from a publicly-available database, Erowid.org. A mixed methods approach utilizing qualitative content analysis was used.Results: Of 229 reports, 211 were from male authors. People usually purchased phenibut online and reportedly used it for recreation, to manage a medical or psychiatric problem (primarily insomnia, anxiety), as a substitute for other drugs (especially benzodiazepines), to manage withdrawal from another substance (including benzodiazepines, opioids), and/or for performance enhancement. While it shared many reported effects with pregabalin and gabapentin such as anxiolysis, increased talkativeness, and impaired motor coordination, reports of gastrointestinal distress and sedation were more commonly attributed to phenibut. Several people reported difficulty in restricting their use and managing withdrawal.Conclusions: Phenibut reports suggest that phenibut may have some benefits for some people. Use also, however, carries risks of adverse effects, a potentially dangerous withdrawal syndrome, and addiction. Not dissimilar to unprescribed gabapentin or pregabalin, self-medication is a common motive for phenibut use. Physicians should continue to ask their patients about use of any non-prescribed medications, dietary supplements, or "amino acid derivatives."Abbreviation: PWUPh: people who use phenibut; PWUG: people who use gabapentin; PWUPr: people who use pregabalin.

Combination analgesic development for enhanced clinical efficacy (the CADENCE trial): a double-blind, controlled trial of an alpha-lipoic acid-pregabalin combination for fibromyalgia pain.

ABSTRACT: Drug therapy for fibromyalgia is limited by incomplete efficacy and dose-limiting adverse effects (AEs). Combining agents with complementary analgesic mechanisms-and differing AE profiles-could provide added benefits. We assessed an alpha-lipoic acid (ALA)-pregabalin combination with a randomized, double-blind, 3-period crossover design. Participants received maximally tolerated doses of ALA, pregabalin, and ALA-pregabalin combination for 6 weeks. The primary outcome was daily pain (0-10); secondary outcomes included Fibromyalgia Impact Questionnaire, SF-36 survey, Medical Outcomes Study Sleep Scale, Beck Depression Inventory (BDI-II), adverse events, and other measures. The primary outcome of daily pain (0-10) during ALA (4.9), pregabalin (4.6), and combination (4.5) was not significantly different ( P = 0.54). There were no significant differences between combination and each monotherapy for any secondary outcomes, although combination and pregabalin were both superior to ALA for measures of mood and sleep. Alpha-lipoic acid and pregabalin maximal tolerated doses were similar during combination and monotherapy, and AEs were not frequent with combination therapy. These results do not support any additive benefit of combining ALA with pregabalin for fibromyalgia. The observation of similarly reached maximal tolerated drug doses of these 2 agents (which have differing side-effect profiles) during combination and monotherapy-without increased side effects-provides support for future development of potentially more beneficial combinations with complementary mechanisms and nonoverlapping side effects.

Case Series: Synergistic Effect of Gabapentin and Adjuvant Pregabalin in Neuropathic Pain.

Gabapentin and pregabalin both exert high affinity to the α2δ subunit of the voltage-gated calcium channels which inhibits excitatory neurotransmitter release. The synergistic mechanism was described in rats given combinations of gabapentin and pregabalin. In this case series, we described 2 cases which may illustrate the synergistic effect of gabapentin and pregabalin in treatment resistant neuropathic pain. Low dose pregabalin was added to therapeutic gabapentin to achieve appreciable pain reduction in one case and improved quality of life in another case. Further research with more enrollment and longer study duration may help elucidate the appropriate dosing and potential associated side effects.

Pregabalin supplementation for the pain relief of septorhinoplasty: a meta-analysis study.

BACKGROUND: Pregabalin supplementation may have some potential in improving pain relief in patients with septorhinoplasty, and this meta-analysis aims to explore the impact of pregabalin supplementation on pain control for septorhinoplasty. METHODS: PubMed, EMbase, Web of science, EBSCO and Cochrane library databases were systematically searched, and we included randomized controlled trials (RCTs) assessing the effect of pregabalin supplementation on pain control for septorhinoplasty. RESULTS: Six RCTs were finally included in the meta-analysis. Overall, when compared with control intervention for septorhinoplasty, pregabalin intervention showed significantly reduced pain scores at 1 h (SMD - 1.05; 95% CI - 1.85 to - 0.24; P = 0.01), 2 h (SMD - 1.01; 95% CI - 1.83 to - 0.20; P = 0.02), 6 h (SMD - 1.00; 95% CI - 1.47 to - 0.54; P < 0.0001) and 12 h (SMD - 0.69; 95% CI - 1.35 to - 0.02; P = 0.04), as well as rescue analgesics (OR 0.17; 95% CI 0.07 to 0.44; P = 0.0002), but had no notable influence on nausea and vomiting (OR 0.67; 95% CI 0.30 to 1.46; P = 0.31), or drowsiness (OR 1.22; 95% CI 0.64 to 2.35; P = 0.54). CONCLUSIONS: Pregabalin supplementation benefits to pain control after septorhinoplasty.

Medidas para optimizar cuidados post rinoplastia. Revisión sistemática de la literatura / Measures to optimize rhinoplasty post operative care, systematic review of the literature

Introducción: El cuidado postoperatorio de la rinoplastia ha evolucionado, paralelamente, al desarrollo de la técnica quirúrgica. Existen varias recomendaciones, sin embargo, hay una gran variabilidad interprofesional de las indicaciones post quirúrgicas. Objetivo: Realizar una revisión sistemática de la literatura científica sobre los cuidados post operatorios de la rinoplastia. Material y Método: Para la realización de este estudio se llevaron a cabo búsquedas en PubMed y en Cochrane Database of Systematic Reviews con los perfiles: ([rhinoplasty] AND [post operative care]) y ([rhinoplasty] AND [post surgical care]). Se seleccionaron los artículos publicados en los últimos 10 años, desde 2013 hasta 2023, ambos inclusive. Resultados: Los documentos analizados recogen la evidencia de los diferentes métodos de cuidados post quirúrgicos en rinoplastia. Estos confirman la utilización de corticoides en el período postoperatorio, así como el reposo en 90° y exponen la variabilidad interprofesional que existe en el protocolo postquirúrgico de esta cirugía. Conclusión: El uso de corticoides y el reposo en 90° disminuyen las complicaciones postquirúrgicas de la rinoplastia. Debe existir una clara información sobre lo que el paciente debe esperar post cirugía. El uso de opioides debe ser restringido y la analgesia debe ser multimodal. Es preciso realizar estudios futuros con mayor nivel de evidencia y tener protocolos uniformes para la práctica clínica.

Introduction: The postoperative care of rhinoplasty has evolved along with the development of the surgical technique. There are several recommendations, however there is enormous interprofessional variability of post-surgical indications. Aim: To carry out a systematic review of the scientific literature on rhinoplasty postoperative care. Material and Method: To carry out this study, searches were carried out in PubMed and in the Cochrane Database of Systematic Reviews with the profiles: ([rhinoplasty] AND [post operative care]) and ([rhinoplasty] AND [post surgical care]). Articles published in the last 10 years were selected, from 2013 to 2023, both inclusive. Results: The documents analyzed collect the evidence of the different methods of post-surgical care in rhinoplasty, they confirm the use of corticosteroids in the postoperative period as well as rest at 90° and expose the interprofessional variability that exists in the post-surgical protocol of this surgery. Conclusion: The use of corticosteroids and rest at 90° reduce the post-surgical complications of rhinoplasty. There must be clear information about what the patient should expect post surgery. The use of opioids must be restricted and analgesia must be multimodal. It is necessary to carry out future studies with a higher level of evidence and have uniform protocols for clinical practice.

Efficacy and safety of different antidepressants and anticonvulsants in central poststroke pain: A network meta-analysis and systematic review.

OBJECTIVE: To evaluate the efficacy and safety of different antidepressants and anticonvulsants in the treatment of central poststroke pain (CPSP) by network meta-analysis and provide an evidence-based foundation for clinical practice. METHODS: PubMed, Cochrane Library, EMBASE, CNKI, APA PsycINFO, Wanfang, VIP and other databases were searched by computer to find clinical randomized controlled studies (RCTs) on drug treatment of CPSP. The retrieval time limit was from the establishment of each database to July 2022. The quality of the included RCTs was evaluated using the bias risk assessment tool recommended by Cochrane. Stata 14.0 was used for network meta-analysis. RESULTS: A total of 13 RCTs, 1040 patients and 9 drugs were finally included. The results of the network meta-analysis showed that the effectiveness ranking as rated by the visual analog scale (VAS) was gabapentin > pregabalin > fluoxetine > lamotrigine > duloxetine > serqulin > amitriptyline > carbamazepine > vitamin B. Ranking according to the numerical rating scale (NRS) was pregabalin > gabapentin > carbamazepine. Ranking derived from the Hamilton depression scale (HAMD) was pregabalin > duloxetine > gabapentin > amitriptyline. CONCLUSION: All nine drugs can relieve the pain of CPSP patients to different degrees; among them pregabalin and gabapentin have the most significant effect, and gabapentin and pregabalin also have the most adverse reactions. In the future, more multicenter, large sample, double-blind clinical randomized controlled trials need to be carried out to supplement and demonstrate the results of this study.

Treatment modalities in brachioradial pruritis: a systematic review.

INTRODUCTION: Brachioradial pruritis is a rare dysesthesia syndrome that is known to negatively impact quality of life. No consensus exists regarding optimal treatment strategies. METHODS: We searched MEDLINE, EMBASE, and the Cochrane Collaboration Clinical Trials Registry from 1966 to 2021 for studies using the title word "brachioradial pruritis" with no language restriction. One author (A.Z.) screened and performed full article reviews of all randomized clinical trials, cohort studies, case-control studies, case reports, and case series describing treatment outcomes among patients with brachioradial pruritis. RESULTS: We identified 239 potential articles with a final set of 45 articles meeting inclusion criteria. Only a single randomized clinical trial was identified, finding no significant benefit of topical capsaicin cream. Treatment modalities with the greatest number of reported successful therapeutic trials include gabapentin and tricyclic antidepressants. In patients with confirmed cervical spine disease, spine-directed therapies such as epidural injections were found to be beneficial. Case reports and small case series describing less-common treatments were also identified. DISCUSSION: The literature is overall limited with the greatest support for gabapentin, pregabalin, tricyclic antidepressants, and spine-directed therapies in appropriate patients with brachioradial pruritis. Future randomized clinical trials are needed to compare the relative effectiveness of available treatments.

Coenzyme Q10 as a potential add-on treatment for patients suffering from painful diabetic neuropathy: results of a placebo-controlled randomized trial.

BACKGROUND: We hypothesized that the addition of coenzyme Q10 (CoQ10) to pregabalin might be helpful in improving symptoms in patients suffering from painful diabetic neuropathy (PDN). METHODS: One hundred twelve patients with PDN were randomly allocated to receive CoQ10 + pregabalin (57 patients) or placebo + pregabalin (55 patients). Besides pregabalin (150 mg/day), the patients, upon their group assignment, received CoQ10 at a dosage of 100 mg every 8 h or matched placebo for 8 consecutive weeks. The primary efficacy measure was the changes in the pain intensity from baseline to endpoint measured on an 11-point NRS (numeric rating scale). Secondary efficacy measures included the changes in the pain-associated sleep interference score (SIS) as well as the patients' global improvement with treatment measured on the Clinicians' and Patients' Global Impression of Change (CGIC/PGIC). RESULTS: On the intent­to­treat population (ITT) analysis, the CoQ10 + pregabalin regimen resulted in significantly greater pain relief than the placebo + pregabalin regimen. By the end of week 2, the decrease in the mean pain NRS score was similar in both groups, but at the end of weeks four and eight, the decrease in the mean pain NRS score was significantly greater in patients taking CoQ10 + pregabalin than in those taking placebo + pregabalin (p value = 0.01 and < 0.001, respectively). Likewise, at the end of week 8, the decrease in the pain-associated SIS was significantly greater in the patients supplemented with CoQ10 compared to placebo. Furthermore, the proportion of the responder patients (those having ≥ 50% decline in the mean pain NRS score) as well as the proportion of patients rated ''very much'' or ''much improved'' on the CGIC/PGIC scales were also significantly higher in the CoQ10 + pregabalin-treated patients than placebo + pregabalin-treated patients. CONCLUSIONS: Our data support the idea that diabetic patients suffering from PDN may benefit from using antioxidant and anti-inflammatory supplements like CoQ10. However, further studies are required before supplementation with CoQ10 can be recommended for treating PDN. TRIAL REGISTRATION: The trial was registered at Iranian Registry of Clinical Trials (identifier code: IRCT20120215009014N385). Registration date: 2021-02-21.

Xiaoketongbi Formula vs pregabalin for painful diabetic neuropathy: A single-center, randomized, single-blind, double-dummy, and parallel controlled clinical trial.

BACKGROUND: We assessed the efficacy and safety of the Xiaoketongbi Formula (XF) vs. pregabalin in patients with painful diabetic neuropathy (PDN). METHODS: Patients with PDN (n = 68) were included in a single-center, randomized, single-blind, double-dummy, parallel controlled clinical trial. The primary outcome was the change in the Brief Pain Inventory for Diabetic Peripheral Neuropathy (BPI-DPN). Secondary outcomes evaluated included the reduction of BPI-DPN >50%, changes in the numeric rating scale-11 (NRS-11) score for pain, Daily Sleep Interference Diary (DSID), Patient Global Impression of Change (PGIC), nerve conduction velocity (NCV), and adverse events. RESULTS: After 10 weeks of treatment, the BPI-DPN score reduced from 42.44 ± 17.56 to 26.47 ± 22.22 and from 52.03 ± 14.30 to 37.85 ± 17.23 in the XF and pregabalin group (Ps < 0.001), respectively. The difference in the absolute change in BPI-DPN score between both groups was -1.79 (95% CI: -9.09, 5.50; p = 0.625). In the XF and pregabalin groups, 44.1% (15/34) and 20.6% (7/34) of patients reported a BPI-DPN reduction >50% (p = 0.038), respectively. There were no significant differences between groups in NRS-11 and DSID (Ps > 0.05). A significantly greater number of patients in the XF group felt "significantly improved" or "improved" than in the pregabalin group (35.3% (12/34) vs. 11.8% (4/34), p = 0.045). The absolute change in motor nerve conduction velocity of the right median nerve was significantly different between both groups (XF group 0.7 ± 2.3 vs. pregabalin group -2.2 ± 4.1, p = 0.004). No serious adverse events were reported in either group. CONCLUSIONS: XF is equivalent to pregabalin in reducing pain symptoms and improves the quality of life in patients with PDN. In addition, XF has the potential to improve nerve function by increasing NCV.

Comparison of amitriptyline supplemented with pregabalin, pregabalin supplemented with amitriptyline, and duloxetine supplemented with pregabalin for the treatment of diabetic peripheral neuropathic pain (OPTION-DM): a multicentre, double-blind, randomised crossover trial.

BACKGROUND: Diabetic peripheral neuropathic pain (DPNP) is common and often distressing. Most guidelines recommend amitriptyline, duloxetine, pregabalin, or gabapentin as initial analgesic treatment for DPNP, but there is little comparative evidence on which one is best or whether they should be combined. We aimed to assess the efficacy and tolerability of different combinations of first-line drugs for treatment of DPNP. METHODS: OPTION-DM was a multicentre, randomised, double-blind, crossover trial in patients with DPNP with mean daily pain numerical rating scale (NRS) of 4 or higher (scale is 0-10) from 13 UK centres. Participants were randomly assigned (1:1:1:1:1:1), with a predetermined randomisation schedule stratified by site using permuted blocks of size six or 12, to receive one of six ordered sequences of the three treatment pathways: amitriptyline supplemented with pregabalin (A-P), pregabalin supplemented with amitriptyline (P-A), and duloxetine supplemented with pregabalin (D-P), each pathway lasting 16 weeks. Monotherapy was given for 6 weeks and was supplemented with the combination medication if there was suboptimal pain relief (NRS >3), reflecting current clinical practice. Both treatments were titrated towards maximum tolerated dose (75 mg per day for amitriptyline, 120 mg per day for duloxetine, and 600 mg per day for pregabalin). The primary outcome was the difference in 7-day average daily pain during the final week of each pathway. This trial is registered with ISRCTN, ISRCTN17545443. FINDINGS: Between Nov 14, 2017, and July 29, 2019, 252 patients were screened, 140 patients were randomly assigned, and 130 started a treatment pathway (with 84 completing at least two pathways) and were analysed for the primary outcome. The 7-day average NRS scores at week 16 decreased from a mean 6·6 (SD 1·5) at baseline to 3·3 (1·8) at week 16 in all three pathways. The mean difference was -0·1 (98·3% CI -0·5 to 0·3) for D-P versus A-P, -0·1 (-0·5 to 0·3) for P-A versus A-P, and 0·0 (-0·4 to 0·4) for P-A versus D-P, and thus not significant. Mean NRS reduction in patients on combination therapy was greater than in those who remained on monotherapy (1·0 [SD 1·3] vs 0·2 [1·5]). Adverse events were predictable for the monotherapies: we observed a significant increase in dizziness in the P-A pathway, nausea in the D-P pathway, and dry mouth in the A-P pathway. INTERPRETATION: To our knowledge, this was the largest and longest ever, head-to-head, crossover neuropathic pain trial. We showed that all three treatment pathways and monotherapies had similar analgesic efficacy. Combination treatment was well tolerated and led to improved pain relief in patients with suboptimal pain control with a monotherapy. FUNDING: National Institute for Health Research (NIHR) Health Technology Assessment programme.

Co-Combination of Pregabalin and Withaniacoagulans-Extract-Loaded Topical Gel Alleviates Allodynia and Hyperalgesia in the Chronic Sciatic Nerve Constriction Injury for Neuropathic Pain in Animal Model.

The current study reports the fabrication of co-combination gel using Pregabalin and Withania coagulans fruit extract to validate its effectiveness for neuropathic pain in chronic constriction injury (CCI) rat models. Three topical gels were prepared using Carbopol 934 through a pseudo-ternary phase diagram incorporating the Pregabalin (2.5%), Withania coagulans extract (2%), and co-combination of both Pregabalin (2.5%) and Withania coagulans extract (2%). Gels were characterized. FTIR showed a successful polymeric network of the gel without any interaction. The drug distribution at the molecular level was confirmed by XRD. The AFM images topographically indicated the rough surface of gels with a size range from 0.25 to 330 nm. DSC showed the disappearance of sharp peaks of the drug and extract, showing successful incorporation into the polymeric network of gels. The in vitro drug release of co-combination gel was 73% over 48 h. The mechanism of drug release by combination gel was Higuchi+ fickian with values of n (0.282) and R2 (0.947). An in vivo study for pain assessment via four methods: (i) heat hyperalgesia, (ii) cold allodynia, (iii) mechano-hyperalgesia, and (iv) dynamic mechano-allodynia, confirmed that topical treatment with co-combination gel reduced the pain significantly as indicated by the p value: R1 (p < 0.001), R2 (p < 0.001), R3 (p < 0.015), and R4 (p < 0.0344). The significance order was R2 (****) > R1 (***) > R3 (**) > R4 (*) > R5 (ns).

Gabapentinoids and Acetaminophen as Adjuvants for Managing Postoperative Pain.

With the current opiate epidemic in the United States, there is renewed interest in evaluating non-opiate adjuvant medications as effective alternatives for the prevention and treatment of postoperative pain. A systematic review of randomized, controlled trials on Pub Med, Medline, and Embase was conducted looking on postoperative pain management from 2008 to 2018. Studies were included if they used a gabapentenoid with or without acetaminophen and evaluated supplemental opiate use. All adult (18 years or older) surgical populations were considered for inclusion, and fourteen clinical trials met inclusion criteria. Gabapentenoid dosing varied among studies. In nine of fourteen studies, there was a finding of superiority as compared to placebo in managing postoperative pain and decreasing supplemental opiate use. Pregabalin was used in twelve of the fourteen studies and gabapentin was used in two of the fourteen studies. Of the nine studies that found a benefit from using a gabapentoid, all included pregabalin. While the rate of adverse effects was low in all studies, it was found to increase as dosages increased. Results support that pregabalin has a role in decreasing postoperative pain intensity and supplemental opiate use; however, the optimal dose or dosing regimen is not yet well understood.

Potential Molecular Mechanisms of Electroacupuncture With Spatial Learning and Memory Impairment Induced by Chronic Pain on a Rat Model.

BACKGROUND: It is frequently reported that neuropathic pain is associated with abnormalities in brain function and structure as well as cognitive deficits. However, the contributing mechanisms have remained elusive. OBJECTIVES: We aimed to investigate the systemic ultrastructural changes of the peripheral nervous system (PNS) and central nervous system (CNS) in rats with trigeminal neuralgia (TN) induced by cobra venom, as well as the effects and mechanisms of electroacupuncture (EA) and pregabalin (PGB) on TN. STUDY DESIGN: This study used an experimental design in rats. SETTING: The research took place in the laboratory at the Aviation General Hospital of China Medical University and Beijing Institute of Translational Medicine. METHODS: Male Sprague-Dawley rats were randomly divided into 4 groups (n = 12/group): cobra venom (CV), PGB, EA, and sham-operated (SHAM). The development of pain-related behaviors and spatial learning and memory abilities were measured using video recordings and Morris water maze tests, respectively. The ultrastructural changes of the PNS and CNS were examined using transmission electron microscopy. We also screened the differentially expressed genes and proteins in the prefrontal cortex  and hippocampus using  ribonucleic acid sequencing and isobaric tag for relative and absolute quantitation techniques, respectively. Data for the behavioral tests and molecular biology were analyzed with a one-way analysis of variance. RESULTS: The rats in the CV group exhibited long-lasting pain-like behaviors, cognitive deficits, and systemic ultrastructural changes. Both EA and PGB alleviated the chronic pain syndrome, but EA also inhibited the chronic pain-induced cognitive dysfunction and restored normal cellular structures, while PGB was associated with no improvements. Transcriptomic and proteomic analyses revealed marcks, pak2 and acat1 were altered in rats with TN but were adjusted back to baseline by EA but not by PGB. LIMITATIONS: We examined systemic ultrastructural alterations at different levels of the nervous system; however, the detailed timeline of the damage process was not explicitly delineated.  Moreover, the current study provides only preliminary evidence for the neurobiological mechanisms of cognitive impairment resulting from chronic pain.  Further research is still necessary (using models such as gene knockout rats and cell cultures) before a detailed mechanism can be postulated. CONCLUSIONS: EA treatment may offer significant advantages when compared to PGB for the treatment of cognitive impairment associated with chronic pain. Moreover, marcks, pak2 and acat1 may be the potential therapeutic targets of EA.

Evaluation of in vitro transdermal permeation, mass spectrometric imaging, and in vivo analgesic effects of pregabalin using a pluronic lecithin organogel formulation in mice.

In clinical practice, pregabalin is orally administered for neuropathic pain, but causes severe central nervous system side effects, such as dizziness, which results in dose limitation or discontinuation. To reduce the central side effects of pregabalin, we developed four pregabalin preparations for transdermal application: 0.4% aqueous solution, pluronic lecithin organogel (PLO gel), hydrophilic cream, and lipophilic cream. Transdermal permeabilities of pregabalin among the four formulations were compared in vitro using hairless mouse skin. The longitudinal distribution of pregabalin within the skin was analyzed using mass spectrometric (MS) imaging. Furthermore, the in vivo analgesic effects of the formulations were evaluated using the von Frey filament test in a mouse model of diabetic neuropathy (DN). The PLO gel showed the highest permeability of pregabalin, followed by the aqueous solution, and no permeation was observed in the two cream formulations. The MS imaging analysis showed that pregabalin was distributed up to the dermis in the PLO gel 1 h after application, while the aqueous solution was distributed near the epidermis. A significant analgesic effect (p < .05) was observed 1.5 h after PLO gel application in the DN model mice, but the aqueous solution had no effect. This study indicated for the first time that pregabalin penetrated beyond the skin epidermis up to the dermis, from the PLO gel formulation, and that the application of this formulation exhibited an in vivo analgesic effect in the mouse model of DN.

Dry needling increases antioxidant activity and grip force in a rat model of muscle pain.

BACKGROUND: Muscle pain syndromes (MPS) are one of the main causes of functional, structural and metabolic problems, being associated with tissue oxidative damage. Although dry needling is widely used in the treatment of MPS, there is little scientific evidence of its efficacy and underlying mechanisms of action. OBJECTIVES: To investigate the effects of different dry needling techniques on thermal and mechanical hyperalgesia, locomotor and functional activity, and oxidative stress markers in a rat model of muscle pain. METHODS: A total of 48 male Wistar rats underwent injection of the gastrocnemius muscle with control neutral saline (pH 7) and remained untreated (Saline group), or acidic saline (pH 4) and remained untreated (ASA group) or received pregabalin (PG group), deep needling (DN group), superficial needling (SN group) or twitch needling (TN group) with n = 8 rats per group. Mechanical (von Frey test) and thermal hyperalgesia (acetone test), muscle edema (assessed with a caliper), strength and muscle function (grip force evaluation), surface thermography and locomotor and exploratory activities (open field test) were evaluated. The animals were then euthanized, and the gastrocnemius muscle was excised for assessment of oxidative analyses of lipid peroxidation with thiobarbituric acid reactive species (TBA-RS) and total glutathione (GSH) levels. RESULTS: All treatments significantly improved muscle strength and function when compared to the AS group (p < 0.05). Pregabalin reduced locomotor and exploratory activities, while the TN intervention increased the antioxidant response (p < 0.05). CONCLUSION: Dry needling improved strength, functionality and locomotor activity in a rat model of muscle pain. Twitch needling induced an antioxidant effect.

Treatment Impact on Patient-Reported Outcomes in Peripheral Neuropathic Pain: Comparing Single Intervention With Topical High-Concentration Capsaicin to Daily Oral Pregabalin.

BACKGROUND: Peripheral neuropathic pain (PNP) is a complex, subjective experience affecting both physical and psychological aspects of functioning. Assessing patient-reported outcomes (PROs) beyond pain relief is important and aligns with the recommendations of IMMPACT (Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials). Moreover, PRO data are key to clinical decision-making when evaluating treatment options. However, direct comparisons between such options are scarce. High-concentration capsaicin 179 mg (8% w/w) cutaneous patch (HCCP) is applied to the skin at minimum intervals of 90 days under physician supervision; alternative recommended treatments for PNP are mostly orally administered on a daily basis. The ELEVATE study directly compared HCCP with pregabalin and found noninferior efficacy of HCCP to pregabalin in relieving pain after 8 weeks, with a significantly faster onset of action and fewer systemic side effects. OBJECTIVES: The objective of this analysis was to compare PRO outcomes defined as secondary objectives of the ELEVATE study after a single intervention with HCCP to daily oral pregabalin for 8 weeks. STUDY DESIGN: ELEVATE was an open-label, randomized (1:1) multicenter study. SETTING: The study included 92 sites in 22 countries in Europe and Asia. METHODS: Five hundred fifty-nine non-diabetic  patients with PNP received a single intervention with HCCP (n = 282; 1-4 patches at baseline) or oral daily pregabalin (n = 277; 150-600 mg, 8 weeks). At baseline (Day 0) and Week 8, patients completed the following PROs in addition to the regular pain assessments: Patient Global Impression of Change (PGIC), Medical Outcomes Study Cognitive Functioning scale (MOS-Cog), Medical Outcomes Study Sleep scale (MOS-Sleep), Treatment Satisfaction Questionnaire for Medication (TSQM), and EuroQol 5-Dimensions 5-levels (EQ-5D-5L) Utility Index (EQ-UI) and Visual Analog Scale (EQ-VAS). RESULTS: At Week 8, 76% and 75.9% of patients on HCCP and pregabalin, respectively, reported to be very much/much/minimally improved on the PGIC. HCCP application was associated with significant improvements from baseline vs. pregabalin in MOS-Cog (mean difference: 4.28 [95% CI: 2.90-5.66]; P < 0.001), EQ-VAS (3.11 [0.30-5.92]; P = 0.030), and TSQM global satisfaction (6.74 [2.29-11.20]; P = 0.029), particularly the side-effects dimension (21.23 [17.55-24.94]; P < 0.0001). No significant differences in improvements were noted for the MOS-Sleep, TSQM convenience, and EQ-UI. LIMITATIONS: The ELEVATE study has an open-label design, with only one comparator (pregabalin); it was limited to 8 weeks. The sample size was determined for the primary endpoint. CONCLUSIONS: A single intervention with HCCP showed benefits vs. daily pregabalin at Week 8 on several PROs. While HCCP has been approved in the United States for PNP treatment in diabetic and PHN patients, these observations provide information on how patients perceive the effects of distinct PNP treatments. They are complementing already existing knowledge on efficacy and safety of different treatment options with data on patient preferences and may help identify the appropriate treatment option in dialogue with the patients and shared decision-making.IRB Approval: At the time of the study, the trial was approved either nationally or at site level. All approvals were granted prior to the initiation of the trial. A list of Ethics Committees that approved the trial is included as a supplemental file. CLINICAL TRIAL REGISTRATION NUMBER: NCT01713426.