Propofol does not alter the protein binding and unbound concentration of lidocaine at clinically targeted plasma concentrations in vitro - A short communication.

BACKGROUND: Intravenous lidocaine is increasingly used as an analgesic adjunct during general anaesthesia. Lidocaine is highly protein-bound and changes to binding can alter drug efficacy or toxicity. We aimed to measure the effect of various propofol and lidocaine plasma concentration combinations on the protein binding and concentration of lidocaine in vitro. METHODS: Known targeted concentrations of propofol and lidocaine were added to drug-free human plasma in vitro. Samples were prepared and analysed in various clinically relevant concentration combinations; propofol at 0, 2, 4 and 6 µg/mL, and lidocaine at 1, 3 and 5 µg/mL. The total and unbound concentrations of lidocaine were measured by ultra-high performance liquid chromatography-mass spectrometry and percentage protein binding was determined. Data were presented as mean and standard deviation (SD) and differences between analysed groups. RESULTS: The overall mean protein binding of lidocaine was 68.8% (SD 5.5, range 57.5-80.9%). Beta regression analysis revealed no statistically significant difference in lidocaine percentage binding across a range of propofol and lidocaine concentration combinations. CONCLUSION: Propofol did not alter the unbound and free pharmacologically active proportion of lidocaine at different clinically targeted concentrations of propofol and lidocaine in plasma in vitro. The percentage of plasma protein binding of lidocaine in this study was consistent with previously published results.

Case report: safety and efficacy of lidocaine infusion for the treatment of intractable zoster-associated neuralgia in solid organ transplant recipients.

Introduction: Solid organ transplant recipients are at high risk for developing severe zoster-associated neuralgia, and the pharmaceutic therapies of pain management for these patients with limited organ function are challenging. Intravenous lidocaine infusion showed positive analgesic effects and is used for the management of neuropathic pain. This case series reports the safety and effectiveness of intravenous lidocaine infusion in the treatment of intractable zoster-associated neuralgia in solid organ transplant recipients. Case series presentation: Five solid organ transplant recipients suffering from refractory zoster-associated neuralgia (numeric rating scale 8-10, despite using high doses of antiepileptic drugs or combined with opioids) were enrolled. Intravenous lidocaine (5 mg/kg ideal bodyweight) was administered over 1.5 h with the monitoring of vital signs. Pain intensity, patient satisfaction, adverse events, typical liver, and kidney function were evaluated. All subjects reported high satisfaction with their treatment and effective pain relief at the 6-month follow-up. One patient experienced short and mild numbness in the mouth and dizziness after the therapy, but no major adverse reactions were reported. Conclusion: This case series provides evidence that intravenous lidocaine infusion provided effective pain relief as an analgesic treatment option for transplant patients with intractable zoster-associated neuralgia.

Anesthetic recovery outcomes after 2 methods of nasal mucosal preparation for endoscopic sinus surgery.

PURPOSE: Our institution uses two approaches for nasal mucosal preparation during endoscopic sinus surgery (ESS) to improve surgical field visualization: topical epinephrine (TE) versus topical cocaine with injection of lidocaine containing epinephrine (TCLE). We aimed to compare anesthetic outcomes after ESS using these techniques. METHODS AND MATERIALS: We retrospectively identified adult patients at our institution who underwent ESS from May 2018 through January 2023 under general anesthesia with propofol and remifentanil infusions. Postoperative anesthetic outcomes, including pain and recovery time, were compared between patients who had mucosal preparation with TE versus TCLE using inverse probability of treatment weighting (IPTW) to adjust for potential confounders. RESULTS: Among 1449 patients who underwent ESS, 585 had TE, and 864 had TCLE. Compared with TE, during anesthetic recovery, the TCLE group had fewer episodes of severe pain (numeric pain score ≥ 7) (IPTW-adjusted odds ratio, 0.65; 95 % CI, 0.49-0.85; P = .002), less opioid analgesic administration (IPTW-adjusted odds ratio, 0.55; 95 % CI, 0.44-0.69; P < .001), and shorter recovery room stay (IPTW-adjusted ratio of the geometric mean, 0.90; 95 % CI, 0.85-0.96; P = .002). Postoperative nausea and vomiting and postoperative sedation were similar between groups. CONCLUSIONS: Patients who received preparation of the nasal mucosa with TCLE, compared with TE, were less likely to report severe pain or receive an opioid analgesic in the postanesthesia recovery room and had faster anesthetic recovery. This observation from our large clinical practice indicates that use topical and local anesthetic during endoscopic sinus surgery may have benefit for ambulatory ESS patients.

Immobilisation and Epidural Anaesthesia in a Eurasian Lynx (Lynx lynx) Undergoing Pelvic Limb Orthopaedic Surgery.

Immobilisation and anaesthesia of wild felids may be complex and potentially dangerous events, making it difficult to implement more advanced anaesthetic techniques such as neuraxial anaesthesia. A Eurasian lynx was referred for femur fracture repair after it was seen with lameness of the left pelvic limb sustained in its natural environment. The animal was remotely darted using a combination of ketamine (5 mg/kg) and xylazine (5 mg/kg) intramuscularly. Once immobilised, the lynx was transported to the veterinary hospital in a restraining cage. After induction and endotracheal intubation, pelvic limb radiographs confirmed a closed, comminuted fracture of the left femur that required open reduction and internal stabilisation. A sacrococcygeal epidural was performed before surgery using lidocaine (2 mg/kg) and morphine (0.1 mg/kg) to complement the ketamine-xylazine-isoflurane anaesthesia, which allows a low-end-tidal isoflurane concentration. Clinical signs were continuously monitored and remained stable during the entire procedure, with the exception of a temperature that decreased to 35.8°C. No intraoperative analgesic rescues were necessary. Recovery was smooth and uneventful. The lynx showed no signs of motor weakness after surgery or other side effects related to the anaesthetic procedure. The successful management of this surgical case suggests that the described anaesthetic protocol could be recommended in orthopaedic procedures of the pelvic limbs in wild Felidae.

Effect of Lidocaine-prilocaine Cream on Using CPAP Mask Amongst Patients Undergone PAPtitration Study for Obstructive Sleep Apnea: A Randomized Controlled Trial Study.

Background/objective: Despite the high efficacy of using Continuous positive airway pressure (CPAP) in reversing upper airway obstruction in obstructive sleep apnea (OSA), the efficiency of this treatment is limited due to the low adherence. Mask pressure is suggested to play a significant role in adherence. In this study, we intend to investigate the effect of Lidocaine-prilocaine cream CPAP mask on pressure sensation. Methods: In this study, 75 patients referred to CPAP titration were divided into three groups. In groups one and two, Lidocaine-prilocaine cream and Petroleum jelly were used respectively. The third group had no intervention. Results: VAS discomfort immediately (VAS0), after 15 min (VAS15), and the next day (VAS all) in three groups were compared. VAS0, VAS15, and VAS all were not significantly different among the three groups (P > 0.05). Among participants with VAS0 above 5, VAS15 was significantly lower in intervention groups than the control group (P < 0.05). Conclusion: This study shows that both Petroleum jelly and Lidocaine-prilocaine cream can be used for decreasing pressure sensation during CPAP titration among patients who suffer excessive facial discomfort immediately after putting on a CPAP mask.

Dexmedetomidine mitigates lidocaine-induced spinal cord injury by repressing ferritinophagy-mediated ferroptosis by increasing CISD2 expression in rat models.

Dexmedetomidine (DEX) has been confirmed to exert neuroprotective effects in various nerve injury models by regulating ferroptosis, including spinal cord injury (SCI). Although it has been established that CDGSH iron sulfur domain 2 (CISD2) can regulate ferroptosis, whether DEX can regulate ferroptosis by CISD2 in SCI remains unclear. Lidocaine was used to induce PC12 cells and stimulate rats to establish SCI models in vitro and in vivo. MTT assays were performed to analyze cell viability. Ferroptosis was assessed by determining the levels of cellular reactive axygen species (ROS), malondialdehyde (MDA), glutathione (GSH), and Fe2+. Ferritinophagy was analyzed by LysoTracker staining, FerroOrange staining, and immunofluorescence. Western blotting was carried out to quantify the levels of several proteins. Fluorescence microscopy was also used to observe cell autophagy. The morphology of mitochondria within the tissue was observed under transmission electron microscopy (TEM). DEX treatment weakened lidocaine-induced elevation of ROS, Fe2+, and MDA and reduced GSH in PC12 cells, indicating that DEX treatment weakened lidocaine-induced ferroptosis in PC12 cells. Similarly, lidocaine promoted autophagy, Fe2+, and microtubule-associated protein 1 light chain 3 (LC3) in PC12 cells and suppressed ferritin and p62 protein levels, indicating that DEX could weaken lidocaine-induced ferritinophagy in PC12 cells. DEX treatment improved the BBB score, reduced tissue damage, increased the number of neurons, and alleviated mitochondrial damage by inhibiting ferroptosis and ferritinophagy in lidocaine-induced SCI rat models. The decreased CISD2, ferritin heavy chain 1 (FTH1), solute carrier family 7-member 11-glutathione (SLC7A11), and glutathione peroxidase 4 (GPX4) protein levels and the elevated nuclear receptor coactivator 4 (NCOA4) protein levels in rat models in the lidocaine group were weakened by DEX treatment. Moreover, CISD2 inhibition reversed the inhibitory effects of DEX treatment on lidocaine-induced ferroptosis and ferritinophagy in PC12 cells significantly. Taken together, DEX treatment could impair lidocaine-induced SCI by inhibiting ferroptosis and ferritinophagy by upregulating CISD2 in rat models.

Epidural block with lidocaine ameliorates kidney function deterioration and fibrosis of CKD in rats.

BACKGROUND: According to evidences from clinical practices and experiments, renal denervation achieved by removing both the afferent and sympathetic nerves has therapeutic impacts on poor renal function and hypertension in chronic kidney disease (CKD). Epidural anesthesia is presumed to function on the target spine segments with a complete sympathetic block. Based on this perspective, we hypothesized that epidural block with lidocaine could ameliorate renal injury in CKD rats. METHOD AND RESULTS: Male Sprague-Dawley rats weighing 250-300g were randomized into four groups: control, CKD, CKD + sham, and CKD + epidural block with lidocaine groups. CKD was induced by resection of the lower and upper thirds of the left kidney followed by right nephrectomy one week later. Significant differences in renal function, sympathetic activation as well as renal fibrosis parameters were observed between CKD and control rats. These parameters corresponded with typical phenotypes of CKD rats. Epidural block with lidocaine improved renal function as well as renal fibrosis, and reversed the abnormalities of the renal function and cardiovascular parameters either fully or partially. CONCLUSION: Epidural block with lidocaine confers renal protection, which is presumably mediated by decreasing sympathetic nerve activities in the renal region and other target organs in CKD.

Application of articaine in endoscopic endonasal dacryocystorhinostomy: a retrospective study.

Background: To investigate the comparative effects of local anesthesia using lidocaine with adrenaline vs. articaine with adrenaline in endoscopic endonasal dacryocystorhinostomy (EN-DCR). Methods: This retrospective study included a total of 180 patients. These patients were categorized into two groups: the lidocaine group, which received 2% lidocaine (1:100,000 adrenaline), and the articaine group, which received 4% articaine (1:100,000 adrenaline) for local anesthesia. The study compared anesthesia efficacy, intraoperative pain levels, intraoperative bleeding, as well as differences in heart rate and blood pressure between the two groups. Results: The articaine group demonstrated a significantly lower visual analog scale (VAS) pain score when compared to the lidocaine group, measuring at 4.4 ± 0.6 cm vs. 5.0 ± 1.0 cm, respectively (P < 0.0001). Additionally, the articaine group exhibited a higher anesthesia efficacy compared to the lidocaine group (89.0% vs. 76.6%, p = 0.0487). Notably, the articaine group experienced less nasal mucosal bleeding during the surgery in contrast to the lidocaine group (p = 0.004). However, there were no statistically significant differences in changes in blood pressure and heart rate between the two groups (p > 0.05). Conclusion: This study demonstrated that 4% articaine (1:100,000 adrenaline) has superior clinical effectiveness in comparison to 2% lidocaine (1:100,000 adrenaline) in EN-DCR.

The Effect of Lidocaine-Prilocaine Cream Combined with or Without Remimazolam on VAS and APAIS Anxiety Score in Patient Undergoing Spinal Anesthesia.

Purpose: This study aimed to investigate patients' expectative pain of spinal anesthesia puncture and anxiety pre-anesthesia, and to examine the effect of lidocaine-prilocaine cream and remimazolam prior to spinal anesthesia puncture on pain relief and anxiety release. Methods: Patients undergoing spinal anesthesia were divided into control, lidocaine-prilocaine cream, and lidocaine-prilocaine cream with remimazolam groups. A questionnaire consisting of The Amsterdam Preoperative Anxiety and Information Scale (APAIS) and patient's concerns and Visual Analog Scale (VAS) was used to evaluate patient's anxiety and pain. The primary outcomes were differences in VAS and anxiety scores. Patient's spinal anesthesia-related concerns, advent events and hemodynamic index were also recorded. Results: The expected spinal anesthesia puncture pain was 5.34±0.27 and anxiety scores before spinal anesthesia was 10.88 ± 0.64. A statistically significant positive correlation of 31.3% was detected between VAS and APAIS scores (r = 0.313; P=0.003). The VAS score at the time of puncture decreased by 29.7% (3.78±0.40, P=0.001) in lidocaine-prilocaine cream group and 29.2% (3.75±0.39, P=0.001) in lidocaine-prilocaine cream with remimazolam group compared with the expected VAS score. Lidocaine-prilocaine cream combined with or without remimazolam reduced the percentage of moderate pain (21.4% and 31.3% vs 50.0%, P=0.0001) and increased mild pain (60.7% vs 59.4% vs 22.7%, P=0.03). Anxiety score in lidocaine-prilocaine cream group was reduced by 2.84 (8.04±0.76 vs 10.88 ± 0.46, P=0.05) when compared with pre-anesthesia. Concerns about postoperative pain (P=0.03) and fear of the needle or intervention (P=0.000) both decreased post-anesthesia among groups. Conclusion: Approximately half of the patients scheduled for spinal anesthesia experienced a moderate level of preoperative anxiety. The patient's pain expectation from the spinal anesthesia puncture was moderate, which was higher than the actual pain. Lidocaine-prilocaine cream with or without remimazolam sedative before spinal anesthesia puncture reduced the patient's pain and anxiety scores after surgery.

Centripetal endoscopic sinus surgery in rhinogenic headache.

OBJECTIVES: The aim of this manuscript is to analyse a diagnostic protocol to select correctly patients with Rhinogenic Headache Contact Point (RH) and to investigate the effect of surgical treatment and medical therapy in pain relief. METHODS: A prospective no-randomized study selected adult patients with headache and nasal alteration at CT exam or endoscopic vision with positive response to test with nasal spray with corticosteroids and antihistamine or/and local anesthesia test to the contact points. MIDAS score, intensity score, daily duration of symptoms, frequency of headache in the last month were collected in patients who performed surgery and in patients who performed medical therapy. RESULTS: Following the inclusion, 415 patients were selected for this study. 302 patients performed nasal surgery (septoplasty, turbinoplasty and/or endoscopic surgery with centripetal technique), 113 performed medical therapy. There was a statistically significant improvement in MIDAS score, intensity score, daily duration of symptoms, frequency of headache in the last month in patients who performed surgery and in patients who performed medical therapy. Regarding the comparison between patients who performed surgery (Group A) and patients who performed only medical therapy for RH (Group B), better outcomes were obtained by Group A. Considering the daily life handicap index, the lowest handicap was obtained in Group A. CONCLUSION: This study demonstrates that surgery, using in some cases centripetal technique, gives an improvement statistically significant than medical therapy in RH. The use of nasal spray with corticosteroids and with anti-histamine is a good method in the diagnosis of RH, especially in patients with anatomical variants such as concha bullosa, agger nasi cells and Haller cells.

Lidocaine HCl-Loaded Polyelectrolyte Complex -Poloxamer Thermoresponsive Hydrogel: In Vitro- In Vivo Anesthetic Evaluations for Tooth Socket Wound Delivery.

Local anesthesia is essential in dental practices, particularly for managing pain in tooth socket wounds, yet improving drug delivery systems remains a significant challenge. This study explored the physicochemical characteristics of lidocaine hydrochloride (LH) incorporated into a polyelectrolyte complex and poloxamer thermosensitivity hydrogel, assessing its local anesthetic efficacy in mouse models and its onset and duration of action as topical anesthetics in clinical trials. The thermoresponsive hydrogel exhibited a rapid phase transition within 1-3 minutes and demonstrated pseudo-plastic flow behavior. Its release kinetics followed Korsmeyer-Peppas, with 50% of biodegradation occurring over 48 h. In mouse models, certain thermogels showed superior anesthetic effects, with rapid onset and prolonged action, as evidenced by heat tolerance in tail-flick and hot plate models. In clinical trials, the LH-loaded thermoresponsive hydrogel provided rapid numbness onset, with anesthesia (Ton) beginning at an average of 46.5 ± 22.5 seconds and lasting effectively (Teff) for 202.5 ± 41.0 seconds, ranging from 120 to 240 seconds, indicating sustained release. These results highlight the promising properties of these formulations: rapid onset, prolonged duration, mucoadhesion, biodegradability, and high anesthesia effectiveness. This study demonstrates the potential for advancing local anesthesia across various medical fields, emphasizing the synergy between material science and clinical applications to improve patient care and safety.

Dermatoscope for the diagnosis of erythema with purpura induced by lidocaine/prilocaine cream: A case report.

BACKGROUND: Lidocaine/prilocaine (EMLA) cream is a local anesthetic that is applied to the skin or mucosa during painful therapeutic procedures with few reported side effects. CASE SUMMARY: Here, we report the use of dermatoscopy to identify a case of erythema with purpura, a rare side effect, after the application of 5% EMLA cream. CONCLUSION: We conclude that erythema with purpura is caused by irritation and toxicity associated with EMLA, but the specific mechanism by which the toxic substance affects skin blood vessels is unclear. In response to this situation and for cosmetic needs, we recommend tranexamic acid, in addition to routine therapy, to prevent changes in pigmentation in patients with dermatitis.

Effect of lidocaine pumped through hepatic artery to relieve pain of hepatic artery infusion chemotherapy.

Background: This study aims to explore the analgesic effect of lidocaine administered through the hepatic artery during hepatic artery infusion chemotherapy (HAIC) for hepatocellular carcinoma (HCC). Methods: A total of 45 HCC patients were randomly divided into a study group and a control group. Both groups received oxaliplatin (OXA) based FOLFOX protocol via electronic infusion pump. The study group was continuously infused with 100 mg of lidocaine during HAIC, while 5% glucose solution was infused in the same way as described above. Changes in vital signs, visual analogue score (VAS) and general comfort score (GCQ scale) were recorded before surgery (Time point 0), at the end of infusion (Time point 01), 1 h after HAIC (Time point 02), 3 h after HAIC (Time point 03) and 6 h after HAIC (Time point 04). Results: At each point of time from Time point 0 through Time point 04, the differences in MAP, RR and SPO2 between the two groups were not statistically significant (P > 0.05). At each point of time from Time point 01 through Time point 04, the mean VAS scores in the study group were smaller and GCQ scores were higher than those in the control group, and the differences were both statistically significant (P < 0.05). Conclusions: Lidocaine infusion through the hepatic artery during HAIC effectively reduces intraoperative and postoperative pain and improves patient satisfaction with pain management, making it a valuable technique for clinical practice.

Effectiveness of intracuff alkalinized lidocaine associated with intravenous dexamethasone in reducing laryngotracheal morbidity in children undergoing general anesthesia for tonsillectomy: a randomized controlled trial.

BACKGROUND: Postoperative sore throat is one of the main postoperative complaints in patients undergoing tonsillectomy. As the primary outcome, we aimed to determine whether endotracheal tube cuffs filled with alkalinized lidocaine are associated with a lower incidence of postoperative sore throat and anesthesia emergence phenomena in children undergoing tonsillectomy or adenotonsillectomy. We also assessed the potential additional benefits of IV dexamethasone in reducing postoperative laryngotracheal morbidity. METHODS: This is a clinical prospective, randomized, controlled trial. Patients were randomly allocated to one of four groups, as follows: air - endotracheal tube cuff filled with air; air/dex - endotracheal tube cuff filled with air and intravenous dexamethasone; lido - endotracheal tube cuff filled with alkalinized lidocaine; and lido/dex - endotracheal tube cuff filled with alkalinized lidocaine and intravenous dexamethasone. Perioperative hemodynamic parameters and the incidence of postoperative nausea and vomiting, coughing and hoarseness were recorded. Postoperative sore throat was assessed in the postanesthetic care unit and 24 hours post tracheal extubation. RESULTS: In total, 154 children aged 4-12 years, ASA physical status I or II, undergoing general anesthesia for elective tonsillectomy and adenotonsillectomy, were assessed for postoperative sore throat in this study. The incidence of postoperative sore throat 24 hours after tracheal extubation was significantly lower in the lido/dex group compared to groups air and air/dex (p = 0.01). However, no additional reduction in these symptoms was observed from the intravenous administration of dexamethasone when comparing the lido and lido/dex groups. Similarly, there were no differences among groups regarding perioperative hemodynamic variables or postoperative nausea and vomiting, coughing, and hoarseness during the study period. CONCLUSION: Intracuff alkalinized lidocaine, associated with intravenous dexamethasone, might be effective in reducing sore throat 24 hours post-tonsillectomy or adenotonsillectomy in children when compared to the use of air as the cuff insufflation media.

Toxic and signaling effects of the anaesthetic lidocaine on rice cultured cells.

Most studies on anesthesia focus on the nervous system of mammals due to their interest in medicine. The fact that any life form can be anaesthetised is often overlooked although anesthesia targets ion channel activities that exist in all living beings. This study examines the impact of lidocaine on rice (Oryza sativa). It reveals that the cellular responses observed in rice are analogous to those documented in animals, encompassing direct effects, the inhibition of cellular responses, and the long-distance transmission of electrical signals. We show that in rice cells, lidocaine has a cytotoxic effect at a concentration of 1%, since it induces programmed reactive oxygen species (ROS) and caspase-like-dependent cell death, as already demonstrated in animal cells. Additionally, lidocaine causes changes in membrane ion conductance and induces a sharp reduction in electrical long-distance signaling following seedlings leaves burning. Finally, lidocaine was shown to inhibit osmotic stress-induced cell death and the regulation of Ca2+ homeostasis. Thus, lidocaine treatment in rice and tobacco (Nicotiana benthamiana) seedlings induces not only cellular but also systemic effects similar to those induced in mammals.

The TWIK-related acid sensitive potassium 3 (TASK-3) channel contributes to the different effects of anesthetics on the growth and metastasis of ovarian cancer cells.

Different anesthetics exert different effects on the long-term outcomes of various cancers. The TWIK-related acid sensitive potassium 3 (TASK-3) channel is an important target of anesthetics and is upregulated in various cancers. However, the role and underlying mechanism of TASK-3 channel in the effects of anesthetics on ovarian cancer remain unknown. Here, we tested whether the TASK-3 channel contributes to the effects of anesthetics on ovarian cancers. We found that the TASK-3 channel was overexpressed in human ovarian cancer and ovarian cancer cell lines. Clinically relevant concentrations of lidocaine, as a TASK-3 channel inhibitor, exert inhibitory effects on tumor growth and metastasis of ovarian cancer cells in vitro and in vivo, whereas the TASK-3 channel potent activator sevoflurane had protumor effects and propofol had no significant effects on tumor growth and metastasis of ovarian cancer. Knockdown of the TASK-3 channel by TASK-3 shRNA attenuated the effects of lidocaine and sevoflurane. Moreover, mitochondrial TASK-3 channel contributes to the effects of lidocaine and sevoflurane on the mitochondrial functions of ovarian cancer. Taken together, the TASK-3 channel, especially the mitochondrial TASK-3 (MitoTASK-3) channel, is a molecular substrate for the effects of lidocaine and sevoflurane on the tumor growth and metastasis of ovarian cancer.

Buccal lidocaine mucoadhesive patches for pediatrics' teething pain: Overcoming possible hazards of oral gels.

OBJECTIVES: The utilization of pharmaceutical products in pediatric medicine, while established for use in adults, often presents uncertainties due to differences in application for children. The FDA discourages the use of local anesthetic gels, notably lidocaine, for teething pain in pediatrics due to concerns regarding potential adverse effects if inadvertently swallowed excessively. Therefore, significant attention is being directed towards modifying available marketed products to make them suitable for pediatric use. Here, we introduce mucoadhesive patches that not only have an adjusted dose of lidocaine but also feature a controlled release profile to manage teething pain with prolonged effect. This design helps to prevent issues related to gel liquefaction and swallowing, thereby reducing the potential hazardous side effects of lidocaine in the pediatric population. METHODS: The study involved the development of controlled-release lidocaine HCl-loaded pellets forming a matrix for inclusion in mucoadhesive patches. Characterization was performed to ensure prolonged drug release, particularly during overnight use, aiming to improve pediatric patient compliance and enable precise dosing. KEY FINDINGS: The mucoadhesive patches exhibited sustained lidocaine release lasting 24 hours, potentially offering overnight relief suitable for pediatric application. The analysis of lidocaine content revealed that the developed patches maintained stable levels compared to doses obtained from commercially available oral gels. This finding implies effective pain control without the need for frequent reapplications, alongside controlled doses that decrease the likelihood of side effects. CONCLUSION: The formulated medicated patches demonstrated consistent lidocaine content, effectively controlled drug release, and consequently, reduced the likelihood of undesired side effects when compared to oral gel administration.

Effect of Dental Local Anesthetics on Reactive Oxygen Species: An In Vitro Study.

Introduction Oxidative stress, an imbalance between reactive oxygen species (ROS) production and antioxidant defenses, plays an important role in various dental diseases. Local anesthetics are frequently used in dentistry. The potential antioxidant activity of dental local anesthetics can contribute to dental practice. Therefore, this study aimed to investigate the ROS-scavenging activities of three commonly used dental local anesthetics, lidocaine, prilocaine, and articaine, focusing on their effects on hydroxyl radicals (HO•) and superoxide anions (O2 •-). Materials and methods The electron spin resonance (ESR) spin-trapping technique was employed to specifically measure the ROS-scavenging activities of these local anesthetics at varying concentrations. Results Lidocaine, prilocaine, and articaine exhibited concentration-dependent HO•-scavenging activities, with IC50 values of 0.029%, 0.019%, and 0.014%, respectively. Lidocaine and prilocaine showed concentration-dependent O2 •--scavenging activity, with IC50 values of 0.033% and 0.057%, respectively. However, articaine did not scavenge O2 •-. Conclusions The proactive use of dental local anesthetics may mitigate oxidative injury and inflammatory damage through direct ROS scavenging. However, further research is needed to elucidate the specific mechanisms underlying the antioxidant effects of these dental local anesthetics and their potential impact on the dental diseases associated with oxidative stress.

Ultrasound-guided quadratus lumborum block in sheep: A cadaveric study.

This prospective anatomical study aimed to establish an ultrasound-guided technique to the quadratus lumborum (QL) plane in sheep cadavers. Thirteen cadavers, weighing less than 117 kg, were included. In phase 1, one cadaver underwent dissection and two cadavers underwent 3D computed tomographic reconstruction for anatomical evaluation of the thoracolumbar region. In phase 2, two cadavers were used to compare two ultrasound techniques to the QL plane: lateral to the QL muscle with a transversal approach (LQL) and transmuscular between QL and psoas muscles with a longitudinal approach (TQL). For LQL, the reference was the first lumbar transverse process, whereas for TQL, it was the intertransverse region between the first and second lumbar vertebrae. The needle was advanced in-plane towards the specific target for each technique and a total of four injections were performed using 0.4 ml kg-1 of a dye-lidocaine solution. In phase 3, 10 cadavers received bilateral LQL injections (n = 20). All cadavers were then dissected to evaluate spread of dye. In phase 2, following LQL injections, no dye was observed in undesired locations; however, the dye was noted in the retroperitoneal space (1/2) after TQL injections. In phase 3, the 13th thoracic, first, second, third lumbar nerves, and sympathetic trunk segments were stained in 80%, 95%, 100%, 45% and 35% of the injections, respectively. In conclusion, the LQL technique was feasible, allowing staining of the spinal nerves innervating the cranial abdomen in sheep cadavers. Further studies in live animals are warranted.

Eugenol and lidocaine inhibit voltage-gated Na+ channels from dorsal root ganglion neurons with different mechanisms.

Eugenol (EUG) is a bioactive monoterpenoid used as an analgesic, preservative, and flavoring agent. Our new data show EUG as a voltage-gated Na+ channel (VGSC) inhibitor, comparable but not identical to lidocaine (LID). EUG inhibits both total and only TTX-R voltage-activated Na+ currents (INa) recorded from VGSCs naturally expressed on dorsal root ganglion sensory neurons in rats. Inhibition is quick, fully reversible, and dose-dependent. Our biophysical and pharmacological analyses showed that EUG and LID inhibit VGSCs with different mechanisms. EUG inhibits VGSCs with a dose-response relationship characterized by a Hill coefficient of 2, while this parameter for the inhibition by LID is 1. Furthermore, in a different way from LID, EUG modified the voltage dependence of both the VGSC activation and inactivation processes and the recovery from fast inactivated states and the entry to slow inactivated states. In addition, we suggest that EUG, but not LID, interacts with VGSC pre-open-closed states, according to our data.