Study of the preparation, characterization, and solubility of lidocaine complexed with 5-sulfosalicylic acid dihydrate

OBJECTIVE

This study was to prepare solid dispersions of lidocaine (Lid) with 5-sulfosalicylic acid dihydrate (SSA) by freeze-drying (freeze-dried [FD] Lid/SSA = 1/1) and to evaluate their physical properties.

METHODS

Here, we evaluated the physicochemical properties and solubility of solid dispersions of Lid and SSA prepared by freeze-drying (freeze-dried [FD] Lid/SSA = 1/1).

RESULTS

Differential scanning calorimetry measurements showed that after freeze-drying, the endothermic peak due to Lid melting, the dehydration peak, and the endothermic peak due to SSA melting disappeared. Powder X-ray diffraction results showed that the characteristic Lid and SSA peaks disappeared after freeze-drying, indicating a halo pattern. The near-infrared spectroscopy results suggested that Lid-derived -NH and -CH groups and the Lid-derived -OH and -CH groups from the SSA peak shifted and broadened after freeze-drying, suggesting their involvement in complex formation through Lid/SSA intermolecular interactions. Nuclear Overhauser effect spectroscopy-nuclear magnetic resonance (NMR) measurements showed a cross-peak due to the interaction between the Lid-derived -CH group and the SSA-derived -OH group, suggesting hydrogen bonding. Diffusion-ordered spectroscopy NMR measurements showed that the diffusion coefficients of Lid and SSA aggregated in FD Lid/SSA, suggesting a change in Lid dispersibility in the solvent owing to the formation of a complex with SSA. The solubility of FD Lid/SSA was approximately 88 mg/mL (∼20-fold higher than that of Lid).

CONCLUSIONS

These findings suggest that complex formation occurred in FD Lid/SSA; this enhanced the solubility of this dispersion.

SUNCT, SUNA and short-lasting unilateral neuralgiform headache attacks: Debates and an update

BACKGROUND

Short-lasting unilateral neuralgiform headache attacks (SUNHA) have the features of both short-lasting unilateral neuralgiform pain, such as trigeminal neuralgia or stabbing headache, and associated trigeminal autonomic symptoms, such as paroxysmal hemicrania or cluster headache. Recognizing and adequately treating SUNHA is essential but current treatment methods are ineffective in treating SUNHA.

METHODS

We reviewed the changes in the concept of short-lasting unilateral neuralgiform headache attacks and provide a narrative review of the current medical and surgical treatment options, from the first choice of treatment for patients to treatments for selective intractable cases.

RESULTS

Unlike the initial impression of an intractable primary headache disorder affecting older men, SUNHA affects both sexes throughout their lifespan. One striking feature of SUNHA is that the attacks are triggered by cutaneous or intraoral stimulation. The efficacy of conventional treatments is disappointing and challenging, and preventive therapy is the mainstay of treatment because of highly frequent attacks of a very brief duration. Amongst them, lamotrigine is effective in approximately two-third of the patients with SUNHA, and intravenous lidocaine is essential for the management of acute exacerbation of intractable pain. Topiramate, oxcarbazepine and gabapentin are considered good secondary options for SUNHA, and botulinum toxin can be used in selective cases. Neurovascular compression is commonly observed in SUNHA, and surgical approaches, such as neurovascular compression, have been reported to be effective for intractable cases.

CONCLUSIONS

Recent advances in the understanding of SUNHA have improved the recognition and treatment approaches for this unique condition.

Lidocaine infusion for malignant visceral pain: case report

BACKGROUND

Visceral pain accounts for nearly 28% of cancer-related pain, and its effective management poses significant challenges. The diverse pathways of neurotransmission, neurotransmitters, channels, and receptors suggest the need for individualized analgesic therapy. Our objective is to explore a therapeutic alternative for managing malignant visceral pain in advanced cancer.

CASES

In this report, we present two patients with malignant bowel obstruction and severe visceral pain, despite receiving opioid treatment, necessitating an alternative approach. Surgical interventions were considered but promptly ruled out. Paracentesis was performed as necessary. Pain management was initiated using a combination of opioids and co-analgesics. However, both patients required opioid dose escalation without achieving adequate pain control or tolerating the associated side effects. Consequently, a lidocaine infusion was administered to alleviate pain.

OUTCOME

Following 24-48 hours of lidocaine infusion, both patients achieved satisfactory symptom control, enabling a reduction in opioid doses and improvement in intestinal transit. No side effects were reported during the treatment.

DISCUSSION

Lidocaine infusions may be beneficial for pain management in patients with malignant bowel obstruction and visceral pain. The extent of pain control achieved in comparison to other therapeutics remains challenging to ascertain. We posit that lidocaine infusions, with their potential impact on visceral hypersensitivity, can enhance pain control and facilitate the recovery of bowel transit. Further studies are warranted to validate these findings.

Lidocaine ameliorates intestinal barrier dysfunction in irritable bowel syndrome by modulating corticotropin-releasing hormone receptor 2

BACKGROUND

Intestinal barrier dysfunction is a prevalent pathogenic factor underlying various disorders. Currently there is no effective resolution. Previous studies have reported the potential anti-inflammatory properties of lidocaine and its ability to alleviate visceral hypersensitivity in individuals with irritable bowel syndrome (IBS). Therefore, our study will further verify the effect of lidocaine on intestinal barrier dysfunction in IBS and investigate the underlying mechanisms.

METHODS

In this study, we investigated the role of lidocaine by assessing visceral hypersensitivity, body weight, inflammatory factors, fluorescein isothiocyanate-dextran 4000 (FD4) flux, tight junctions (TJs) and spleen and thymus index in rats subjected to water avoidance stress (WAS) to mimic intestinal barrier dysfunction in IBS with and without lidocaine. In vitro, we investigated the role of corticotropin-releasing hormone receptor 2 (CRHR2) in lidocaine-treated Caco2 cells using small interfering RNA (siRNA) targeting CRHR2.

KEY RESULTS

In WAS rats, lidocaine significantly restored weight loss, damaged TJs, spleen index and thymus index and inhibited abdominal hypersensitivity as well as blood levels of markers indicating intestinal permeability, such as diamine oxidase (DAO), D-lactic acid (D-Lac) and lipopolysaccharide (LPS). Consequently, the leakage of FD4 flux from intestine was significantly attenuated in lidocaine group, and levels of intestinal inflammatory factors (IL-1β, IFN-γ, TNF-α) were reduced. Interestingly, lidocaine significantly suppressed corticotropin-releasing hormone (CRH) levels in lamina propria cells, while the CRH receptor CRHR2 was upregulated in intestinal epithelial cells. In vitro, lidocaine enhanced the expression of CRHR2 on Caco-2 intestinal epithelial cells and restored disrupted TJs and the epithelial barrier caused by LPS. Conversely, these effects were diminished by a CRHR2 antagonist and siRNA-CRHR2, suggesting that the protective effect of lidocaine depends on CRHR2.

CONCLUSIONS AND INFERENCES

Lidocaine ameliorates intestinal barrier dysfunction in IBS by potentially modulating the expression of CRHR2 on intestinal epithelial cells.

Lidocaine aerosol preoperative application for improving the comfort of pediatric patients undergoing tonsillectomy and adenoidectomy: A prospective randomized controlled trial

Background and Aims

The use of lidocaine aerosol for pediatric tonsil and adenoidectomy has been reported less frequently. We hope to improve the perioperative comfort of pediatric patients undergoing these procedures by applying lidocaine aerosol.

Methods

A total of 122 pediatric patients receiving tonsil and adenoidectomy were randomly divided into a lidocaine aerosol group (Group L) and a saline group (Group C), with 61 patients in each group; 2.4% alkaline lidocaine aerosol and saline were sprayed in the pharynx before induction. Our primary outcome were the incidence and rate ratio (RR) of postoperative pharyngeal complications (oropharyngeal dryness, dysphagia, hoarseness, and sore throat) and the pharyngeal comfort score, the latter of which was assessed by the occurrence of the above complications (yes = 0 point, none = 1 point). The secondary outcomes included preoperative and intraoperative blood pressure and heart rate, the incidence of choking during the induction period, the intraoperative opioid dosage, and the pain level and depth of sedation at 2, 6, and 24 h postoperatively. Statistical software used in this study included PASS15.0, SPSS 26.0, and GraphPad Prism 9.3.1, and statistical methods used included the t-test, the χ² test, the Mann-Whitney U test, and the repeated measures analysis of variance.

Results

The incidence and RR of postoperative pharyngeal complications such as oropharyngeal dryness (RR: 0.667, 95% confidence interval [CI]: 0.458-0.970, p = 0.03), dysphagia (RR: 0.333, 95% CI: 0.114-0.976, p = 0.03), hoarseness (RR: 0.647, 95% CI: 0.433-0.967, p = 0.03), and sore throat (RR: 0.727, 95% CI: 0.547-0.967, p = 0.03) were significantly lower in Group L than in Group C at 2 h postoperatively, and the incidence and RR of postoperative sore throat was significantly lower in Group L than in Group C at 6 h postoperatively (RR: 0.717, 95% CI: 0.547-0.942, p = 0.01). The postoperative pharyngeal comfort scores were significantly higher in Group L than in Group C at all postoperative time points (p < 0.05). The Ramsay sedation score was significantly higher (p < 0.01) and FLACC (face, legs, activity, crying, and consolability) score was significantly lower (p < 0.01) in Group L than in Group C at 2 h postoperatively. In Group C, the blood pressure and heart rate significantly faster at all time points immediately after intubation and afterward, except at the end of surgery (p < 0.05).

Conclusions

In pediatric tonsil and adenoidectomy, the application of lidocaine aerosol before induction can reduce the incidence of postoperative pharyngeal complications, improve the child's postoperative pharyngeal comfort, and better realize perioperative "comfort medical treatment."

Mechanism-Based Pharmacological Treatment for Chronic Non-cancer Pain in Adolescents: Current Approaches and Future Directions

Chronic non-cancer pain in pediatrics is a widespread phenomenon that affects about 20% of adolescents (10-19 years old). Although interdisciplinary pain treatment programs, which often include pharmacological treatment, have emerged as the standard of care in management of this patient population, evidence regarding an optimal treatment is lacking. The efficacy and safety profiles of pharmacological treatments used to help adolescents suffering from chronic non-cancer pain remain understudied. This lack of evidence may increase polypharmacy and the risk of drug interactions and adverse events. This review examines evidence for the use of pharmacological treatments prescribed to treat chronic pain in adolescents (10-19 years old), with a focus on mechanism-based pharmacology. The objectives of this review are to: (a) review the evidence for mechanism-based pharmacological treatments for chronic non-cancer pain in adolescents and (b) describe the pharmacological agents that are commonly prescribed to manage chronic pain in adolescents, including dosage information, mechanism, and potential adverse effects. Pharmacological treatments should be used carefully with adolescents, ideally within an interdisciplinary treatment program that will incorporate physical rehabilitation, integrative medicine/active mind-body techniques, psychology, and global efforts to normalize daily activities.

Lidocaine inhibits the proliferation and migration of endometrial cancer cells, and promotes apoptosis by inducing autophagy

As a gynecological malignancy, endometrial cancer (EC) has a high incidence and mortality rate in women. The aim of the present study was to investigate the mechanism of EC and to identify novel effective treatment methods for this disease. The viability and proliferation of the RL95-2 human endometrial cancer cell line were assessed using Cell Counting Kit-8 assays. Colony formation, wound healing, Transwell, TUNEL and immunofluorescence assays were used to assess the effects of 5, 10 and 15 mM lidocaine on the colony formation, migration, invasiveness, apoptosis and Beclin 1 protein expression of RL95-2 cells, respectively. Furthermore, western blotting was used to analyze the protein expression levels of apoptosis- and autophagy-related proteins. The results demonstrated that lidocaine inhibited the viability, proliferation and migration of EC cells, and promoted apoptosis. Furthermore, lidocaine was demonstrated to induce autophagy and Beclin 1 protein expression in EC cells. In conclusion, lidocaine inhibited the proliferation and migration of EC cells, and promoted apoptosis via autophagy induction, which indicated that lidocaine may be a potential therapeutic drug for the treatment of EC.

Lidocaine infusions for refractory chronic migraine: a retrospective analysis

Introduction

Patients with refractory chronic migraine have poor quality of life. Intravenous infusions are indicated to rapidly ‘break the cycle’ of pain. Lidocaine infusions may be effective but evidence is limited.

Methods

The records of 832 hospital admissions involving continuous multiday lidocaine infusions for migraine were reviewed. All patients met criteria for refractory chronic migraine. During hospitalization, patients received additional migraine medications including ketorolac, magnesium, dihydroergotamine, methylprednisolone, and neuroleptics. The primary outcome was change in headache pain from baseline to hospital discharge. Secondary outcomes measured at the post-discharge office visit (25–65 days after treatment) included headache pain and the number of headache days, and percentage of sustained responders. Percentage of acute responders, plasma lidocaine levels, and adverse drug effects were also determined.

Results

In total, 609 patient admissions met criteria. The mean age was 46±14 years; 81.1% were female. Median pain rating decreased from baseline of 7.0 (5.0–8.0) to 1.0 (0.0–3.0) at end of hospitalization (p<0.001); 87.8% of patients were acute responders. Average pain (N=261) remained below baseline at office visit 1 (5.5 (4.0–7.0); p<0.001). Forty-three percent of patients were sustained responders at 1 month. Headache days (N=266) decreased from 26.8±3.9 at baseline to 22.5±8.3 at the post-discharge office visit (p<0.001). Nausea and vomiting were the most common adverse drug effects and all were mild.

Conclusion

Lidocaine infusions may be associated with short-term and medium-term pain relief in refractory chronic migraine. Prospective studies should confirm these results.

Intravenous Lidocaine and Ketamine Infusions for Headache Disorders: A Retrospective Cohort Study

Introduction

The use of lidocaine (lignocaine) and ketamine infusion in the inpatient treatment of patients with headache disorders is supported by small case series. We undertook a retrospective cohort study in order to assess the efficacy, duration and safety of lidocaine and ketamine infusions.

Methods

Patients admitted between 01/01/2018 and 31/07/2021 were identified by ICD code and electronic prescription. Efficacy of infusion was determined by reduction in visual analog score (VAS), and patient demographics were collected from review of the hospital electronic medical record.

Results

Through the study period, 83 infusions (50 lidocaine, 33 ketamine) were initiated for a headache disorder (77 migraine, three NDPH, two SUNCT, one cluster headache). In migraine, lidocaine infusion achieved a ≥50% reduction in pain in 51.1% over a mean 6.2 days (SD 2.4). Ketamine infusion was associated with a ≥50% reduction in pain in 34.4% over a mean 5.1 days (SD 1.5). Side effects were observed in 32 and 42.4% respectively. Infusion for medication overuse headache (MOH) led to successful withdrawal of analgesia in 61.1% of lidocaine, and 41.7% of ketamine infusions.

Conclusion

Lidocaine and ketamine infusions are an efficacious inpatient treatment for headache disorders, however associated with prolonged length-of-stay and possible side-effects.

Lidocaine attenuates hypoxia/reoxygenation‑induced inflammation, apoptosis and ferroptosis in lung epithelial cells by regulating the p38 MAPK pathway

Lung ischemia-reperfusion (I/R) injury poses a serious threat to human health, worldwide. The current study aimed to determine the role of lidocaine in A549 cells, in addition to the involvement of the p38 MAPK pathway. Oxygen deprivation/reoxygenation-induced A549 cells were utilized to simulate I/R injury in vitro. Cell viability and apoptosis were detected using MTT and TUNEL assays, respectively. The levels of IL-6, IL-8, TNF-α, malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase, iron and reactive oxygen species (ROS) were measured using corresponding commercial kits. The corresponding protein expression levels were also measured using western blotting. Moreover, a monolayer cell paracellular permeability assay was performed to determine the permeability of A549 cells. The results demonstrated that, whilst lidocaine had no influence on untreated A549 cells, it significantly increased the viability of hypoxia/reoxygenation (H/R)-induced A549 cells. A549 cell apoptosis and the release of inflammatory cytokines in the H/R group were decreased after the addition of lidocaine. When compared with the H/R group, increased MDA level and decreased SOD level were observed in H/R-induced A549 cells following lidocaine treatment. In addition, the permeability of H/R-induced A549 cells was markedly decreased following lidocaine treatment. Compared with the H/R group, the expression levels of tight junction and ferroptosis-related proteins were significantly upregulated by lidocaine, whereas the expression of transferrin was downregulated. However, p79350, an agonist of p38, reversed the effects of lidocaine on H/R-induced A549 cells. In conclusion, lidocaine exerted a protective role in HR-induced lung epithelial cell injury, which may serve as a potential agent for the treatment of patients with lung I/R injury.

Patellar Tendinopathy: Critical Analysis Review of Current Nonoperative Treatments

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Patellar tendinopathy is an attritional injury of the patellar tendon that is frequently identified in jumping athletes. Through repetitive or explosive movements, considerable loads and high peak strains are generated across the patellar tendon.

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This leads to microinjury of tendon fibers, local mucoid degeneration, and loss of the fibrocartilaginous tissue that attaches tendon to bone.

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Management of patellar tendinopathy often begins with nonoperative modalities: progressive tendon loading and eccentric rehabilitative exercise programs are the most effective. While a variety of additional treatment modalities are available, the comparative efficacy of these supportive treatments is not well differentiated at this time.

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In this article, we analyze the existing literature regarding nonoperative treatment of patellar tendinopathy and provide additional insight on the effectiveness of current modalities.

Lidocaine relieves spinal cord ischemia-reperfusion injury via long non-coding RNA MIAT-mediated Notch1 downregulation

Microglial activation and inflammatory response play a critical role in spinal cord ischemia-reperfusion injury (SCIRI). This study aimed to investigate whether lidocaine relieves SCIRI via modulating MIAT-mediated Notch1 downregulation. Mouse SCIRI was induced by the obstruction of the aortic arch. Lidocaine was injected after reperfusion. Microglial activation and inflammatory response were assessed by Iba1, interleukin 1 beta (IL-1β), and tumor necrosis factor alpha (TNF-α) levels. The interaction between MIAT and Notch1 was assessed by RNA pull-down and RNA immunoprecipitation assays. Lidocaine treatment relieved SCIRI by reducing Iba1 and serum TNF-α and IL-1β levels. After lidocaine treatment, MIAT expression was elevated in lipopolysaccharide- (LPS-) induced BV2 cells. The interference of MIAT and the overexpression of MIAT and Notch1 restored TNF-α and IL-1β levels in supernatants. Notch1 protein was existent in MIAT-pull-down compounds, and the expression of MIAT was markedly elevated in Notch1-immunoprecipitants. The overexpression of MIAT markedly promoted the degradation of Notch1 and increased the level of ubiquitin-bound Notch1 complex. The therapeutic effect of lidocaine on SCIRI mice could be reversed by adeno-associated virus-mediated MIAT knockdown. In conclusion, lidocaine treatment relieved SCIRI via inhibiting microglial activation and reducing the inflammatory response. The molecular mechanism was partly through MIAT-mediated Notch1 downregulation.

Beyond the Raskin Protocol: Ketamine, Lidocaine, and Other Therapies for Refractory Chronic Migraine

PURPOSE OF REVIEW

The purpose of this review is to discuss the available evidence and therapeutic considerations for intravenous drug therapy for refractory chronic migraine.

RECENT FINDINGS

In carefully monitored settings, the inpatient administration of intravenous lidocaine and ketamine can be successful in treating refractory chronic migraine. Many patients with refractory chronic migraine have experienced treatment failure with the Raskin protocol. The use of aggressive inpatient infusion therapy consisting of intravenous lidocaine or ketamine, along with other adjunctive medications, has become increasingly common for these patients when all other treatments have failed. There is a clear need for prospective studies in this population comprised of patients who have largely been excluded from other studies.

Efficacy of Perioperative Continuous Intravenous Lidocaine Infusion for 72 Hours on Postoperative Pain and Recovery in Patients Undergoing Hepatectomy: Study Protocol for a Prospective Randomized Controlled Trial

Purpose

Many patients develop severe and persistent pain after hepatectomy delaying postoperative rehabilitation. Studies have suggested that intravenous lidocaine infusion relieved postoperative pain and improved overall postoperative outcomes. However, its efficacy on hepatectomy is still masked, due to the postoperative metabolic change of lidocaine by the liver. We hypothesized that intravenous lidocaine infusion in the perioperative period would lead to postoperative pain reduction and improve the overall patient experience.

Study Design and Methods

In this prospective double-blind, randomized controlled design trial, 260 adults scheduled for hepatectomy will be allocated to the lidocaine and the placebo groups. The lidocaine group will be administered lidocaine intravenously during intraoperative period and 72 postoperative hours; the placebo group will be administered normal saline at the same volume, infusion rate, and timing. The primary outcome is the incidence of moderate-severe pain (numeric rating scale ≥4) during movement at 24 hours after surgery. The secondary outcomes include the incidence of moderate-severe pain at 24 hours after surgery at rest, the incidence of moderate-severe pain at 48 and 72 hours after surgery at rest and during movement, the cumulative morphine consumption at 24, 48 and 72 hours postoperatively, bowel function recovery, the incidence of postoperative nausea and vomiting, the incidence of postoperative pulmonary complications, the length of hospital stay, levels of inflammatory factors and patient satisfaction scores.

Discussion

This is the first prospective trial to shed light on the efficacy of intraoperative period and 72 postoperative hours intravenous lidocaine on postoperative pain and recovery after hepatectomy. The findings will provide a new strategy of perioperative pain management for hepatectomy.

Intravenous lidocaine vs. NSAIDs for migraine attack in the ED: a prospective, randomized, double-blind study

PURPOSE

Although different forms of lidocaine are used for migraine attack headaches, the effect of intravenous lidocaine is still limited. This study aimed to investigate the effects of intravenous lidocaine infusion for the treatment of migraine attack headaches.

METHODS

A hundred patients with migraine attacks, aged between 18 and 65, were randomly divided into two groups. The lidocaine group (n = 50) received a 1.5 mg/kg lidocaine bolus and a 1 mg/kg infusion (first 30 min), followed by a 0.5 mg/kg infusion for a further 30 min intravenously. The non-steroidal anti-inflammatory drug (NSAID) group (n = 50) received 50 mg dexketoprofen trometamol and saline at the same volume as the lidocaine at the same time intervals intravenously. The Visual Analog Scale (VAS) pain scores, additional analgesia requirement, side effects, and revisits to the emergency department were recorded.

RESULTS

The VAS score was significantly lower in the lidocaine group than in the NSAID group for the first 20th and 30th minutes (p = 0.014 and p = 0.024, respectively). There was no difference between the VAS scores for the remaining evaluation times (p > 0.05). In terms of secondary outcomes, rescue medication requirement was not different between the two groups at both the 60th and 90th minutes (p > 0.05). However, the number of patients revisiting ED within 48-72 h was statistically less in the lidocaine group than in the NSAID group (1/50 vs. 8/50; p = 0.031).

CONCLUSION

Intravenous lidocaine may be an alternative treatment method for patients with migraine attack headaches in the emergency department.

Continuous Intravenous Lidocaine Provides Effective Pain Control in a Palliative Child: A Case Report

Lidocaine infusion is often used as part of a perioperative, multimodal pain management plan. We present its use to treat an 8-year-old child with devastating headaches. His symptoms stemmed from an inoperable supratentorial ependymoma that was causing thalamic bleeding and increased intracranial pressure. Many commonly used pain medications are associated with deleterious side effects such as bleeding and excessive sedation. These effects prevent lucidity for interactions, confound neurologic examination. A lidocaine infusion resulted in significant pain relief without these negative side effects. We discuss lidocaine infusion use and considerations for children suffering from intractable headaches.

Lidocaine attenuates CFA-induced inflammatory pain in rats by regulating the MAPK/ERK/NF-κB signaling pathway

Lidocaine is a commonly used local anesthetic that also confers analgesic effects, resistance to hyperalgesia and anti-inflammatory properties. The present study aimed to explore the effects of lidocaine on complete Freund's adjuvant (CFA)-induced inflammatory pain. In the present study, rats were subcutaneously injected with CFA to investigate the molecular mechanisms associated with lidocaine in an inflammation-induced pain model. Firstly, CFA was subcutaneously injected into the paws of Sprague-Dawley rats, following which lidocaine or saline and the ERK agonist recombinant human epidermal growth factor (rh-EGF) were injected via the tail vein. Rat behavior was then assessed at 0 and 4 h, 1, 4, 7 and 14 days after CFA treatment. Proinflammatory cytokine levels in the serum were measured using ELISA. Western blotting was performed to detect the protein levels of phosphorylated (p)-ERK1/2, ERK1/2 and NF-κB subunits p-p65 and p65. Reverse transcription-quantitative PCR was used to measure the mRNA expression of ERK1/2 and p65 in rat spinal cord tissues. The results showed that injection of CFA significantly reduced the mechanical withdrawal threshold, thermal withdrawal latency and the frequency of responses to cold stimulation in rats, whilst promoting tumor necrosis factor-α, interleukin (IL)-1β, IL-6 levels in addition to ERK1/2, p65 protein phosphorylation. These effects were alleviated by lidocaine treatment. Furthermore, treatment with rh-EGF reversed the protective effects of lidocaine on inflammatory pain caused by CFA. In conclusion, lidocaine inhibits the inflammatory response and pain through the MAPK/ERK/NF-κB pathway in a rat model of pain induced by CFA.

Natural Products and their (Semi-)Synthetic Forms in the Treatment of Migraine: History and Current Status

BACKGROUND

Migraine may be described as a headache with moderate to extreme pain that is often accompanied by incapacitating neurological symptoms. It is estimated that 12% of the world population suffers from migraine. Although a number of drugs have been used for treatment of migraine, most of these are not effective for every patient and may have undesirable side-effects. Thus, there is an enormous unmet need in current migraine therapy for discovering safer and more effective agents.

METHODS

The information summarized in this review was obtained through extensive literature review and search of relevant books and articles with the use of Web of Knowledge and SciVerse Scopus databases.

RESULTS

Greater understanding of the molecular mechanisms underlying the etiopathogenesis of migraine is helpful in identifying novel targets for antimigraine drugs such as cannabinoid, histamine, and melatonin receptors. In the past, natural product-derived constituents have served as an invaluable source of numerous medicinally useful antimigraine agents and it may be expected that further promising drug candidates from natural products will be discovered for antimigraine pharmacotherapy with better efficacy and fewer adverse-effects.

CONCLUSION

The discovery of novel targets in migraine therapy has opened new horizons for compounds that have not been clinically tested or that previously failed in clinical trials as potential antimigraine drugs. Ginkgolide B, melatonin, histamine, oxytocin, various ribosomal peptide toxins, kavalactones, devil's claw-derived compounds, salvinorin A and petasin are among those agents that show considerable promise as novel drugs in migraine prevention and treatment. It is necessary to conduct more research to better understand their antimigraine action, to confirm their effectiveness and safety, and to introduce them into clinical practice.

Inpatient Management of Migraine

Migraine is a frequently disabling neurologic condition which can be complicated by medication overuse headache and comorbid medical disorders, including obesity, anxiety and depression. Although most migraine management takes place in outpatient clinics, inpatient treatment is indicated for migraine refractory to multiple outpatient treatments, with intractable nausea or vomiting, need for detoxification from medication overuse (such as opioids and barbiturates), and significant medical and psychiatric disease. The goals of inpatient treatment include breaking the current cycle of headache pain, reducing the frequency and/or severity of future attacks, monitored detoxification of overused medications, and reducing disability and improving quality of life.

Lidocaine improves cerebral ischemia-reperfusion injury in rats through cAMP/PKA signaling pathway

Influence of lidocaine on rats with cerebral ischemia-reperfusion injury (CIRI) was studied to explore its mechanism of action. A total of 30 Sprague-Dawley rats were randomly divided into control group and model group, and the rat model of CIRI was prepared by the suture-occluded method in the model group. Then the rats in the model group were randomly assigned into the model group (n=10) and the lidocaine group (n=10). The neurological function score of rats was evaluated, and the levels of serum B-cell lymphoma-2 (Bcl-2) and Bcl-2 associated X protein (Bax) in rats were determined using ELISA. TUNEL assay was performed to detect the neuronal apoptosis in the brain of rats. The messenger ribonucleic acid (mRNA) and protein expression levels of cyclic adenosine monophosphate (cAMP) and protein kinase A (PKA) were measured via RT-PCR and western blotting, respectively. Compared with those in the control group, the rats in the model group had an elevated neurological function score, a raised level of Bcl-2, but a reduced level of Bax in the serum, an obviously increased rate of neuronal apoptosis in the brain and decreased mRNA and protein levels of cAMP and PKA in cerebral tissues. The rats in lidocaine group had a lower neurological function score, a lower level of Bcl-2, but a higher level of Bax in the serum, an evidently lower rate of neuronal apoptosis in the brain and higher mRNA and protein levels of cAMP and PKA in cerebral tissues than those in the model group. Lidocaine can improve the neurological function of rats with CIRI and inhibit neuronal apoptosis in the brain, and its mechanism of action may be related to the activation of the cAMP/PKA signaling pathway.

Comparison of antinociceptive effects of plain lidocaine versus lidocaine complexed with hydroxypropyl-β-cyclodextrin in animal models of acute and persistent orofacial pain

Herein, it was investigated whether a complex of lidocaine with 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) would present a better antinociceptive profile in vivo when compared with plain lidocaine in models of orofacial pain. Plain lidocaine (LDC) and complexed lidocaine (LDC:HP-β-CD) were initially evaluated in vitro to determine the release rate of the two formulations. Subsequently, the effect of both formulations was evaluated in independent groups of rats submitted to the orofacial formalin test, induction of facial heat hyperalgesia by capsaicin and carrageenan, and induction of facial heat and mechanical hyperalgesia by constriction of the infraorbital nerve. LDC:HP-β-CD led to a reduction in the lidocaine release assessed in the in vitro release assay compared to plain LDC. Both formulations presented an antinociceptive effect in all models, but LDC:HP-β-CD showed a better effect in the second phase of the formalin response, in carrageenan-induced heat hyperalgesia, and in the heat hyperalgesia associated to infraorbital nerve constriction. Our results show that complexation improved in vivo antinociceptive effects of LDC, but further studies are necessary to elucidate what properties contribute to the better effect of the complexed formulation on this models and/or what characteristics of the pain model facilitate the action of the complexed formulation.