Pharmacokinetics and pharmacodynamics of lignocaine: A review

Intravenous Lidocaine for Gut Function Recovery in Colonic Surgery: A Randomized Clinical Trial

Importance

Despite the recovery advantages of minimally invasive surgical techniques, delayed return of gut function after colectomy is a common barrier to timely discharge from hospital.

Objective

To evaluate the effect of 2% perioperative intravenous lidocaine infusion on return of gut function after elective minimally invasive colon resection.

Design, Setting, and Participants

The ALLEGRO trial was a randomized, placebo-controlled, double-blind trial conducted in 27 UK hospitals. A total of 590 adults scheduled for elective minimally invasive colon resection for benign or malignant disease were randomized 1:1 to 2% intravenous lidocaine or saline placebo. Enrollment occurred from August 13, 2018, to April 11, 2023, with a pause in recruitment from March 20, 2020, through July 6, 2020; final follow-up was on August 10, 2023.

Interventions

The intervention patients received 2% intravenous lidocaine administered as 1.5-mg/kg bolus at induction of anesthesia followed by 1.5 mg/kg/h for 6 or 12 hours. Control patients received 0.9% saline placebo for 6 or 12 hours.

Main Outcomes and Measures

The primary outcome was the proportion of patients with return of gut function at 72 hours after surgery, defined by the GI-3 composite end point of tolerating diet (ingestion of food and drink without significant nausea or vomiting for 3 consecutive meals) and passage of flatus or stool. There were 11 secondary outcomes, including time to GI-3 recovery, time to GI-2 recovery (tolerance of oral diet and passage of stool), prolonged postoperative ileus, postoperative nausea and vomiting score, Overall Benefit of Analgesia Score, postoperative opioid consumption, Quality of Recovery-15, quality of life (EuroQol 5-Dimension 5-Level), enhanced recovery protocol adherence, time to meeting medically defined criteria for discharge, and time to patient self-assessed readiness for discharge.

Results

The trial enrolled 590 patients (295 intervention, 295 control); after 33 postrandomization exclusions, 557 patients were included (279 intervention, 278 control; 249 female patients [44.7%]; mean [SD] age, 66 [10.9] years); 532 (96%) received the randomized treatment. Return of gut function as defined by the GI-3 composite outcome was achieved at 72 hours by 160 patients (57.3%) in the intravenous lidocaine group vs 164 patients (59.0%) in the placebo group (adjusted absolute difference, -1.9% [95% CI, -8.0% to 4.2%]; relative risk, 0.97 [95% CI, 0.88 to 1.07]). There was no significant difference between the intervention and control groups in any of the 11 secondary end points.

Conclusions and Relevance

Among patients undergoing elective minimally invasive colon resection, perioperative administration of 2% intravenous lidocaine did not improve return of gut function at 72 hours.

Trial Registration

isrctn.org Identifier: ISRCTN52352431.

Making Sense of Topical Pain Relief Options: Comparing Topical Analgesics in Efficacy and Safety

CONTEXT

In patients with musculoskeletal (MSK) conditions, pain is the leading contributor to disability and significantly limits mobility and dexterity. This narrative review describes the efficacy and safety of topical analgesics in common use today.

EVIDENCE ACQUISITION

Secondary literature gained via a literature search using PubMed.gov and the Cochrane library were used.

STUDY DESIGN

Recent literature (2000-2023) on several major classes of topical analgesics and topical delivery systems were reviewed to provide strength of recommendation taxonomy (SORT) levels. A total of 86 articles were reviewed.

LEVEL OF EVIDENCE

Level 2.

RESULTS

Topical nonsteroidal anti-inflammatory drugs (NSAIDs) and cabbage leaf wraps (CLW) appear to be best suited for multiple types of acute MSK pain, and topical nitroglycerin is helpful when used specifically for rotator cuff pain in patients seeking relief while performing activities of daily living and willing to treat for long periods of time. For compounded topical formulations, it may be better to offer single agent creams based on patient preferences. Little data support the use of cryotherapy. Traumeel could be a promising natural analgesic that compares with diclofenac. Topical lidocaine appears best suited for postherpetic neuropathic pain. O24 is a reasonable alternative with a low risk profile to treat pain in patients with fibromyalgia syndrome.

CONCLUSION

Choice of topical agents should be guided by current evidence accounting for type of pain, medication side effects, patient comorbidities, as well as patient preference, convenience, and cost.

STRENGTH-OF-RECOMMENDATION TAXONOMY (SORT)

Of the topical analgesics and modalities reviewed, SORT level A evidence was found for topical NSAID use in decreasing MSK pain, topical lidocaine for postherpetic neuralgia, and nitroglycerin patches for treating rotator cuff pain if used for prolonged periods of time. Alternative treatments such as CLW and Traumeel show promising results (SORT level B).

Comparison of hemodynamic responses to nasal intubation in cancer patients receiving opioid-free general anesthesia versus standard regimen

Background and Aims

Nasotracheal intubation evokes greater hemodynamic responses than oral intubation. We compared the heart rate (HR) and mean arterial pressure (MAP) responses following nasal intubation during opioid-free anesthesia (OFA) using intravenous lignocaine versus standard regimen using morphine in cancer patients undergoing tumor resection.

Material and Methods

This randomized, double-blinded study was conducted in 84 adults. Group A received lidocaine bolus 1.5 mg/kg over 10 min followed by infusion of 1 mg/kg/h. Group B received morphine 0.2mg/kg bolus over 10 min followed by infusion of 2mg/h. Protocols for induction and intubation were similar.

Results

Mean HR and MAP at preinduction, immediately after induction, and at 1, 3, and 5 min after intubation were comparable in groups A and B. Intragroup comparison of preinduction HR with subsequent values in group A showed that the HR values at 1,3, and 5 min after intubation were significantly higher than the preinduction value. HR after induction was comparable. Intragroup analysis in group B showed that preinduction HR was comparable with HR after induction and at 3 and 5 min after intubation. HR at 1 min was significantly higher. Intragroup analysis in group A showed that the MAP values were significantly lower than the preinduction value after induction and at 1,3, and 5 min after intubation. In group B, MAP was significantly lower than the preinduction value after induction and at 3 and 5 min after intubation, with the value being comparable at 1 min.

Conclusion

OFA with lignocaine bolus followed by infusion, as well as morphine did not attenuate the HR responses to nasal intubation in cancer patients. However, both techniques effectively blunted the MAP response.

Description and management of patients with anal fissure: insights on Italian primary care setting coming from real-world data

To describe patients with anal fissure (AF) and their management in primary care. Retrospective study using the Italian Longitudinal Patient Database on 18 + years old subjects with AF records during 'July 2016-June 2021' (selection period). Index Date (ID) was the first AF record during selection period. Sub-cohorts were defined by presence/absence of prescriptions on ID of the combination of topical nifedipine 0.3% and lidocaine 1.5% (NIF/LID). Patients' information on the 12-month period before (baseline) and after (follow-up) ID was analyzed. Subjects with AF were 8632: 14.0% had NIF/LID on ID. Mean age was 52 (± 17.2) years, there were more women in ' < 50 years' group, and more men in '50-70' one. Prevalences of pregnancy and immunodepression were around 5%; most common comorbidities were hypertension (29.6%) and heart disease (13.1%), while constipation and diarrhea were < 5%. Healthcare resources utilization (HRUs) increased during follow-up, but still few patients were prescribed NIF/LID (2.8%), other treatments for AF (10.3%), or proctological visits (7.7%). NIF/LID patients were younger (< 40 years people: 30.7% versus 23.9%; p value < 0.0001), and more likely to have constipation (4.3% versus 2.5%; p value < 0.001); patients without NIF/LID showed slightly higher prevalences of hypertension (30.0% versus 27.1%; p value: 0.039) and depression (4.0% versus**2.5%; p value: 0.009), and a little higher overall HRUs. Results show that general practitioners are used to manage AF. However, there is still a gap between guidelines' recommendations and actual management. Educational campaigns on common anal problems in primary care might help further improving AF management and optimizing HRUs.

The role of intravenous lidocaine infusion in enhanced recovery after laparoscopic renal surgeries: A randomized control trial

Background and Aims

Enhanced recovery after surgery (ERAS) has been applied in various laparoscopic procedures. Intravenous lidocaine (IVL) infusion is used for laparoscopic procedures as a part of ERAS protocols. The study aimed to evaluate the role of IVL infusion in enhanced bowel recovery after laparoscopic renal surgeries.

Material and Methods

A randomized, double-blind, placebo-control trial was conducted on 80 patients (with American Society of Anesthesiologists physical status I-II) who presented for laparoscopic renal surgeries under general anesthesia. The study period was from Oct 2018 to Sept 2019. By computer-generated codes, patients were randomly divided into two groups: L (lidocaine) and C (control). Group L received an intravenous (IV) bolus (1.5 mg/kg) of 2% lidocaine over 2 min, followed by an IV lidocaine infusion at the rate of 1.5 mg/kg/h until skin closure. Group C received the same volume of bolus followed by normal saline infusion. Patients were monitored for bowel functions, total hospital stay, and total analgesic consumption. Student's t-test and Chi-square test were used for quantitative data and occurrence of events, respectively. P <0.05 was considered to be statistically significant.

Results

First bowel sound, flatus, and defecation occurred in 16.4 ± 2.50, 26.7 ± 9.02, and 39.1 ± 6.31 h, respectively, in group L and 18.2 ± 2.90, 32.3 ± 3.11, and 43.3 ± 4.22 h, respectively, in group C (P = 0.006, 0.001, and 0.01, respectively). Total hospital stay was 4.0 ± 0.74 and 5.3±0.0.91 days in groups L and C, respectively (P < 0.001).

Conclusion

The present study concluded that IVL could enhance the bowel recovery and reduce total hospital stay after laparoscopic renal surgeries.

Evaluation of effects of intravenous infusion of dexmedetomidine or lignocaine on stress response and postoperative pain in patients undergoing craniotomy for intracranial tumors: A randomized controlled exploratory study

Background

Goals of anesthesia in neurosurgery include stable cerebral hemodynamics and provide relaxed brain to surgeon. Dexmedetomidine and lignocaine as an adjuvant can fulfill these criteria but literature comparing the two are sparse. We compared the effects of intravenous infusion of dexmedetomidine or lignocaine on stress response, postoperative pain, and recovery in patients undergoing craniotomy for intracranial tumors.

Methods

Approval was obtained from IEC, and the study was prospectively registered (CTRI/2022/11/047434). Written and informed consent was obtained from 105 patients fulfilling inclusion criteria, and they were divided into three groups. Group D received intravenous infusion of dexmedetomidine 1 mcg/kg over 15 minutes followed by infusion at rate of 0.5 mcg/kg/h, Group L received intravenous infusion of lignocaine 2 mg/kg over 15 minutes followed by infusion at rate of 1.5 mg/kg/h, and Group N received intravenous infusion of normal saline at the rate of 4-8 ml/h till skin suturing. SPSS v23 (IBM Corp.) was used for data analysis.

Results

There was a significant difference between groups in terms of intraoperative hemodynamic variations, brain relaxation score, extubation criteria, postoperative pain, stress indicator response, and quality of recovery.

Conclusions

Dexmedetomidine as an adjuvant to anesthetic drugs has a better profile than lignocaine in suppressing stress response and preventing hemodynamic variations at intubation, skull pin application, and surgical incision. Dexmedetomidine increases the duration of effective analgesia more than lignocaine, in postoperative period in patients undergoing craniotomy.

Massive lignocaine overdose while on veno-arterial extracorporeal membrane oxygenation (VA ECMO)

We present the extraordinary circumstance of a female patient in her sixties who suffered a massive lignocaine overdose while undergoing treatment with Veno-Arterial Extracorporeal Membrane Oxygenation (VA ECMO) following an emergency coronary artery bypass graft (CABG). The patient was initially admitted to the Intensive Care Unit (ICU) due to unstable angina and a history of insulin-dependent type two diabetes mellitus, hypertension, hypercholesterolemia, carotid artery stenosis, and an extensive smoking history. Despite initial improvements following surgery, she experienced repeated episodes of nonsustained polymorphic ventricular tachycardia (VT) that were refractory to conventional antiarrhythmic medications. The overdose occurred due to a medication administration error, leading to the infusion of lignocaine at a rate eight times higher than intended, over the course of 36 h (total dose of 9964 mg, or 153 mg/kg). Remarkably, the patient remained haemodynamically stable throughout the overdose period, with normal sinus rhythm, requiring minimal ECMO support and no vasoactive agents. Further investigation into the pharmacokinetics of lignocaine during VA ECMO treatment suggested that the patient's unexpected stability and survival could be attributed to the adsorption of lignocaine onto the components of the ECMO circuit. This phenomenon potentially mitigated the cardiotoxic effects typically associated with such high doses of lignocaine, thus presenting an unusual but critical aspect of pharmacokinetics in the context of ECMO support. This case underscores the importance of investigating the complex interactions between medications and extracorporeal circuits, which can significantly alter drug pharmacokinetics and toxicity profiles.

Beyond Traditional Pain Relief: A Review of Alternative Analgesics in Myocardial Infarction Patient Management

While morphine is the recommended first-line treatment for pain management in patients with acute coronary syndrome, recent studies have raised concerns about its association with adverse outcomes. Morphine has been found to cause delayed antiplatelet effects, decreased ticagrelor absorption, increased platelet reactivity, and compromised efficacy of dual antiplatelet therapy (DAPT). Alternative analgesics, such as lidocaine, fentanyl, and acetaminophen, have begun to emerge as viable alternatives, each with unique mechanisms and potential benefits. Lidocaine is demonstrated to have superior effects in reducing microvascular obstruction and fewer adverse events compared to fentanyl, despite being less effective in pain reduction. Fentanyl, which shows rapid onset and powerful analgesic properties, may interfere with ticagrelor absorption, potentially affecting platelet inhibition. Acetaminophen, a centrally acting analgesic, emerges as a safer alternative with comparable pain relief efficacy and minimal side effects. The results of multiple clinical trials emphasize the significance of customizing pain management approaches to match individual patient profiles and achieving the optimal balance between pain relief and potential adverse outcomes.

Pediatric antiarrhythmics and toxicity: A clinical review

Antiarrhythmic medications are fundamental in the acute and chronic management of pediatric arrhythmias. Particularly in the pediatric patient population, associated antiarrhythmic toxicities represent important potential adverse effects. Emergency medicine clinicians must be skilled in the detection, workup, and management of antiarrhythmic toxicity. This is a clinical review of the indications, pharmacology, adverse effects, and toxicologic treatment of antiarrhythmics commonly used in the pediatric patient population.

Assessment of the Pharmacokinetics and Pharmacodynamics of Injectable Lidocaine and a Lidocaine-Impregnated Latex Band for Castration and Tail Docking in Lambs

The objectives of this study were to assess the pharmacokinetics and pharmacodynamics of the current standard-of-care for pain mitigation in lambs during castration and tail docking (injectable lidocaine) and assess the ability of Lidocaine-Loaded Bands (LLBs) to deliver therapeutic concentrations into the contacted tissues over time. The study was comprised of four different trials: (1) investigation of in vitro release of lidocaine from LLBs; (2) pharmacokinetics and pharmacodynamics of injectable lidocaine in scrotal and tail tissue; (3) pharmacokinetics and pharmacodynamics of in vivo delivery of lidocaine with LLBs placed on the tail and scrotum of lambs; and (4) a "proof-of-concept" study comparing the sensation of control- versus LLB-banded tail tissue over time. The use of injectable lidocaine provides effective short-term anesthesia for 120 to 180 min following the injection; however, additional strategies are needed to manage long-term pain. The use of an LLB could provide an alternative where tissue lidocaine concentrations meet or exceed the EC50 for at least 21-28 days and, based on electrostimulation data, provides local anesthesia for at least 3 days when compared to a control band. Further studies are needed to compare the use of an injectable local anesthetic to the LLBs.

Topical Delivery Systems Effectively Transport Analgesics to Areas of Localized Pain via Direct Diffusion

Topical delivery systems (TDSs) enable the direct transport of analgesics into areas of localized pain and thus minimize the side effects of administration routes that rely on systemic drug distribution. For musculoskeletal pain, clinicians frequently prescribe topical products containing lidocaine or diclofenac. This study assessed whether drug delivery from a TDS into muscle tissue occurs mainly via direct diffusion or systemic transport. An investigational TDS containing 108 mg lidocaine (SP-103, 5.4% lidocaine), a commercially available TDS containing 36 mg lidocaine (ZTlido®, 1.8% lidocaine), and a topical pain relief gel (Pennsaid®, 2% diclofenac) were tested. Using open flow microperfusion (OFM), interstitial fluid from the dermis, subcutaneous adipose tissue (SAT), and muscle was continuously sampled to assess drug penetration in all tissue layers. Ex vivo and in vivo experiments showed a higher diffusive transport of lidocaine compared to diclofenac. The data showed a clear contribution of diffusive transport to lidocaine concentration, with SP-103 5.4% resulting in a significantly higher lidocaine concentration in muscle tissue than commercially available ZTlido® (p = 0.008). These results indicate that SP-103 5.4% is highly effective in delivering lidocaine into muscle tissue in areas of localized pain for the treatment of musculoskeletal pain disorders (e.g., lower back pain).

Changes in plasma alpha-1 acid glycoprotein following hemorrhagic trauma: Possible role in dose differences of ALM drug therapy in rat and pig resuscitation

INTRODUCTION

The binding of drugs to plasma proteins is an important consideration in drug development. We have reported that the dose of adenosine, lidocaine, and magnesium (ALM) fluid therapy for resuscitation from hemorrhagic shock is nearly 3-times higher for pigs than rats. Since lidocaine strongly binds to serum alpha-1-acid glycoprotein (AGP), the aim of the study was to investigate the effect of hemorrhagic shock on levels of AGP in rats and pigs.

MATERIALS AND METHODS

Healthy adult male Sprague-Dawley rats and female crossbred pigs (n = 33 each) underwent tail vein and peripheral ear vein blood sampling, respectively, to collect plasma for AGP measurements. Rats (n = 17) and pigs (n = 16) underwent surgical instrumentation and uncontrolled hemorrhage via liver resection, and were treated with 3% NaCl ± ALM IV bolus followed 60 min later by 4 h 0.9% NaCl ± ALM IV drip. Rats were monitored for 72 h with blood samples taken post-surgery, and at 5.25, 24, and 72 h. Pigs were monitored for 6 h with blood samples taken post-surgery, and at 60 min and 6 h. Plasma AGP was measured with rat- and pig-specific enzyme-linked immunosorbent assay kits.

RESULTS

Baseline AGP levels in rats were 3.91 μg/mL and significantly 83-fold lower than in pigs (325 μg/mL). Surgical instrumentation was associated with ~10-fold increases in AGP in rats and a 21% fall in pigs. AGP levels remained elevated in rats after hemorrhage and resuscitation (28-29 μg/mL). In contrast, no significant differences in plasma AGP were found in ALM- or Saline-treated pigs over the monitoring period.

CONCLUSIONS

We conclude that the trauma of surgery alone was associated with significant increases in AGP in rats, compared to a contrasting decrease in pigs. Higher levels of plasma AGP in pigs prior to hemorrhagic shock is consistent with the higher ALM doses required to resuscitate pigs compared with rats.

Perioperative intravenous lidocaine for postoperative pain in patients undergoing breast surgery: a meta-analysis with trial sequential analysis of randomized controlled trials

Background

The effectiveness of intravenous lidocaine infusion in managing acute and chronic pain following breast surgery has been a topic of debate. This meta-analysis aims to assess the impact of perioperative intravenous lidocaine on the relief of postoperative pain among patients undergoing breast surgery.

Methods

A systematic search of databases was conducted to identify randomized controlled trials (RCTs) that compared the effects of intravenous lidocaine infusion with placebo or routine care in patients undergoing breast surgery. The primary outcome of interest was the occurrence of chronic post-surgical pain (CPSP) at the longest follow-up. Meta-analyses, incorporating trial sequential analysis, were performed using a random-effects model to assess the overall effect.

Results

A total of twelve trials, involving 879 patients, were included in the analysis. Perioperative intravenous lidocaine demonstrated a significant reduction in the incidence of CPSP at the longest follow-up (risk ratio [RR] 0.62, 95% confidence interval [CI] 0.48-0.81; P = 0.0005; I2 = 6%). Trial sequential analysis (TSA) indicated that the cumulative z curve crossed the trial sequential monitoring boundary for benefit, providing sufficient and conclusive evidence. Furthermore, intravenous lidocaine was associated with decreased opioid consumption and a shorter length of hospital stay.

Conclusion

Perioperative intravenous lidocaine is effective in relieving acute and CPSP in patients undergoing breast surgery.

Systematic review registration

https://inplasy.com/, identifier INPLASY2022100033.

Analgesic efficacy of Intraoperative lidocaine infusion in patients undergoing thyroidectomy

OBJECTIVE

A significant proportion of patients may experience moderate pain requiring treatment in the postoperative first 24 h following thyroidectomy. The aim of this study was to investigate the evaluation of postoperative patient-reported pain from intraoperative intravenous infusion of lidocaine in patients undergoing thyroidectomy surgery.

METHODS

A total of 40 patients with American Society of Anesthesiologists physical status classifications I and II, aged 18-65 years, who were scheduled for elective thyroidectomy with the same indications under general anesthesia at the Ataturk University Medical Faculty's Ear, Nose, and Throat Clinic between November 2019 and February 2020, were divided into two equal groups as randomized and double-blind. Before induction of anesthesia, patients in the lidocaine group were given 1.5 mg/kg lidocaine IV bolus infusion during the operation and until the end of the first postoperative hour, followed by a continuous infusion of 1.5 mg/kg/h. Patients in the control group were given 0.9% isotonic solution according to the same protocol. In the postoperative period, 50 mg of dexketoprofen trometamol was administered and repeated every 12 h. Postoperative pain scores, additional analgesia, and side effects were recorded.

RESULTS

Postoperative pain scores were significantly lower in the lidocaine group (n=20) compared to the control group (n=20) at 30 min and 1st, 2nd, 4th, 8th, and 12th h postoperatively (p < 0.05). Additional analgesia requirements were also significantly lower in the lidocaine group than in the control group (p<0.05).

CONCLUSION

We recommended the use of intravenous lidocaine infusion intraoperatively in thyroidectomy surgery as it reduces pain scores.

LidocAine Versus Opioids In MyocarDial infarction: the AVOID-2 randomized controlled trial

AIMS

Opioid analgesia has been shown to interfere with the bioavailability of oral P2Y12 inhibitors prompting the search for safe and effective non-opioid analgesics to treat ischaemic chest pain.

METHODS AND RESULTS

The lidocAine Versus Opioids In MyocarDial infarction trial was a prospective, Phase II, prehospital, open-label, non-inferiority, randomized controlled trial enrolling patients with suspected STEACS with moderate to severe pain [numerical rating scale (NRS) at least 5/10]. Intravenous lidocaine (maximum dose 300 mg) or intravenous fentanyl (up to 50 µg every 5 min) were administered as prehospital analgesia. The co-primary end points were prehospital pain reduction and adverse events requiring intervention. Secondary end points included peak cardiac troponin I, cardiac MRI (cMRI) assessed myocardial infarct size and clinical outcomes to 30 days. A total of 308 patients were enrolled. The median reduction in pain score (NRS) was 4 vs. 3 in the fentanyl and lidocaine arms, respectively, for the primary efficacy end point [estimated median difference -1 (95% confidence interval -1.58, -0.42, P = 0.5 for non-inferiority, P = 0.001 for inferiority of lidocaine)]. Adverse events requiring intervention occurred in 49% vs. 36% of the fentanyl and lidocaine arms which met non-inferiority and superiority favouring lidocaine (P = 0.016 for superiority). No significant differences in myocardial infarct size and clinical outcomes at 30 days were seen.

CONCLUSION

IV Lidocaine did not meet the criteria for non-inferiority with lower prehospital pain reduction than fentanyl but was safe and better tolerated as analgesia in ST-elevation myocardial infarction (STEMI). Future trials testing non-opioid analgesics in STEMI and whether opioid avoidance improves clinical outcomes are needed.

TRIAL REGISTRATION

CTRN12619001521112p.

The impact of Lidocaine gel on TNF-α expression in surgically induced oral mucosal ulcers: an immunohistochemical analysis in rabbits

Background: Besides being a local anesthetic agent lidocaine is a promising anti-inflammatory agent with limited studies on its effect on the mucosa. Aim: Assess the anti-inflammatory effect of lidocaine following surgical induction wound in the oral mucosa as assessed by tumor necrosis factor-α (TNF-α) expression. Materials and methods: The study was conducted on 32 albino rabbits that were categorized into 2 equal groups of 16 rabbits: In the control group an oral wound was surgically induced and left without treatment and in the treatment group an oral wound was surgically induced and received topical Lidocaine gel. Euthanasia of animals was carried out on days 1, 3, 7, and 10, and sample sites were processed for histopathological and immunohistochemical staining for TNF-α. Results: In the histological observations, it was noticed that the healing process was more rapid and convenient in the test group compared to the control group. For Immunohistochemical assessment, the TNF-α started to express clearly at 1 day and gradually decreased and disappeared at 10 days with a superior effect of the lidocaine group over the control group. Conclusion: Lidocaine seems to have anti-inflammatory reactions by lowering TNF-α levels and preventing the production of pro-inflammatory cytokines.

Safety of Lidocaine During Wide-Awake Local Anesthesia No Tourniquet for Distal Radius Plating

Purpose

This study evaluated the clinical and biochemical safety profile of infiltration of lidocaine with adrenaline in wide-awake local anesthesia no tourniquet for distal radius plating.

Methods

Twenty-four participants were randomly assigned to the therapeutic group (n = 19) (1% lidocaine in 1:100,000 adrenaline) and control group (n = 5) (2% lidocaine alone). Clinical parameters, including skin necrosis, duration of recovery of sensation, and lidocaine toxicity, were monitored. The serum lidocaine level was measured at different time intervals using a high-performance liquid chromatography reagent.

Results

No lidocaine toxicity was recorded in any participant. The therapeutic group had a longer time for recovery of sensation. There was a significant difference in the serum lidocaine levels between both the groups at all time intervals up to 6 hours, with all participants exhibiting serum lidocaine levels below the mild toxicity level of 6.0 μg/mL.

Conclusions

Lidocaine used within a safe recommended dose in wide-awake local anesthesia no tourniquet for distal radius plating is clinically and biochemically safe.

Clinical relevance

Determining the clinical and biochemical safety profile of lidocaine with adrenaline in wide-awake local anesthesia no tourniquet can promote wider use of this technique.

Genicular nerve block in juvenile idiopathic arthritis: a randomized clinical trial

OBJECTIVES

This study aimed at evaluating the effect of genicular nerve block (GNB) in juvenile idiopathic arthritis (JIA) patients with persistent unilateral knee arthritis on pain, inflammatory parameters, function, and range of motion.

METHODS

A total of 104 JIA patients were diagnosed according to the International League Against Rheumatism (ILAR) criteria with persistent unilateral knee arthritis. They were allocated randomly into 2 groups: group 1 treated with GNB, while group 2 was treated with intra-articular triamcinolone (TA) only. Visual analogue scale (VAS) on pain, sonography of large joints in rheumatology (SOLAR) scoring system, and Lysholm scores were assessed at 0-, 2-, and 12-week intervals. Swelling and tenderness were clinically evaluated semi-quantitatively (0-3) at the same time intervals.

RESULTS

VAS pain, tenderness, swelling, and SOLAR grey scale (GS) and power Doppler (PD) scores were significantly reduced after 2 weeks in both groups (p < 0.05). This was greater in the GNB group regarding VAS and tenderness, while SOLAR and swelling were stronger reduced in TA group. After 12 weeks, all outcome measures showed lower values in the GNB group compared to TA, and this was significant regarding VAS pain. Moreover, Lysholm functional score was significantly increased in both groups at both intervals; and higher values were seen in the TA group compared to GNB after 2 weeks.

CONCLUSION

GNB was able to control pain and improve function and inflammation of the knee joint in JIA patients. Though steroid attained better results after 2 weeks, GNB achieved an equivalent longer-term improvement after 12 weeks.

TRIAL REGISTRATION IDENTIFYING NUMBER

NCT04687930. Key Points • Persistent knee arthritis treatment in JIA is always challenging. • GNB was approved for treatment of pain in knee osteoarthritis. • GNB in the present study succeeded to control active knee arthritis and this effect was comparable to intra-articular steroid injection.

Perioperative intravenous lidocaine use in children

Perioperative pain management impacts patient morbidity, quality of life, and hospitalization cost. In children, it impacts not only the child, but the whole family. Adjuncts for improved perioperative analgesia continue to be sought to minimize adverse side effects associated with opioids and for those in whom regional or neuraxial anesthesia is not suitable. The use of ketamine and alpha agonists may be useful in these settings but have noted adverse effects including hallucinations, hemodynamic instability, and excessive sedation. One alternative is intravenous lidocaine. Despite its off-label use, intravenous lidocaine has demonstrated anti-neuropathic, anti-hyperalgesic, and anti-inflammatory actions and is an emerging technique. Multiple studies in adults have demonstrated beneficial effects of perioperative intravenous lidocaine including improved perioperative analgesia with reduced postoperative opioid use, improved gastrointestinal function, earlier mobilization, and reduction in hospital length of stay. Despite the limited pediatric literature, some of these findings have been replicated. Large-scale trials providing evidence for the pediatric pharmacokinetics and high-quality safety data with respect to intravenous lidocaine are still however lacking. To date, dose ranges studied in the pediatric population have not been associated with serious side effects and current data suggests perioperative intravenous lidocaine in a subgroup of pediatric surgical patients seems well-tolerated and beneficial.

Comparing Efficacy of Intravenous Dexmedetomidine and Lidocaine on Perioperative Analgesic Consumption in Patients Undergoing Laparoscopic Surgery

Background

Perioperative pain management is a major challenge for anaesthesiologists. IV lidocaine and dexmedetomidine have been utilised for peri-operative pain management.

Aims and Objectives

To analyse the effects of intraoperative intravenous lignocaine/dexmedetomidine on pain relief, opioid consumption, peri-operative hemodynamic and side-effect profiles/unique interactions in patients undergoing laparoscopic surgeries.

Materials and Methods

Prospective, interventional, single-centric, double-blind, randomised, active-controlled, Helsinki protocol-compliant clinical study was conducted on 90 ASA I/II class patients aged 18-60 yrs. This Patients were block-randomised to Group-L (2% Lignocaine), Group-D (dexmedetomidine) and Group C (Control/Placebo/0.9% normal saline). Hemodynamic were noted at pre-defined time frames intra-/post-operatively. Post-operative VAS score and Richmond Agitation Sedation Score monitoring was done.

Results

Demographic parameters of were comparable. Mean intra-operative fentanyl consumption amongst the three groups were 20.5 ± 20.05 mcg, 26.5 ± 17.57 mcg and 46.83 + 21.31 mcg (Group-L, Group-D, Group-C; P value Group-L vs Group-D:0.22, Group L/D vs Group C: <0.0001). Group-D exhibited the lower heart rates and MAP (P < 0.05). Extubation- First rescue analgesic phase was comparable for the Group-C and Group-L (59.17 ± 46.224 min vs 61.64 ± 53.819 min) and significantly greater in Group-D (136.07 + 55.350 min; P < 0.0001).

Conclusion

Both Dexmedetomidine and lignocaine can be useful intra-operative pain relief adjuncts. Dexmedetomidine delayed First rescue analgesic and total analgesic consumption more than lignocaine. Dexmedetomidine patients exhibited bradycardia intraoperatively more than the other groups. we recommend, Dexmedetomidine in the intra-operative phase and lignocaine in the post-operative phase can be an alternative in patients who are poor candidates for post-operative opioids/sedation/contraindicated regional anaesthesia regimes.

The Use of Intravenous Lidocaine in Perioperative Medicine: Anaesthetic, Analgesic and Immune-Modulatory Aspects

This narrative review provides an update on the applied pharmacology of lidocaine, its clinical scope in anaesthesia, novel concepts of analgesic and immune-modulatory effects as well as the current controversy around its use in perioperative opioid-sparing multi-modal strategies. Potential benefits of intravenous lidocaine in the context of cancer, inflammation and chronic pain are discussed against concerns of safety, toxicity and medico-legal constraints.

Prophylactic intra-arterial injection of lidocaine: a novel strategy to prevent endovascular embolization-induced trigeminocardiac reflex

BACKGROUND

Trigeminocardiac reflex (TCR) is a brainstem reflex that can lead to hemodynamic instability manifested as bradycardia, decrease/increase of mean arterial pressure (MAP) and, in the worst case scenario, asystole during surgery. The effective intraoperative management of recurrent and profound TCR has yet to be established. This randomized paired study was performed to identify the effect of a prophylactic intra-arterial injection of lidocaine to prevent TCR caused by Onyx embolization during cerebrovascular intervention surgery.

METHODS

A total of 136 patients who received Onyx embolization under general anesthesia were assigned to a control group pretreated with intra-arterial saline injection or a lidocaine group pretreated with an intra-arterial injection of 20 mg lidocaine. Heart rate (HR) and MAP were closely monitored during the embolization procedures and the incidence of TCR, mainly characterized by a decrease in HR of ≥20%, and perioperative adverse events was recorded.

RESULTS

During dimethyl sulfoxide (DMSO)/Onyx injection, HR was much slower in the control group than in the lidocaine group (p<0.05). TCR occurred in 12 patients (17.6%) in the control group (cardiac arrest in 3 patients) with decreased (7 cases) or increased (5 cases) MAP, whereas no TCR was observed in the lidocaine group. Notably, most TCR episodes occurred in patients with dural arteriovenous fistula and middle meningeal artery being affected. The composite adverse events were significantly higher in the control group than in the lidocaine group (p<0.05).

CONCLUSION

This prospective study shows that a prophylactic intra-arterial injection of 20 mg lidocaine could be recommended as a novel strategy to effectively and safely prevent TCR during endovascular embolization.

A Randomized Controlled Trial Comparing Intravenous Lidocaine Infusion With Thoracic Epidural for Perioperative Analgesia and Quality of Recovery After Surgery in Laparoscopic Left-Sided Colon and Sphincter-Sparing Rectal Resection Surgery

Background Protocols for Enhanced Recovery after Surgery (ERAS) have been constantly evolving, and the best method of managing perioperative pain, especially in laparoscopic surgeries, is still debatable. The primary goal of these protocols is to steer toward opioid-sparing analgesia. Intravenous lidocaine, which has both analgesic and anti-inflammatory properties, may improve the overall recovery of patients. Objectives The aim of this randomized controlled trial was to compare the efficacy of intravenous lidocaine infusion (IVL) with thoracic epidural analgesia (TEA) in the management of perioperative pain and recovery in the laparoscopic left-sided colon and sphincter-sparing rectal surgery. Methods In this study, 37 patients were randomized to either the IVL group or the TEA group. IVL infusion was started before the surgical incision and stopped 30 minutes after transferring the patient to the postanesthesia care unit (PACU). Postoperative pain scores, opioid consumption, rescue analgesic doses, quality of recovery scores, time to discharge, and adverse events were recorded prospectively. Data were analyzed using two independent sample t-test and paired t-test, with p < 0.05 taken as statistically significant. Results The mean difference of overall NRS (numerical rating scale) pain scores in the ward was significantly higher in the IVL group as compared to the TEA group, which was 3.58 (2.29) vs 2.23 1.95) (p < 0.001). The IVL group required more mean rescue opioid boluses than the TEA group, which was 11.36 (8.684) vs 5.96 (6.215) (p < 0.001). However, both IVL and TEA groups had similar pain scores intraoperatively and in the PACU. Conclusions TEA provides better analgesia and decreased opioid requirements compared to intravenous lidocaine during the 24-hour period in the ward after laparoscopic left-sided colon and sphincter-sparing rectal surgery, although there was no difference in the quality of recovery between IVL and TEA groups.

Stability of dilutions of methadone alone, and in combination with lidocaine and ketamine

OBJECTIVES

To assess stability and degradation over time, of methadone alone, and mixed with lidocaine and ketamine, using various diluents and storage conditions.

MATERIALS AND METHODS

Solutions of methadone diluted in 0.9% NaCl, and methadone-lidocaine-ketamine diluted in 0.9% NaCl or Hartmann's solution, and stored at room temperature with exposure to light, or refrigerated at 4°C and protected from light, were maintained over 10 days. Chemical stability was determined using liquid chromatography immediately after preparation and following 4, 24, 48, 96 and 240 hours of storage. Physical stability of the solutions was evaluated by visual examination and absorbance of ultraviolet/visible light. A linear model assessed the impact of different diluent solutions and storage conditions on drug degradation over time.

RESULTS

There was no evidence of physicochemical incompatibility for any solution. Methadone concentration, when diluted alone or in methadone-lidocaine-ketamine with Hartmann's solution at 4°C, did not decline over time. Ketamine and lidocaine decreased to a similar extent over time, regardless of the diluent used or storage method, while methadone in methadone-lidocaine-ketamine diluted with 0.9% NaCl or with Hartmann's solution at room temperature exposed to light, also declined over time; however, all three methadone-lidocaine-ketamine components retained acceptable stability (<10% degradation) for at least 48 hours following preparation, irrespective of diluent or storage conditions.

CLINICAL SIGNIFICANCE

Regardless of the diluent or storage method, methadone-lidocaine-ketamine solutions degrade over time, but this only becomes clinically significant after 48 hours. Solutions of 1 mg/ml methadone in 0.9% NaCl are stable for at least 10 days under storage conditions likely to be encountered in general practice.

Tutorial on Clinical Practice for Use of the Fiberoptic Endoscopic Evaluation of Swallowing Procedure With Adult Populations: Part 1

PURPOSE

Representatives of the American Board of Swallowing and Swallowing Disorders (AB-SSD) and American Speech-Language-Hearing Association (ASHA) Special Interest Group (SIG) 13: Swallowing and Swallowing Disorders (Dysphagia) developed this tutorial to identify and recommend best practice guidelines for speech-language pathologists who conduct and interpret fiberoptic endoscopic evaluation of swallowing (FEES) procedures in adults. This document also includes proposed training needs and methods for achieving competency. Expert opinion is provided regarding indications for performing the FEES exam, potential contraindications, adverse effects and safety, equipment and personal protection, the exam protocol, interpretation and documentation of findings, and training requirements to perform and interpret the exam.

CONCLUSIONS

This tutorial by the AB-SSD and SIG 13 represents the first update about the FEES procedure since ASHA's position paper and technical report published in 2004. Creation of this document by members of the AB-SSD and SIG 13 is intended to guide professionals who are training for or practicing FEES in the adult population toward established best practices and the highest standards of care.

Evaluation of Cyclooxygenase-2 and p53 Expression in Pterygium Tissue Following Preoperative Intralesional Ranibizumab Injection

Introduction: Overexpression of vascular endothelial growth factor (VEGF), cyclooxygenase-2 (COX-2), and p53 are the postulated aetiopathogenesis in pterygium. VEGF is responsible for the induction of COX-2 expression, whereas p53 plays an important role in the regulation of VEGF. This study aimed to evaluate the immunohistochemistry of COX-2 and p53 expressions from excised pterygium tissue from patients who received intralesional ranibizumab (anti-VEGF) injection 2 weeks prior to pterygium surgery. Materials and Methods: An interventional comparative study involving patients presenting with primary pterygium was conducted between September 2015 and November 2017. The patients were randomized into either the intervention or control group. Patients in the intervention group were injected with intralesional ranibizumab (0.5 mg/0.05 ml) 2 weeks prior to surgery. Both groups underwent pterygium excision followed by conjunctival autograft. Immunohistochemistry staining was performed to evaluate COX-2 and p53 expressions in the excised pterygium tissue. Results: A total of 50 patients (25 in both the intervention and control groups) were recruited. There were 34 (68%) patients with grade III pterygium and 16 (32%) patients with grade IV pterygium. There was statistically significant difference in reduction of COX-2 expression in the epithelial layer [84.0% (95% CI: 63.9, 95.5)] (p = 0.007) and stromal layer [84.0% (95% CI: 63.9, 95.5)] (p < 0.001) between intervention and control groups. There was no significant difference in the reduction of p53 expression between the two groups. Conclusion: This study demonstrated the possible use of intralesional anti-VEGF treatment prior to pterygium excision as a potential future modality of adjunctive therapy for pterygium surgery.

Tenons Patch Graft: A Review of Indications, Surgical Technique, Outcomes and Complications

PURPOSE

Corneal perforations are common corneal emergencies faced by ophthalmologists across the globe. There are multiple modalities of management, most of which require an eye bank support or availability of tissue adhesives. Tenons patch graft (TPG) is a technique that does not depend on these factors as the graft is harvested from the same eye of the patient. The aim of this review is to provide an overview of the indications, technique, normal postoperative course, and management of complications.

METHODS

After carrying out a literature search on "tenons capsule", "corneal patch graft", "tenons patch graft", "multilayered amniotic membrane" and "corneal perforations", 28 articles were included for this review.

RESULTS

TPG graft can be performed in cases of small to moderate perforations without active suppuration. The procedure can also be combined with amniotic membrane grafting or tissue adhesives to provide additional tectonic support. Postoperatively, the epithelium heals over a course 2-3 weeks and restoration of a stable ocular surface with a corneal scar is completed by the third postoperative month. Complications following the surgical procedure are rare but can include graft displacement, melt and pseudoectasia. Subsequent visual rehabilitation with contact lenses or keratoplasties can be planned in these eyes that yields good visual outcomes.

CONCLUSIONS

Tenons patch graft is a simple yet viable option in management of small to moderate corneal perforations. The procedure does not necessitate the prior availability of specialized products and can be performed with routine equipment of an ophthalmic theatre, making it an attractive option in low resource settings.

Pharmacological prevention of renal ischemia-reperfusion injury in a rat model

INTRODUCTION

Renal ischemia-reperfusion injury (IRI) can lead to significant morbidity and mortality. It remains a leading cause of acute kidney injury and is therefore an important issue in trauma and renal transplant surgery. Various pharmaceutical agents have been used in an attempt to dampen the harmful effects of IRI but few have been shown to be useful clinically. Riluzole, Lidocaine and Lamotrigine have been demonstrated to show anti-ischaemic properties in other organs; however, their use has not been tested in the kidneys. We investigated Riluzole, Lidocaine and Lamotrigine for their preventive effects of renal IRI using a rat model.

METHODS

Winstar rats (n = 48) were divided into four groups (n = 12 per group)-three treatment groups and one control group. Riluzole, Lidocaine and Lamotrigine were given prior to renal ischemia only (IO) or IRI. The degree of ischemia was measured by glutathione levels and a TUNEL assay was used to measure DNA fragmentation.

RESULTS

Riluzole, Lidocaine and Lamotrigine pre-treatment each resulted in statistically higher glutathione levels compared to controls (P = 0.002; P = 0.007 and P = 0.005, respectively). Riluzole and Lidocaine were also effective at preventing depletion of glutathione following IO (P = 0.007 and P = 0.014 respectively), while Lamotrigine was ineffective in IO (P = 0.71). The degree of DNA fragmentation seen on the TUNEL assay was markedly reduced in all three-drug groups in both IO and IRI.

DISCUSSION

Riluzole, Lidocaine and Lamotrigine all have anti-ischaemic effects in the rat kidney and can have potential therapeutic implications.

The impact of cigarette smoking on the efficiency of local anesthesia during simple tooth extraction

Smoking is harmful to all organs of the human body and can affect nerve response to local anesthesia.

This study aimed to determine the effect of cigarette smoking on the amount and onset of local anesthesia, as well as the chief complaint (symptomatic and asymptomatic), number of cigarettes, and duration of smoking.

Materials and methods

A selective clinical case-control study carried out at the Oral Surgery Clinic of the Teaching Hospital at the College of Dentistry. One hundred and three male patients participated in the study, and they were divided into two groups (55 smokers and 48 nonsmokers). The patients received a local anesthetic agent (2% Lidocaine) in a 1.8 ml dental cartridge. The number of cartridges and the onset time of local anesthesia were detailed for each patient in a special case sheet prepared for this study.

Results

There was a statistically significant difference between the smoker and nonsmoker groups regarding the amount of local anesthetic solution (p = .041) with a higher amount needed in the smoker group; however, the onset of action showed no significant difference between the two groups (p = 0.983). The symptomatic cases in smokers needed a higher amount of local anesthesia than the asymptomatic cases with a statistically significant difference (p = 0.002). There was no relationship between daily cigarette consumption and the amount of local anesthetic solution (p = .054) and also the onset of local anesthesia (p = .938). The duration of smoking has no significant relationship with onset time (p = .480) and the amount of local anesthesia (p = .418).

Conclusion

The amount of local anesthesia used in smoker patients was higher than that in nonsmoker patients, especially if there were symptoms like pain. The duration of smoking and daily cigarette consumption had no effect on the amount and the onset of local anesthesia.

A novel definition and treatment of hyperinflammation in COVID-19 based on purinergic signalling

Hyperinflammation plays an important role in severe and critical COVID-19. Using inconsistent criteria, many researchers define hyperinflammation as a form of very severe inflammation with cytokine storm. Therefore, COVID-19 patients are treated with anti-inflammatory drugs. These drugs appear to be less efficacious than expected and are sometimes accompanied by serious adverse effects. SARS-CoV-2 promotes cellular ATP release. Increased levels of extracellular ATP activate the purinergic receptors of the immune cells initiating the physiologic pro-inflammatory immune response. Persisting viral infection drives the ATP release even further leading to the activation of the P2X7 purinergic receptors (P2X7Rs) and a severe yet physiologic inflammation. Disease progression promotes prolonged vigorous activation of the P2X7R causing cell death and uncontrolled ATP release leading to cytokine storm and desensitisation of all other purinergic receptors of the immune cells. This results in immune paralysis with co-infections or secondary infections. We refer to this pathologic condition as hyperinflammation. The readily available and affordable P2X7R antagonist lidocaine can abrogate hyperinflammation and restore the normal immune function. The issue is that the half-maximal effective concentration for P2X7R inhibition of lidocaine is much higher than the maximal tolerable plasma concentration where adverse effects start to develop. To overcome this, we selectively inhibit the P2X7Rs of the immune cells of the lymphatic system inducing clonal expansion of Tregs in local lymph nodes. Subsequently, these Tregs migrate throughout the body exerting anti-inflammatory activities suppressing systemic and (distant) local hyperinflammation. We illustrate this with six critically ill COVID-19 patients treated with lidocaine.

Effects of lignocaine vs. opioids on antiplatelet activity of ticagrelor: the LOCAL trial

AIMS

We assessed the impact of intravenous fentanyl and lignocaine on the pharmacokinetics and pharmacodynamics of ticagrelor in patients with unstable angina and non-ST-elevation myocardial infarction and their procedural analgesic efficacy and safety.

METHODS AND RESULTS

Seventy patients undergoing coronary angiography with ticagrelor loading were included in the pharmacokinetic and pharmacodynamic analyses of this randomized trial. Plasma ticagrelor levels 2 h post-loading dose were significantly lower in the fentanyl arm than in the lignocaine treatment arm (598 vs. 1008 ng/mL, P = 0.014). The area under the plasma-time curves for ticagrelor (1228 vs. 2753 ng h/mL, P < 0.001) and its active metabolite (201 vs. 447 ng h/mL, P = 0.001) were both significantly lower in the fentanyl arm. Expression of activated platelet glycoprotein IIb/IIIa receptor (2829 vs. 1426 mean fluorescence intensity, P = 0.006) and P-selectin (439 vs. 211 mean fluorescence intensity, P = 0.001) was significantly higher at 60 min in the fentanyl arm. A higher proportion of patients had high on-treatment platelet reactivity in the fentanyl arm at 60 min using the Multiplate Analyzer (41% vs. 9%, P = 0.002) and 120 min using the VerifyNow (30% vs. 3%, P = 0.003) and VASP (37% vs. 6%, P = 0.002) assays. Both drugs were well tolerated with a high level of patient satisfaction.

CONCLUSIONS

Unlike fentanyl, lignocaine does not impair the bioavailability or delay the antiplatelet effect of ticagrelor. Both drugs were well tolerated and effective with a high level of patient satisfaction for procedural analgesia. Routine procedural analgesia during percutaneous coronary intervention should be reconsidered and if performed, lignocaine is a beneficial alternative to fentanyl.

Preparation and In Vivo Evaluation of a Lidocaine Self-Nanoemulsifying Ointment with Glycerol Monostearate for Local Delivery

Lidocaine, a commonly used local anesthetic, has recently been developed into a number of ointment products to treat hemorrhoids. This study examined its efficient delivery to the dermis through the pharmaceutical improvement of hemorrhoid treatment ointments. We attempted to increase the amount of skin deposition of lidocaine by forming a nanoemulsion through the self-nanoemulsifying effect that occurs when glycerol monostearate (GMS) is saturated with water. Using Raman mapping, the depth of penetration of lidocaine was visualized and confirmed, and the local anesthetic effect was evaluated via an in vivo tail-flick test. Evaluation of the physicochemical properties confirmed that lidocaine was amorphous and evenly dispersed in the ointment. The in vitro dissolution test confirmed that the nanoemulsifying effect of GMS accelerated the release of the drug from the ointment. At a specific concentration of GMS, lidocaine penetrated deeper into the dermis; the in vitro permeation test showed similar results. When compared with reference product A in the tail-flick test, the L5 and L6 compounds containing GMS had a significantly higher anesthetic effect. Altogether, the self-nanoemulsifying effect of GMS accelerated the release of lidocaine from the ointment. The compound with 5% GMS, the lowest concentration that saturated the dermis, was deemed most appropriate.

Molecular mechanisms of lidocaine

Lidocaine is an amide-class local anesthetic used clinically to inhibit pain sensations. Systemic administration of lidocaine has antinociceptive, antiarrhythmic, anti-inflammatory, and antithrombotic effects. Lidocaine exerts these effects under both acute and chronic pain conditions and acute respiratory distress syndrome through mechanisms that can be independent of its primary mechanism of action, sodium channel inhibition. Here we review the pathophysiological underpinnings of lidocaine's role as an anti-nociceptive, anti-inflammatory mediated by toll-like receptor (TLR) and nuclear factor kappa-β (NF-kβ) signalling pathways and downstream cytokine effectors high mobility group box 1 (HMGB1) and tumour necrosis factor-α (TNF-α).

Perioperative Intravenous Lidocaine and Metastatic Cancer Recurrence - A Narrative Review

Cancer is a major global health problem and the second leading cause of death worldwide. When detected early, surgery provides a potentially curative intervention for many solid organ tumours. Unfortunately, cancer frequently recurs postoperatively. Evidence from laboratory and retrospective clinical studies suggests that the choice of anaesthetic and analgesic agents used perioperatively may influence the activity of residual cancer cells and thus affect subsequent recurrence risk. The amide local anaesthetic lidocaine has a well-established role in perioperative therapeutics, whether used systemically as an analgesic agent or in the provision of regional anaesthesia. Under laboratory conditions, lidocaine has been shown to inhibit cancer cell behaviour and exerts beneficial effects on components of the inflammatory and immune responses which are known to affect cancer biology. These findings raise the possibility that lidocaine administered perioperatively as a safe and inexpensive intravenous infusion may provide significant benefits in terms of long term cancer outcomes. However, despite the volume of promising laboratory data, robust prospective clinical evidence supporting beneficial anti-cancer effects of perioperative lidocaine treatment is lacking, although trials are planned to address this. This review provides a state of the art summary of the current knowledge base and recent advances regarding perioperative lidocaine therapy, its biological effects and influence on postoperative cancer outcomes.

Biorelevant In Vitro Skin Permeation Testing and In Vivo Pharmacokinetic Characterization of Lidocaine from a Nonaqueous Drug-in-Matrix Topical System

Recently, lidocaine topical systems utilizing nonaqueous matrices have been developed and provide efficient lidocaine delivery through the skin, such that lower concentrations of drug provide equivalent or greater drug delivery than drug-in-matrix hydrogel lidocaine patches. This study characterizes drug delivery from a nonaqueous lidocaine topical system with increasing drug load both in vitro and in vivo. Topical systems formulated with either 1.8% or 5.4% lidocaine were applied to healthy volunteers' backs (n = 15) for 12 h in a single-center, open-label, four-treatment, four-period crossover pharmacokinetic study. Subjects were dosed with either three 1.8% systems or one, two, or three 5.4% systems in each period. Blood was collected for up to 48 h, and plasma lidocaine levels were measured with a validated HPLC method. In parallel, human and mouse skin models characterized the in vitro skin permeation profile. The pharmacokinetic profile was linear between one, two, and three lidocaine 5.4% applications. Application of three lidocaine 1.8% systems (108 mg lidocaine) was bioequivalent to one lidocaine 5.4% system (108 mg lidocaine). Both topical systems remained well adhered to the skin and irritation was mild. The 5.4% system had approximately threefold higher skin permeability than the 1.8% system in the mouse and human skin models. The results indicate increasing the drug load by three times results in triple the drug delivery both in vivo and in vitro. The relationship between the in vitro permeation and in vivo absorption correlates and is nonlinear.

Facile design of lidocaine-loaded polymeric hydrogel to persuade effects of local anesthesia drug delivery system: complete in vitro and in vivo toxicity analyses

The principal goal of the present investigation was to enterprise new and effective drug delivery vesicle for the sustained delivery of local anesthetic lidocaine hydrochloride (LDC), using a novel combination of copolymeric hydrogel with tetrahydroxyborate (COP–THB) to improve bioactivity and therapeutic potential. To support this contention, the physical and mechanical properties, rheological characteristics, and component release of candidate formulations were investigated. An optimized formulation of COP–THB containing LDC to an upper maximum concentration of 1.5% w/w was assessed for drug crystallization. The biocompatibility of the prepared COP–THB hydrogel was exhibited strong cell survival (96%) and growth compatibility on L929 fibroblast cell lines, which was confirmed by using methods of MTT assay and microscopic observations. The COP–THB hydrogel release pattern is distinct from that of COP–THB/LDC hydrogels by the slow-release rate and the low percentage of cumulative release. In vivo evaluations were demonstrated the anesthetic effects and toxicity value of treated samples by using mice models. In addition, COP–THB/LDC hydrogels significantly inhibit in vivo tumor growth in mice model and effectively reduced it is in vivo toxicity. The pharmacological evaluation showed that encapsulation of LDC in COP–THB hydrogels prolonged its anesthetic action with favorable in vitro and in vivo compatibility. This novel design may theoretically be used in promising studies involving the controlled release of local anesthetics.

Highlights

Development a modified sustained release system for the local anesthetic lidocaine.

PVP-THB hydrogel to improve the pharmacological properties of the drug and their anesthetic activities.

Profiles of PVP-THB/LDC showed that the effective release of associated lidocaine.

This new formulation could potentially be used in future local anesthetics.

Fabrication of Alginate-Based O/W Nanoemulsions for Transdermal Drug Delivery of Lidocaine: Influence of the Oil Phase and Surfactant

Transdermal drug delivery of lidocaine is a good choice for local anesthetic delivery. Microemulsions have shown great effectiveness for the transdermal transport of lidocaine. Oil-in-water nanoemulsions are particularly suitable for encapsulation of lipophilic molecules because of their ability to form stable and transparent delivery systems with good skin permeation. However, fabrication of nanoemulsions containing lidocaine to provide an extended local anesthetic effect is challenging. Hence, the aim of this study was to address this issue by employing alginate-based o/w nanocarriers using nanoemulsion template that is prepared by combined approaches of ultrasound and phase inversion temperature (PIT). In this study, the influence of system composition such as oil type, oil and surfactant concentration on the particle size, in vitro release and skin permeation of lidocaine nanoemulsions was investigated. Structural characterization of lidocaine nanoemulsions as a function of water dilution was done using DSC. Nanoemulsions with small droplet diameters (d < 150 nm) were obtained as demonstrated by dynamic light scattering (DLS) and cryo-TEM. These nanoemulsions were also able to release 90% of their content within 24-h through PDMS and pig skin and able to the drug release over a 48-h. This extended-release profile is highly favorable in transdermal drug delivery and shows the great potential of this nanoemulsion as delivery system.

An open-label, non-inferiority randomized controlled trial of lidocAine Versus Opioids In MyocarDial Infarction study (AVOID-2 study) methods paper

Background There is increasing evidence that opioids interfere with the oral bioavailability of P2Y₁₂ inhibitors leading to delayed onset of antiplatelet effects. Several strategies have been proposed to mitigate this interaction including utilizing alternative analgesic agents in the management of ischemic chest pain. Methods The lidocAine Versus Opioids In MyocarDial Infarction (AVOID-2) study is a phase II, pre-hospital, open-label, non-inferiority, randomized controlled trial conducted by Ambulance Victoria and Monash University in metropolitan Melbourne, Victoria, Australia. The purpose of the study is to compare the analgesic effect (reduction in pain by arrival to hospital) and safety (e.g. adverse drug reactions) (co-primary endpoints) of intravenous lidocaine versus intravenous fentanyl in 300 adult patients attended by ambulance with suspected ST-elevation myocardial infarction (STEMI). Secondary endpoints and a cardiac magnetic resonance imaging (MRI) sub-study will also compare infarct size between these two groups. Conclusions The evaluation of alternative analgesic agents in the management of acute coronary syndromes is urgently needed to manage the opioid-P2Y₁₂ inhibitor interaction. The results of this trial will have significant implications on the emergency management of acute coronary syndromes internationally.

Lidocaine Continuous Subcutaneous Infusion for Neuropathic Pain in Hospice Patients: Safety and Efficacy

Lidocaine continuous subcutaneous infusion (L-CSCI) for neuropathic pain in hospice patients has limited evidence for its safety and efficacy, and guidelines are lacking. This study assesses a series of patients admitted to a hospice over a six-month period that had neuropathic pain and received L-CSCI. The primary outcome was improvement in patient-rated distress from pain following L-CSCI titration. Also assessed were changes in oral morphine equivalent dose (OME), frequency of breakthrough medication, functional status, adverse effects and perception of response. Fifteen patients received L-CSCI for an average of 6.7 days (range 1-92). Average pain distress score decreased by 2 or more in six patients. Positive responses to L-CSCI were documented in the clinical notes of 10 patients. Opioid down-titration occurred in four patients. Lidocaine levels were performed in 3 patients but did not change management. Five patients experienced adverse effects attributable to lidocaine and all responded to simple measures. In conclusion, L-CSCI can help manage neuropathic pain in hospice patients, particularly in those who cannot swallow oral medications. Further systematic research is warranted to establish efficacy and tolerability, and to inform guideline development.

Metabolic N-Dealkylation and N-Oxidation as Elucidators of the Role of Alkylamino Moieties in Drugs Acting at Various Receptors

Metabolic reactions that occur at alkylamino moieties may provide insight into the roles of these moieties when they are parts of drug molecules that act at different receptors. N-dealkylation of N,N-dialkylamino moieties has been associated with retaining, attenuation or loss of pharmacologic activities of metabolites compared to their parent drugs. Further, N-dealkylation has resulted in clinically used drugs, activation of prodrugs, change of receptor selectivity, and providing potential for developing fully-fledged drugs. While both secondary and tertiary alkylamino moieties (open chain aliphatic or heterocyclic) are metabolized by CYP450 isozymes oxidative N-dealkylation, only tertiary alkylamino moieties are subject to metabolic N-oxidation by Flavin-containing monooxygenase (FMO) to give N-oxide products. In this review, two aspects will be examined after surveying the metabolism of representative alkylamino-moieties-containing drugs that act at various receptors (i) the pharmacologic activities and relevant physicochemical properties (basicity and polarity) of the metabolites with respect to their parent drugs and (ii) the role of alkylamino moieties on the molecular docking of drugs in receptors. Such information is illuminative in structure-based drug design considering that fully-fledged metabolite drugs and metabolite prodrugs have been, respectively, developed from N-desalkyl and N-oxide metabolites.

Topical Application of Lidocaine and Bupivacaine to Disbudding Wounds in Dairy Calves: Safety, Toxicology and Wound Healing

Simple Summary

Disbudding is a common, but painful procedure performed on calves to prevent horn growth. Tri-Solfen^® is a combination local anaesthetic and antiseptic formulation which, applied topically to the disbudding wound, is reported to reduce calf pain. Applied in this manner, the local anaesthetics in Tri-Solfen^®, lidocaine and bupivacaine, are reported to be poorly absorbed, resulting in low risk of neurological or cardiotoxic effects. The potential impacts on other blood, urine and tissue parameters and on wound healing when used in this manner, and/or accidental overdose situations are unknown, however. We performed experiments investigating (i) the safety of Tri-Solfen^® (including overdose situations) and (ii) the impact of Tri-Solfen^® on disbudding wound healing under field conditions. No adverse health effects were observed in Tri-Solfen^®-treated animals, even those receiving 5× the recommended dose, with no clinically significant differences in measured parameters between placebo and Tri-Solfen^® groups. No negative impacts on wound healing were noted. Conversely, lower levels of bacterial wound colonisation were evident, and there was reduced incidence of abnormal wounds at days 11–12 in Tri-Solfen^®-treated animals.

Abstract

Tri-Solfen^® is a combination topical anaesthetic and antiseptic solution containing lidocaine, bupivacaine, adrenaline and cetrimide. Applied to wounds, it is reported to reduce the pain experienced by calves following thermocautery disbudding. While lidocaine and bupivacaine are widely used in medicine, conflicting data exist on the impact of these compounds when applied directly to the surgical wound. To investigate the safety of Tri-Solfen^® applied to thermocautery disbudding wounds of calves, experiments were performed to measure (i) the safety of Tri-Solfen^® (including in overdose situations); and (ii) the impact of Tri-Solfen^® application at recommended doses on disbudding wound healing under field conditions. Haematological, biochemical and urinalysis parameters did not show clinically significant differences between placebo and Tri-Solfen^® groups (1×, 3× and 5× dose). No adverse health impacts were reported. Histopathological analysis of wounds noted a reduction in bacterial colonies in Tri-Solfen^®-treated wounds. Under field conditions, no negative impacts on wound healing were noted. Conversely, there was reduced incidence of abnormal wounds, with an associated trend toward improved average daily gain at days 11–12 in Tri-Solfen^®-treated animals. These data are considered to support the safety of topical anaesthesia, as formulated in Tri-Solfen^®, to the thermocautery disbudding wound in calves.

Intravenous lidocaine infusion for the treatment of acute pain in the pediatric intensive care unit: case series

Introduction: The use of intravenous lidocaine infusion has increased over the past decade as part of a multimodal approach to analgesia in adults; however, information about its safety and tolerability in the pediatric population is limited. Methods: Acute pain management using lidocaine infusion in eleven patients treated in the pediatric intensive care unit. Results: Five cases of postoperative abdominal pain and six cases of non-operative abdominal pain. Two cases were cancer patients affected by neutropenic colitis. Analgesic control achieved was good. Conclusion: Lidocaine infusions are apparently a safe option for the management of acute pain, either post-operative or not, in the pediatric population.

Use of lidocaine with phenylephrine (Co-phenylcaine) spray for anaesthesia of the external auditory canal

OBJECTIVE

A method is described for topical local anaesthesia of the tympanic membrane and ear canal using lidocaine and phenylephrine (Co-phenylcaine) spray and soaked micropatties.

DISCUSSION

The advantages of this method are discussed in comparison to existing methods.

Effects of vasopressin on anesthetic response time and circulatory dynamics of lidocaine

This study aimed to investigate the hypothesis that vasopressin extends the anesthetic response time of lidocaine and does not affect the circulatory dynamics. Rats were sedated with isoflurane; subsequently, breathing was maintained through mechanical ventilation. We infiltrated the first molar area of the upper left jaw with saline (NS, test solution), 2% lidocaine (L), 0.025 IU vasopressin-supplemented 2% lidocaine, 0.05 IU vasopressin-supplemented 2% lidocaine, 0.1 IU vasopressin-supplemented 2% lidocaine, and 0.2 IU vasopressin-supplemented 2% lidocaine (VL₄). Further, anesthetic response times were measured up to 30 min using electric pulp testing methods (n = 4). The anesthetic response times of NS, L, and VL₄ were measured up to 45 min with the aforementioned results as reference values (n = 7). The circulatory dynamics of NS, L, VL₄, and 0.2 IU vasopressin (V) were measured up to 45 min using a non-invasive blood pressure measuring device. VL₄ extended the anesthetic response times of lidocaine compared to L (p < 0.05). Further, V and VL₄ significantly increased the systolic and diastolic blood pressure and significantly decreased the pulse rate (p < 0.05). VL₄ is not a suitable addition to the local anesthetic solution used in dentistry. Further study is needed to determine vasopressin concentration that extends the anesthetic effect without affecting the circulatory dynamics.

Potential Impact of Local Anesthetics Inducing Granulocyte Arrest and Altering Immune Functions on Perioperative Outcome

Introduction

Local anesthetics (LAs) are frequently used during anesthesia; however, they may influence granulocyte function which in turn could modify immune responses in the perioperative period. Therefore, the aim of this study was to investigate the impact of clinically used doses of bupivacaine and lidocaine on granulocyte function with regard to migration, reactive oxygen species (ROS) production, neutrophil extracellular traps (NETosis) formation, and viability.

Methods

A total of 38 granulocyte-enriched samples from healthy subjects were obtained by whole blood lysis. Polymorphonuclear neutrophil (PMN) samples were incubated simultaneously with different concentrations of either bupivacaine (0.03–3.16 mmol/L) or lidocaine (0.007–14.21 mmol/L), or without drug (control). Live cell imaging was conducted in order to observe granulocyte chemotaxis, migration, ROS production, and NETosis. Flow cytometry was used to analyze viability and antigen expression.

Results

The track length (TL) of PMNs exposed to bupivacaine concentrations of 0.16 mmol/L and above significantly decreased compared to the control. Low concentrations of lidocaine were associated with slight but significant increases in TL, whereas this changed with concentrations above 1.4 mmol/L, showing a significant decrease in TL. PMN incubated with bupivacaine concentrations of 1.58 mmol/L and above or lidocaine concentrations of at least 3.6 mmol/L showed no migration or chemotaxis at all. Time to onset of maximal ROS production and time for half-maximal NETosis decreased in a dose-dependent manner for both substances. Equipotency in NETosis induction was reached by bupivacaine (1.1 mmol/L) at significantly lower concentrations than lidocaine (7.96 mmol/L). Cell viability and oxidative burst were unaffected by LAs.

Conclusion

Local anesthetics in clinically used doses ameliorate granulocyte defense mechanisms, thus indicating their potentially decisive effect during the perioperative period.