The Analgesic Potential of Litsea Species: A Systematic Review.

Various plant species from the Litsea genus have been claimed to be beneficial for pain relief. The PRISMA approach was adopted to identify studies that reported analgesic properties of plants from the Litsea genus. Out of 450 records returned, 19 primary studies revealed the analgesic potential of nine Litsea species including (1) Litsea cubeba, (2) Litsea elliptibacea, (3) Litsea japonica, (4) Litsea glutinosa, (5) Litsea glaucescens, (6) Litsea guatemalensis, (7) Litsea lancifolia, (8) Litsea liyuyingi and (9) Litsea monopetala. Six of the species, 1, 3, 4, 7, 8 and 9, demonstrated peripheral antinociceptive properties as they inhibited acetic-acid-induced writhing in animal models. Species 1, 3, 4, 8 and 9 further showed effects via the central analgesic route at the spinal level by increasing the latencies of heat stimulated-nocifensive responses in the tail flick assay. The hot plate assay also revealed the efficacies of 4 and 9 at the supraspinal level. Species 6 was reported to ameliorate hyperalgesia induced via partial sciatic nerve ligation (PSNL). The antinociceptive effects of 1 and 3 were attributed to the regulatory effects of their bioactive compounds on inflammatory mediators. As for 2 and 5, their analgesic effect may be a result of their activity with the 5-hydroxytryptamine 1A receptor (5-HT1AR) which disrupted the pain-stimulating actions of 5-HT. Antinociceptive activities were documented for various major compounds of the Litsea plants. Overall, the findings suggested Litsea species as good sources of antinociceptive compounds that can be further developed to complement or substitute prescription drugs for pain management.

Thoracotomy Patients Under General Anesthesia: A Comparison on Intra-Operative Anesthetic and Analgesic Requirements, When Combined with Either Epidural Analgesia or Continuous Unilateral Paravertebral Analgesia.

BACKGROUND AND OBJECTIVE: Regional analgesia is effective for post-thoracotomy pain. The primary objective of the study is to compare the intraoperative requirement of isoflurane and fentanyl between general anaesthesia (GA) with epidural analgesia and GA with paravertebral analgesia. METHODS AND MATERIAL: A prospective observational comparative study was conducted on 56 patients undergoing open thoracotomy procedures. The patients were divided into two groups of 28 by assigning the study participants alternatively to each group: Group GAE - received thoracic epidural catheterization with GA, and Group GAP - received ultrasound guided thoracic paravertebral catheterization on the operative side with GA. Intraoperative requirement of isoflurane, fentanyl, postoperative analgesia, stress response, need of rescue analgesics and adverse effects were observed and analysed. RESULTS: 25 patients in each group were included in the data analysis. The intraoperative requirement of isoflurane (32.28 ± 1.88 vs 48.31 ± 4.34 ml; p < 0.0001) and fentanyl (128.87 ± 25.12 vs 157 ± 30.92 µg; p = 0.0009) were significantly less in the GAE group than in the GAP group. VAS scores and need of rescue analgesics and blood glucose levels were not statistically significant during the postoperative period (p > 0.05). The incidence of adverse effects was comparable except for hypotension and urinary retention which were significantly higher in the GAE group. CONCLUSION: GA with epidural analgesia resulted in significant reduction in the intraoperative consumption of isoflurane and fentanyl in comparison to GA with paravertebral analgesia. However, both the techniques were equally effective in the postoperative period.

Anti-Nociceptive Effects of Sphingomyelinase and Methyl-Beta-Cyclodextrin in the Icilin-Induced Mouse Pain Model.

The thermo- and pain-sensitive Transient Receptor Potential Melastatin 3 and 8 (TRPM3 and TRPM8) ion channels are functionally associated in the lipid rafts of the plasma membrane. We have already described that cholesterol and sphingomyelin depletion, or inhibition of sphingolipid biosynthesis decreased the TRPM8 but not the TRPM3 channel opening on cultured sensory neurons. We aimed to test the effects of lipid raft disruptors on channel activation on TRPM3- and TRPM8-expressing HEK293T cells in vitro, as well as their potential analgesic actions in TRPM3 and TRPM8 channel activation involving acute pain models in mice. CHO cell viability was examined after lipid raft disruptor treatments and their effects on channel activation on channel expressing HEK293T cells by measurement of cytoplasmic Ca2+ concentration were monitored. The effects of treatments were investigated in Pregnenolone-Sulphate-CIM-0216-evoked and icilin-induced acute nocifensive pain models in mice. Cholesterol depletion decreased CHO cell viability. Sphingomyelinase and methyl-beta-cyclodextrin reduced the duration of icilin-evoked nocifensive behavior, while lipid raft disruptors did not inhibit the activity of recombinant TRPM3 and TRPM8. We conclude that depletion of sphingomyelin or cholesterol from rafts can modulate the function of native TRPM8 receptors. Furthermore, sphingolipid cleavage provided superiority over cholesterol depletion, and this method can open novel possibilities in the management of different pain conditions.

Duloxetine and cognitive behavioral therapy with phone-based support for the treatment of chronic musculoskeletal pain: study protocol of the PRECICE randomized control trial.

BACKGROUND: Chronic musculoskeletal pain (CMP) is the most common, disabling, and costly of all pain conditions. While evidence exists for the efficacy of both duloxetine and web-based cognitive behavioral therapy (CBT) as monotherapy, there is a clear need to consider study of treatment components that may complement each other. In addition, given the reported association between patient's adherence and treatment outcomes, strategies are needed to enhance participant's motivation to adopt and maintain continued use of newly learned pain coping skills from CBT. METHODS: Two hundred eighty participants will be recruited from the primary care clinics of a large academic health care system in North Carolina. Participants with CMP will be randomized to one of three treatment arms: (1) combination treatment (duloxetine + web-based self-guided CBT) with phone-based motivational interviewing (MI), (2) combination treatment without phone-based MI, and (3) duloxetine monotherapy. Participants will be in the study for 24 weeks and will be assessed at baseline, week 13, and week 25. The primary outcome is the Brief Pain Inventory (BPI)-Global Pain Severity score, which combines BPI pain severity and BPI pain interference. Secondary measures include between-group comparisons in mean BPI pain severity and BPI pain interference scores. Data collection and outcome assessment will be blinded to treatment group assignment. DISCUSSION: This randomized controlled trial (RCT) will determine if combination treatment with duloxetine and web-based CBT is superior to duloxetine monotherapy for the management of CMP. Furthermore, this RCT will determine the effectiveness of phone-based motivational interviewing in promoting the continued practice of pain coping skills, thereby enhancing treatment outcomes. TRIAL REGISTRATION: NCT04395001 ClinicalTrials.gov. Registered on May 15, 2020.

Hyperbaric oxygen therapy vs. pharmacological intervention in adults with fibromyalgia related to childhood sexual abuse: prospective, randomized clinical trial.

Fibromyalgia syndrome (FMS) is a chronic pain syndrome characterized by disruptions in pain processing within the central nervous system. It exhibits a high prevalence among patients with a history of traumatic experiences, notably childhood sexual abuse (CSA). This study compared the efficacy of hyperbaric oxygen therapy (HBOT) to the current pharmacological standard of care for individuals suffering from CSA-related FMS. Forty-eight participants diagnosed with FMS and a history of CSA were randomly assigned to either the HBOT group (60 sessions of 100% oxygen at 2 ATA for 90 min, with air breaks every 5 min) or the medication (MED) group (FDA-approved medications, Pregabalin and Duloxetine). The primary endpoint was the Fibromyalgia impact questionnaire (FIQ) score, while secondary endpoints encompassed emotional status and daily functioning questionnaires, as well as pain thresholds and conditioned pain modulation tests. Brain activity was evaluated through single photon emission computed tomography (SPECT). Results revealed a significant group-by-time interaction for the FIQ score favoring HBOT over MED (p < 0.001), with a large effect size (Cohen's d = - 1.27). Similar findings were observed in emotional symptoms and functional measures. SPECT imaging demonstrated an increase in activity in pre-frontal and temporal brain areas, which correlated with symptoms improvement. In conclusion, HBOT exhibited superior benefits over medications in terms of physical, functional, and emotional improvements among FMS patients with a history of CSA. This associated with increased activity in pre-frontal and temporal brain areas, highlighting the neuroplasticity effect of HBOT.

Mechanisms and Preventative Strategies for Persistent Pain following Knee and Hip Joint Replacement Surgery: A Narrative Review.

Chronic postsurgical pain (CPSP) following total knee arthroplasty (TKA) and total hip arthroplasty (THA) is a prevalent complication of joint replacement surgery which has the potential to decrease patient satisfaction, increase financial burden, and lead to long-term disability. The identification of risk factors for CPSP following TKA and THA is challenging but essential for targeted preventative therapy. Recent meta-analyses and individual studies highlight associations between elevated state anxiety, depression scores, preoperative pain, diabetes, sleep disturbances, and various other factors with an increased risk of CPSP, with differences observed in prevalence between TKA and THA. While the etiology of CPSP is not fully understood, several factors such as chronic inflammation and preoperative central sensitization have been identified. Other potential mechanisms include genetic factors (e.g., catechol-O-methyltransferase (COMT) and potassium inwardly rectifying channel subfamily J member 6 (KCNJ6) genes), lipid markers, and psychological risk factors (anxiety and depression). With regards to therapeutics and prevention, multimodal pharmacological analgesia, emphasizing nonopioid analgesics like acetaminophen and non-steroidal anti-inflammatory drugs (NSAIDs), has gained prominence over epidural analgesia. Nerve blocks and local infiltrative anesthesia have shown mixed results in preventing CPSP. Ketamine, an N-methyl-D-aspartate (NMDA)-receptor antagonist, exhibits antihyperalgesic properties, but its efficacy in reducing CPSP is inconclusive. Lidocaine, an amide-type local anesthetic, shows tentative positive effects on CPSP. Selective serotonin reuptake inhibitors (SSRIs) and serotonin norepinephrine reuptake inhibitors (SNRIs) have mixed results, while gabapentinoids, like gabapentin and pregabalin, present hopeful data but require further research, especially in the context of TKA and THA, to justify their use for CPSP prevention.

The Effect of Melatonin on Reducing the Frequency and Severity of Migraine Attacks: A Double-Blind, Randomized Clinical Trial.

Background: There is no definite recommendation for melatonin supplementation in episodic migraine. This study aimed to evaluate the effect of melatonin on reducing the frequency and severity of migraine attacks. Methods: This randomized, double-blind clinical trial was conducted at Golestan Hospital of Ahvaz, Iran, in 2021. A total of 60 patients with episodic migraine were randomly assigned into 2 groups of receiving 3 mg melatonin (intervention group; n=30) or the same dose of placebo (control group; n=30) along with baseline therapy (propranolol 20 mg, BID) for two months. The attack frequency, attack duration, attack severity (based on VAS), the number of analgesic intakes, drug complications, Migraine Disability Assessment score (MIDAS), and Pittsburgh sleep quality index (PSQI) were evaluated at baseline and in the first, second, third, and fourth months of follow-up. The independent t test, chi-square, and analysis of variance (ANOVA) with repeated measures were used to compare variables between the two groups. Results: In both groups, the frequency, duration, and severity of attacks, taking analgesics, MIDAS, and PSQI scores during follow-up decreased significantly (P<0.001). After treatment, the mean frequency (P=0.032) and duration of attacks (P=0.001), taking analgesic (P<0.001), and MIDAS (P<0.001) and PSQI scores (P<0.001) in the melatonin group were lower than placebo. Only the attack severity was not significantly different between the two groups (P=0.126). Side effects were observed in two patients (6.7%) in the melatonin group and one patient (3.3%) in the placebo group (P>0.999). Conclusion: Our study shows that melatonin was more efficacious than the placebo in the reduction of frequency and duration of migraine attacks. It was equally safe as the placebo and might be effective in the preventive treatment of episodic migraine in adults.Trial Registration Number: IRCT20190107042264N5.

Associations between over-the-counter analgesics usage and symptoms of anxiety and depression in adolescents: a network analysis.

BACKGROUND: The use of over-the-counter analgesics (OTCA) is common among adolescents and has been linked with increased symptoms of anxiety and depression. However, little is known about which specific symptoms are most strongly connected to OTCA usage. The current study assessed which anxiety and depression symptoms were most closely associated with OTCA usage in a large sample of adolescents and examined whether this differed across genders. METHOD: The present study was based on data from 626,581 participants from the Ungdata survey in Norway. Associations between OTCA and anxiety and depression symptoms were examined using network analysis. Non-regularized partial-correlation networks were constructed to estimate the conditional dependent relations between the use of OTCA and symptoms while controlling for pain. Gender-specific networks were created for comparison. RESULTS: OTCA usage was associated with most symptoms, even after controlling for pain, with the strongest associations with "sleep problems", "stiff or tense", "everything is a struggle" and "suddenly scared". There were some gender differences, showing that "sleep problems" and "hopeless" were more strongly related to OTCA usage in females, whereas "stiff or tense" was more strongly related to OTCA usage in males. CONCLUSION: Overall, the somatic symptoms of anxiety and depression displayed the strongest associations with OTCA usage. When examining the gender-specific networks, both showed similar trends, although males exhibited slightly stronger associations between OTCA usage and somatic symptoms.

Analgesia for the treatment of acute pancreatitis: a protocol for a systematic review and network meta-analysis.

INTRODUCTION: Gastrointestinal hospitalisations in the USA cause over US$130 billion in expenditures, and acute pancreatitis is a leading cause of these hospitalisations. Adequate pain control is one of the primary treatment goals for acute pancreatitis. Though opioids are commonly used for analgesia in these patients, there have been concerns about short-term and long-term side effects of using opioids. Recently, non-opioid medications have been studied to treat pain in patients with acute pancreatitis. This systematic review and network meta-analysis aims to assess the comparative efficacy of analgesic medication for non-severe, acute pancreatitis. METHODS AND ANALYSIS: We will search multiple electronic databases for randomised controlled trials that study pain management in patients with non-severe, acute pancreatitis. The intervention will be any analgesic for acute pancreatitis in the hospital setting. The comparison group will be patients who received a placebo or other active interventions for pain management. The primary outcomes of interest include pain scores and the need for supplementary analgesia. The secondary outcomes will be serious adverse events, local complications, progression to severe pancreatitis, transfer to the intensive care unit, length of hospitalisation, time to start enteral feeds, 30-day all-cause mortality and Quality of Life Scale scores. If sufficient homogeneity exists among included studies, the findings will be pooled using a traditional pairwise and network meta-analysis. The risk of bias in randomised control trials will be evaluated using the Cochrane Risk of Bias Tool 2.0. The Grading of Recommendations, Assessment, Development, and Evaluation approach will be used to report the certainty of evidence. ETHICS AND DISSEMINATION: This systematic review will not involve direct contact with human subjects. The findings of this review will be published in a peer-reviewed journal. They will give healthcare providers a better awareness of the optimal analgesic medication for pain treatment in non-severe, acute pancreatitis.

Cannabis medicine for chronic pain.

In the last decade, patients with chronic pain have expressed increasing interest in cannabis-derived products for adjuvant therapy when treatment is deemed refractory to conventional analgesics. At present, clinical evidence to support this treatment approach appears to be sparse. Not because clinical studies as such are lacking, but rather as a result of methodological bias in relation to study design, patient populations, and treatment protocols. In this review, research in cannabis medicine for relief of chronic pain is reviewed, mainly with reference to published meta-analytic studies.

Neuropathic pain in cats: Mechanisms and multimodal management.

PRACTICAL RELEVANCE: Chronic pain is a significant welfare concern in cats, and neuropathic pain, which arises from aberrant processing of sensory signals within the nervous system, is a subcategory of this type of pain. To comprehend this condition and how multimodal pharmacotherapy plays a central role in alleviating discomfort, it is crucial to delve into the anatomy of nociception and pain perception. In addition, there is an intricate interplay between emotional health and chronic pain in cats, and understanding and addressing the emotional factors that contribute to pain perception, and vice versa, is essential for comprehensive care.Clinical approach:Neuropathic pain is suspected if there is abnormal sensation in the area of the distribution of pain, together with a positive response to trial treatment with drugs effective for neuropathic pain. Ideally, this clinical suspicion would be supported by confirmation of a lesion at this neurolocalisation using diagnostic modalities such as MRI and neuroelectrophysiology. Alternatively, there may be a history of known trauma at that site. A variety of therapies, including analgesic, anti-inflammatory and adjuvant drugs, and neuromodulation (eg, TENS or acupuncture), can be employed to address different facets of pain pathways.Aim:This review article, aimed at primary care/ general practitioners, focuses on the identification and management of neuropathic pain in cats. Three case vignettes are included and a structured treatment algorithm is presented to guide veterinarians in tailoring interventions.Evidence base:The review draws on current literature, where available, along with the author's extensive experience and research.

Evaluation of the effects of pregabalin and dexamethasone coadministration on preemptive multimodal analgesia and anxiety in third molar surgeries: a triple-blind randomized clinical trial.

OBJECTIVE: To evaluate the efficacy of pregabalin and dexamethasone coadministration in preemptive analgesia and anxiety control in lower third molar surgery. MATERIALS AND METHODS: A triple-blind, split-mouth clinical trial conducted with patients divided into two groups: control group, receiving placebo and dexamethasone, and test group, receiving pregabalin and dexamethasone preoperatively. The evaluated variables were pain, measured by the Visual Analog Scale (VAS), anxiety assessed through the State-Trait Anxiety Inventory (STAI) questionnaires, hemodynamic parameters [Blood Pressure (BP), Heart Rate (HR), Oxygen Saturation (SpO2)], and sedation assessed by the Ramsay scale. RESULTS: A total of 31 patients were included. The test group exhibited a significant reduction in pain at 2,4,6,8,12,16,24, and 48 h after surgery and in the consumption of rescue analgesics. Anxiety, evaluated by STAI and VAS, showed a significant decrease in the test group (p < 0.001). Additionally, there was a significant decrease in BP at most of the assessed time points (p < 0.05) and a significant reduction in HR at two different time intervals (p = 0.003 and p = 0.009), indicating a positive effect in the test group. There was no significant difference in SpO2 between the groups. Sedation assessment revealed a significant difference at all time points favoring the test group (p < 0.05). There were no significant postoperative adverse effects. CONCLUSIONS: Pregabalin coadministered with dexamethasone demonstrated significant efficacy in controlling postoperative pain and anxiety, as well as a sedative effect. CLINICAL RELEVANCE: The coadministration of pregabalin with dexamethasone may presents potential advantages in both pain modulation and psychological well-being of individuals undergoing third molar surgeries. TRIAL REGISTRATION: Brazilian Clinical Trials Registry (REBEC), No. RBR-378h6t6.

The relationship of depressive symptoms with pain and analgesic use in Turkish adolescents.

PROBLEM: This study aimed to determine the prevalence of depressive symptoms, pain (headache, abdominal pain, back pain) and analgesic use among Turkish adolescents. Additionally, it aimed to examine the association between depressive symptoms and pain and analgesic use in adolescents. METHODS: This cross-sectional, correlational study was conducted in Izmir, Turkey with 954 adolescents aged 11-19 years. Data were collected with the "socio-demographic questionnaires" and the "Center for Epidemiologic Studies Depression Scale for Children". Analyzes were performed using descriptive statistics and multiple logistic regression analysis. FINDINGS: Of the adolescents, 632 (66.2%) showed depressive symptoms. Of the adolescents, 424 (44.4%) experienced headache, 256 (26.8%) experienced abdominal pain, and 343 (36.0%) experienced back pain. A total of 309 (32.4%) adolescents used analgesics for headaches, 132 (13.8%) abdominal pain, and 47 (4.9%) for back pain. Female gender, high level maternal education, bad economic status, poor health perception, bad school success, pain and analgesic use were the correlated variables with adolescent depression. CONCLUSIONS: The depressive symptoms, headache and back pain, and use of analgesics especially for headaches were common among adolescents. The results showed depression in adolescent correlated with pain (headache, abdominal pain, and back pain) and analgesic use. Regular screening is needed to assure early intervention of depression among adolescents.

Analgesic Peptides: From Natural Diversity to Rational Design.

Pain affects one-third of the global population and is a significant public health issue. The use of opioid drugs, which are the strongest painkillers, is associated with several side effects, such as tolerance, addiction, overdose, and even death. An increasing demand for novel, safer analgesic agents is a driving force for exploring natural sources of bioactive peptides with antinociceptive activity. Since the G protein-coupled receptors (GPCRs) play a crucial role in pain modulation, the discovery of new peptide ligands for GPCRs is a significant challenge for novel drug development. The aim of this review is to present peptides of human and animal origin with antinociceptive potential and to show the possibilities of their modification, as well as the design of novel structures. The study presents the current knowledge on structure-activity relationship in the design of peptide-based biomimetic compounds, the modification strategies directed at increasing the antinociceptive activity, and improvement of metabolic stability and pharmacodynamic profile. The procedures employed in prolonged drug delivery of emerging compounds are also discussed. The work summarizes the conditions leading to the development of potential morphine replacements.

A comparative study on prophylactic efficacy of cinnarizine and amitriptyline in childhood migraine: a randomized double-blind clinical trial.

BACKGROUND: Pediatric migraine prophylaxis is indicated when headaches are frequent and/or disabling. We aimed to conduct a study to compare the efficacy of cinnarizine and amitriptyline in pediatric migraine prophylaxis. METHODS: In a randomized, double-blind trial, patients aged 4-17 years with migraine who were eligible for prophylaxis enrolled. The primary outcome was a reduction response rate of ≥50% with p < 0.005 with respect to headache characteristics. The secondary outcome was migraine disability assessment. We evaluated patients every four weeks for three months: T1: week 4, T2: week 8 and T3: week 12. The safety profile was also assessed. RESULTS: Thirty patients were randomly assigned to each group. However, 43 patients completed the trial. Headache frequency decreased in amitriptyline group more effectively in T1 (p = 0.004). Amitriptyline was more successful in reducing the headache duration in all three periods (p < 0.005). There was no significant difference in severity improvement and reducing disability score between the two groups (p > 0.005). No serious adverse events were observed. CONCLUSIONS: Both medications are effective in ameliorating migraine headaches and related disabilities. However, amitriptyline appears be a preferable option over cinnarizine, given its faster onset of action, efficacy in reducing headache duration and longer-lasting effects.Trial Registration: The study was registered with the Iranian Registry of Clinical Trials (IRCT) under the code IRCT-20191112045413N1.

The impact of perioperative ketamine or esketamine on the subjective quality of recovery after surgery: a meta-analysis of randomised controlled trials.

BACKGROUND: This meta-analysis aimed to evaluate the impact of ketamine/esketamine on postoperative subjective quality of recovery (QoR). METHODS: MEDLINE, Embase, Cochrane library, and Google Scholar were searched for randomised controlled trials (RCTs) that examined the impacts of perioperative ketamine/esketamine use and postoperative QoR. The primary outcome was subjective QoR (QoR-9, QoR-15, QoR-40) on postoperative day (POD) 1-3, whereas the secondary outcomes included pain severity, anxiety scores, depression scores, risk of adverse events (i.e. nausea, vomiting, dizziness, drowsiness), and length of stay. RESULTS: The analysis included 18 RCTs (1554 participants; ketamine: seven trials, esketamine: 11 trials), of which 15 were conducted in China. Ketamine/esketamine improved the QoR scores on PODs 1 and 2 compared with the control (standardised mean difference [SMD]: 0.63, P<0.0001 for POD 1; SMD: 0.56, P=0.04 for POD 2), without beneficial effect on POD 3. Subgroup analyses revealed significant differences in QoR scores on POD 1 by regimen (SMD: esketamine 1.14, ketamine 0.01) and country (SMD: China 0.82, other countries -0.21). The emotional domain of QoR was improved from PODs 1 to 3, whereas the other domains were only improved on POD 1. Lower postoperative anxiety (SMD: -0.48, P=0.003) and depression (SMD: -0.72, P=0.001) scores were also observed with ketamine/esketamine use. Furthermore, pain severity was reduced on PODs 1 and 2, with no difference in the risk of adverse events or length of stay. CONCLUSIONS: This meta-analysis demonstrated that ketamine/esketamine use in the perioperative period is associated with improved early subjective QoR, pain severity, and psychological symptoms without an increase in the likelihood of adverse events. SYSTEMATIC REVIEW PROTOCOL: PROSPERO (CRD42023477580).

Modeling an evaluation of the efficacy of the novel neuroanalgesic drug mirogabalin for diabetic peripheral neuropathic pain and postherpetic neuralgia therapy.

Diabetic peripheral neuropathic pain (DPNP) and postherpetic neuralgia (PHN) are challenging and often intractable complex medical conditions, with a substantial impact on the quality of life. Mirogabalin, a novel voltage-gated Ca2+ channel α2δ ligand, was approved for the indication of DPNP and PHN. However, the time course of effects has not yet been clarified.We aimed to establish pharmacodynamic and placebo effect models of mirogabalin and pregabalin in DPNP and PHN, and to quantitatively compare the efficacy characteristics (maximum efficacy, onset time, and other pharmacodynamic parameters) and safety of mirogabalin and pregabalin. Public databases were comprehensively searched for randomized placebo-controlled clinical trials. A model-based meta-analysis (MBMA) was developed to describe the time course of drug efficacy and placebo effects. Adverse events were compared using a fixed-effects meta-analysis. Sixteen studies including 5,147 participants were eligible for this study. The placebo effect was relatively high and gradually increased with time, and it required at least eight weeks to reach a plateau. The pharmacodynamic model revealed that the maximum pure efficacy for mirogabalin and pregabalin was approximately -7.85 % and -8.86 %, respectively; the efficacy of mirogabalin to relieve DPNP and PHN was not superior to that of pregabalin, and both drugs had similar safety. While the rate constant of the onset rate of pregabalin was approximately thrice as high as that of mirogabalin. In addition, the baseline level of pain was an important factor affecting pregabalin efficacy. These findings are helpful in evaluating the clinical extension value of mirogabalin. They suggest that the high placebo effect and the baseline level of pain should be considered when grouping patients in future research and development of voltage-gated Ca2+ channel neuroanalgesic.

Study on analgesic effect of Shentong Zhuyu Decoction in neuropathic pain rats by network pharmacology and RNA-Seq.

ETHNOPHARMACOLOGICAL RELEVANCE: Shentong Zhuyu Decoction (STZYD) is a traditional prescription for promoting the flow of Qi and Blood which is often used in the treatment of low back and leg pain clinicall with unclear mechanism. Neuropathic pain (NP) is caused by disease or injury affecting the somatosensory system. LncRNAs may play a key role in NP by regulating the expression of pain-related genes through binding mRNAs or miRNAs sponge mechanisms. AIM OF THE STUDY: To investigate the effect and potential mechanism of STZYD on neuropathic pain. METHODS: Chronic constriction injury (CCI) rats, a commonly used animal model, were used in this study. The target of STZYD in NP was analyzed by network pharmacology, and the analgesic effect of STZYD in different doses (H-STZYD, M-STZYD, L-STZYD) on CCI rats was evaluated by Mechanical withdrawal thresholds (MWT) and thermal withdrawal latency (TWL). Meanwhile, RNA-seq assay was used to detect the changed mRNAs and lncRNAs in CCI rats after STZYD intervention. GO analysis, KEGG pathway analysis, and IPA analysis were used to find key target genes and pathways, verified by qPCR and Western Blot. The regulatory effect of lncRNAs on target genes was predicted by co-expression analysis and ceRNA network construction. RESULTS: We found that STZYD can improve hyperalgesia in CCI rats, and H-STZYD has the best analgesic effect. The results of network pharmacological analysis showed that STZYD could play an analgesic role in CCI rats through the MAPK/ERK/c-FOS pathway. By mRNA-seq and lncRNA-seq, we found that STZYD could regulate the expression of Cnr1, Cacng5, Gucy1a3, Kitlg, Npy2r, and Grm8, and inhibited the phosphorylation level of ERK in the spinal cord of CCI rats. A total of 27 lncRNAs were associated with the target genes and 30 lncRNAs, 83 miRNAs and 5 mRNAs participated in the ceRNA network. CONCLUSION: STZYD has the effect of improving hyperalgesia in CCI rats through the MAPK/ERK/c-FOS pathway, which is related to the regulation of lncRNAs to Cnr1 and other key targets.