Central nervous system toxicity following topical skin application of lidocaine

Acute Systemic Toxicity Caused by Topical Application of EMLA Cream on a Leg Ulcer: Case Report and Review of Literature

INTRODUCTION

Systemic toxicity of eutectic mixture of local anesthetics (EMLA) cream is rare and is most commonly observed in children, for example, upon extensive application, and rarely occurs in adults with certain dispositions.

CASE REPORT

We report the case of a 71-year-old man who developed methemoglobinemia and systemic intoxication upon topical application of EMLA cream for leg ulcer and stasis dermatitis prior to surgical debridement. Approximately 45 min after application, the patient was found to be in a somnolent state, was unable to articulate, and showed peripheral cyanosis. The blood concentration of methemoglobin (MetHb) was 15.1%, and therefore, a diagnosis of systemic toxicity of EMLA due to methemoglobinemia was established. After removal of the cream, oxygen was applied, and further observation revealed that the patient's condition rapidly improved without any residue. In the following, we also discuss literature related to systemic EMLA intoxication.

CONCLUSION

EMLA cream may cause severe systemic toxicity even in adults under certain conditions, for example, when applied on damaged skin or in extensive amounts.

Anti-Proliferative Effects of Lidocaine as an Autophagy Inducer in Bladder Cancer via Intravesical Instillation: In Vitro and Xenograft Mouse Model Experiments

Lidocaine exerts potential anti-tumor effects on various cancer cell lines, and its intravesical instillation is considered safer than intravenous administration for bladder cancer. However, the mechanisms underlying its anti-tumor effects have not been fully elucidated. Here, we aimed to elucidate the anti-tumor molecular mechanisms of lidocaine in bladder cancer cells and a xenograft model to substantiate the efficacy of its intravesical administration. We investigated the anti-proliferative and autophagyinducing activities of lidocaine in Nara Bladder Tumor No. 2 (NBT-II) rat bladder carcinoma cells using cell viability, flow cytometry, a wound healing assay, and western blotting. We also established a xenograft mouse model of bladder cancer, and cancer growth was examined using in vivo bioluminescence imaging. Lidocaine decreased cell viability, induced G0/G1 phase cell cycle arrest, and inhibited cell migration partially via glycogen synthase kinase (GSK) 3β phosphorylation. Moreover, a combination of lidocaine and SB216763 (a GSK3β inhibitor) suppressed autophagy-related protein expression. Bafilomycin-A1 with lidocaine significantly enhanced microtubule-associated protein 1A/1B-light chain (LC3B) expression; however, it decreased LC3B expression in combination with 3-methyladenine compared to lidocaine alone. In the xenograft mouse model, the bladder cancer volume was reduced by lidocaine. Overall, lidocaine exerts anti-proliferative effects on bladder cancer via an autophagy-inducing mechanism.

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.

Biodegradable ring-shaped implantable device for intravesical therapy of bladder disorders

Intravesical instillation is an efficient drug delivery route for the local treatment of various urological conditions. Nevertheless, intravesical instillation is associated with several challenges, including pain, urological infection, and frequent clinic visits for catheterization; these difficulties support the need for a simple and easy intravesical drug delivery platform. Here, we propose a novel biodegradable intravesical device capable of long-term, local drug delivery without a retrieval procedure. The intravesical device is composed of drug encapsulating biodegradable polycaprolactone (PCL) microcapsules and connected by a bioabsorbable Polydioxanone (PDS) suture with NdFeB magnets in the end. The device is easily inserted into the bladder and forms a 'ring' shape optimized for maximal mechanical stability as informed by finite element analysis. In this study, inserted devices were retained in a swine model for 4 weeks. Using this device, we evaluated the system's capacity for delivery of lidocaine and resiquimod and demonstrated prolonged drug release. Moreover, a cost-effectiveness analysis supports device implementation compared to the standard of care. Our data support that this device can be a versatile drug delivery platform for urologic medications.

Lidocaine Infusion: An Antiarrhythmic With Neurologic Toxicities

As a renowned local anesthetic agent of choice, lidocaine is also a class 1b antiarrhythmic agent that is primarily used for the treatment of ventricular arrhythmias. Although lidocaine systemic toxicity is rare, it may be life-threatening; thus, its early identification and management are of vital importance. This case report details the clinical scenario of intravenous lidocaine administration to a patient at high risk of toxicity in a 64-year-old patient, who initially presented with sustained monomorphic ventricular tachycardia received lidocaine and subsequently developed neurologic manifestations of lidocaine toxicity, including altered mental status and seizure. The patient was treated promptly with benzodiazepine and discontinuation of lidocaine as the offending agent, with complete resolution of adverse effects.

Lidocaine: A Local Anesthetic, Its Adverse Effects and Management

The most widely used medications in dentistry are local anesthetics (LA), especially lidocaine, and the number of recorded adverse allergic responses, particularly of hazardous responses, is quite low. However, allergic reactions can range from moderate to life-threatening, requiring rapid diagnosis and treatment. This article serves as a review to provide information on LA, their adverse reactions, causes, and management.

Pharmacology of Peripheral Arterial Disease in the Angio Suite: What Every Interventionalist Should Know

Safe and effective treatment of peripheral arterial disease (PAD) and critical limb ischemia can be routinely performed in the angiography suite. A systematic understanding of the medications commonly used during these procedures is essential. This review discusses the traditional roles of the medications used in PAD procedures, the existing evidence basis for those roles, potential alternatives, and evolving techniques. Developing a familiarity with these medications can help improve outcomes and safety for the patients being treated.

Using Single-Cell Amperometry and Intracellular Vesicle Impact Electrochemical Cytometry To Shed Light on the Biphasic Effects of Lidocaine on Exocytosis

Single cell amperometry and intracellular vesicle impact electrochemical cytometry were used to examine whether lidocaine can regulate neurotransmitter release or storage for PC12 cells to explain the biphasic effects whereby it can protect neurons and improve cognitive outcome at low concentration, but can cause neurotoxicity at high concentration. We show that lidocaine affects the behavior of PC12 cell exocytosis in a concentration dependent way, which exactly corresponds to its biphasic effects. At a relatively high concentration, it shows a much narrower pore size and a longer-duration fusion pore with less monoamine released than control cells. However, at a relatively low concentration, the fusion pore is open even longer than at high concentration, and with more monoamine released than control cells. Furthermore, intracellular vesicle impact electrochemical cytometry was used to confirm that lidocaine did not change the catecholamine content of the vesicles. These data provide a mechanism for the observed biphasic effects of the drug and suggest that lidocaine influences exocytosis through multiple mechanisms.

Lidocaine-Induced Systemic Toxicity: A Case Report and Review of Literature

For the past 50 years, local anesthetics such as lidocaine have been commonly used in various clinical settings. Its use is not just limited to anesthesia and surgery but is also frequently utilized in internal medicine and in primary care setting for bedside procedures. Despite its widespread use, most physicians are not familiar with the life-threatening manifestations of lidocaine toxicity and its treatment. Our case demonstrates a successful resuscitation after cardiac arrest in a healthy 33-year-old female with systemic lidocaine toxicity after she received lidocaine as a local anesthetic. Our goal is to educate general internists and primary care physicians of the possible hazards of lidocaine use. We also aim to create mindfulness of the symptoms of lidocaine toxicity and the use of intravenous lipid emulsion as an antidote.

Recurrent seizures after lidocaine ingestion

Lidocaine has a concentration-dependent effect on seizures. Concentrations above 15 μg/mL frequently result in seizures in laboratory animals and human. We report a case of central nervous system (CNS) lidocaine toxicity and recurrent seizure after erroneous ingestion of lidocaine solution. A 4-year-old boy presented to the Emergency Department of Imam Hospital of Sari in December 2013 due to tonic-clonic generalized seizures approximately 30 min ago. 3 h before seizure, his mother gave him 2 spoons (amount 20-25 cc) lidocaine hydrochloride 2% solution instead of pediatric gripe by mistake. Seizure with generalized tonic-clonic occurred 3 times in home. Neurological examination was essentially unremarkable except for the depressed level of consciousness. Personal and medical history was unremarkable. There was no evidence of intracranial ischemic or hemorrhagic lesions in computed tomography scan. There were no further seizures, the condition of the patient remained stable, and he was discharged 2 days after admission. The use of viscous lidocaine may result in cardiovascular and CNS toxicity, particularly in children. Conservative management is the best option for treatment of lidocaine induced seizure.

Neurologic toxicity of lidocaine during awake intubation in a patient with tongue base abscess. Case report

Lidocaine is commonly used for topical anesthesia of the upper airway in patient with anticipated difficult tracheal intubation undergoing awake fiberoptic intubation. Lidocaine toxicity is dose related and proportional to its plasma level. Although neurologic toxicity has been frequently observed with intravenous use, it has also been reported for topical use. We report on a case of a patient with base tongue abscess who developed sudden seizures and coma during application of topical anesthesia with lidocaine for awake fiberoptic intubation. The presence of a deep neck infection that causes hyperemia and edema of the pharyngolaryngeal mucosa may enhance transmucosal systemic absorption of local anesthetic. Moreover, conditions such as hypercarbia, dysphagia, or hepatic diseases are known to facilitate onset of lidocaine neurologic toxicity with serum concentration lower than normal. These findings should be kept in mind before administering topical anesthesia of the upper airway. In the presence of any of these conditions above, either the total dose of local anesthetic or its concentration should be reduced as much as possible.

Topical lidocaine enhanced by laser pretreatment: a safe and effective method of analgesia for facial rejuvenation

BACKGROUND

Injectable forms of anesthesia for nonsurgical facial rejuvenation, although efficacious, are uncomfortable for the patient. Preclinical studies have demonstrated that laser pretreatment at low energies enhances absorption of topical lidocaine.

OBJECTIVES

The authors assess the safety and efficacy of laser-assisted transdermal delivery of topical anesthetic.

METHOD

Ten patients were split into 2 groups (A and B). All patients received 15 g of BLT (20% benzocaine, 6% lidocaine, and 4% tetracaine triple anesthetic cream) for 20 minutes with no occlusion. Then the cream was removed and the first blood draw taken. Group A patients were pretreated with the full ablative laser and group B patients with a fractional ablative laser to the full face. A further 15 g BLT was applied for another 20 minutes. Group A patients then underwent full ablative laser treatment, and group B received fractionated ablative laser treatment. Blood draws were taken at 60, 90, 120, 180, and 240 minutes after the initial topical anesthetic application, and the serum was analyzed for lidocaine and monoethylglycinexylidide (MEGX) levels. Patients were asked to rate the pain felt at intervals during the procedure.

RESULTS

No patient required supplemental nerve blocks. Pain scores were equivalent at the end of the first pass for both groups (P = .436). Group A patients had significantly lower pain scores at the start of the second laser treatment (P = .045), but pain scores became equivalent by the end (P = .323). Combined serum lidocaine and MEGX levels were significantly higher in group A patients up to 90 minutes (peak average of 0.61 µg/mL for group A and 0.533 µg/mL for group B; P = .0253), which corresponded to greater initial analgesic effect.

CONCLUSIONS

Data from this study demonstrate that topical anesthetic for facial rejuvenation can be enhanced with laser pretreatment while maintaining safe blood serum levels. Further studies should examine optimal application amount and time to allow safe multipass facial rejuvenation without the need for invasive nerve blocks.

Autonomic dysreflexia with negative-pressure wound therapy: a report of two cases

Pressure ulcers and autonomic dysreflexia (AD) are common complications that may affect individuals with spinal cord injury (SCI). Negative-pressure wound therapy (NPWT) is a frequently used modality to aid in wound healing in the treatment of pressures ulcers in patients with SCI. Although the common triggers of AD have been well described in the literature, there have been no formal reports of NPWT itself as a cause of AD. We detail 2 cases of patients with SCI and with AD thought to be secondary to NPWT and discuss modifications made to allow for continued treatment with NPWT while minimizing further episodes of AD. We propose that NPWT should be considered as a potential source of AD in patients with SCI undergoing this therapy.

Toxicity of topical lidocaine applied to the breasts to reduce discomfort during screening mammography

BACKGROUND

We measured the effect of 30 milliliters (mL) of 4% lidocaine gel on the breasts and chest wall of healthy women covered for 1 h on plasma concentrations of lidocaine and its principal metabolite, monoethylglycinexylidide (MEGX), electrocardiogram (EKG) results, and adverse events.

MATERIALS AND METHODS

This institutional review board-approved, prospective, open-label study complied with the Health Insurance Portability and Accountability Act (HIPAA). The study evaluated 10 healthy women aged 42-75 years with 30 mL of 4% lidocaine gel on the skin of the breasts and chest wall covered for 1 h. Cardiac and neurological assessments were performed and blood was drawn for lidocaine and MEGX levels at baseline and 1/2, 1, 2, 3, 4, 6, and 8 h after application. EKGs were performed before application and at 3 h. Subjects provided informed written consent. Primary and secondary outcomes were plasma concentrations of lidocaine and MEGX and frequency of adverse events, respectively. Statistical analysis included paired t-tests for EKGs and repeated measures regression for vital signs.

RESULTS

No lidocaine was detected in the blood of 9 of 10 subjects. One subject had low plasma concentrations of lidocaine just above the level of detection the first 4 h after application only. No MEGX was detected. Mean decrease in heart rate was likely multifactorial.

CONCLUSION

Thirty mL of 4% lidocaine gel on the breasts and chest wall covered for 1 h in healthy women resulted in plasma concentrations of lidocaine and MEGX well below therapeutic or toxic levels and no clinically significant adverse events.

Anesthesia methods in laser resurfacing

Laser resurfacing technology offers the ability to treat skin changes that are the result of the aging process. One of the major drawbacks of laser resurfacing technologies is the pain associated with the procedure. The methods of anesthesia used in laser resurfacing to help minimize the pain include both noninvasive and invasive procedures. The noninvasive procedures can be divided into topical, cryoanesthesia, and a combination of both. The invasive methods of anesthesia include injected forms (infiltrative, nerve blocks, and tumescent anesthesia) and supervised anesthesia (monitored anesthesia care and general anesthesia). In this review, the authors summarize the types of anesthesia used in laser resurfacing to aid the provider in offering the most appropriate method for the patient to have as painless a procedure as possible.

Effect of 4% topical lidocaine applied to the face on the serum levels of lidocaine and its metabolite, monoethylglycinexylidide

BACKGROUND

Topical lidocaine is a common form of anesthesia for a wealth of procedures across a large number of disciplines, including laser treatments. Preparations can be purchased over the counter with no prescription necessary. It is considered a safer and more acceptable form of anesthetic than hypodermic injections; however, there have been reports of fatalities following its application. Above certain serum lidocaine concentrations, patients may experience effects of toxicity such as lightheadedness and paraesthesia; these effects can progress to seizures and cardiorespiratory depression, which can ultimately lead to death. The active metabolite of lidocaine, monoethylglycinexylidide (MEGX), can be almost as potent as lidocaine in terms of toxicity.

OBJECTIVES

The authors examine the levels of both lidocaine and MEGX in blood serum after application of topical lidocaine.

METHODS

Twenty-five healthy volunteers were assigned to one of four groups (A, B, C, D). Group A had 2.5 g of 4% lidocaine topical anesthetic cream applied to the face for one hour without occlusion, Group B had 5 g applied to the face for one half-hour without occlusion, Group C had 5 g applied to the face for one hour without occlusion, and Group D had 5 g applied to the face for one hour with occlusion. To evaluate serum concentrations, blood was drawn every 30 minutes for four hours.

RESULTS

Group D showed the highest serum levels of lidocaine and MEGX, a three-fold increase compared with group C, which received the same dose (5g topical 4% lidocaine) but without occlusion. In group D, peak serum levels occurred at 90 minutes for serum lidocaine, which was also the fastest of the four groups. Serum MEGX levels peaked much later than serum lidocaine levels, at 210 minutes. Individual serum levels did not exceed 0.6 µg/mL. Across the groups, there was significant interindividual variation in both lidocaine and MEGX serum levels (P = .061). Applications of 5 g of 4% lidocaine resulted in higher serum concentration of both lidocaine and MEGX. When comparing group A to group C, doubling the dose of 4% lidocaine from 2.5 g to 5 g resulted in double the serum levels of MEGX and a 50% increase in the serum lidocaine levels (P = .021). When comparing groups C and D, the addition of an occlusive dressing resulted in a tripling of the serum lidocaine levels and a doubling of the serum MEGX levels, both of which were statistically significant (P < .001). When comparing all four groups, there were significant differences between the combined serum concentrations of lidocaine and MEGX (P < .001).

CONCLUSIONS

Topical lidocaine preparations are increasingly being employed to provide a patient-friendly form of noninvasive analgesia for a multitude of procedures. Some preparations are available over the counter for unsupervised patient application. Our study has demonstrated significant interindividual variability for a given dose, especially when occlusion is applied. There have been fatalities resulting from topical lidocaine application, and our study suggests that this is the result of the unpredictability of lidocaine metabolism between individuals. Therefore, we recommend that caution be exercised with topical lidocaine preparations, in particular when applied in conjunction with occlusive dressings.

Effect of PaCO2 and PaO2 on lidocaine and articaine toxicity

Alterations in arterial PaCO₂ can influence local anesthetic toxicity. The objective of this study was to evaluate the effect of stress-induced changes in PaCO₂ and PaO₂ on the seizure threshold of lidocaine and articaine. Lidocaine (2% with 1 : 100,000 epinephrine) or articaine (4% with 1 : 100,000 epinephrine) was administered intravenously under rest or stress conditions to 36 rats separated into 4 groups. Propranolol and prazosin were administered preoperatively to minimize cardiovascular effects of epinephrine. Mean arterial pressure (MAP), heart rate (HR), and arterial pH, PaCO₂, and PaO₂ were measured. Results showed no differences in MAP, HR, or pH. Stress significantly increased the latency period for the first tonic-clonic seizure induced by a toxic dose of both lidocaine and articaine (P < .05). Seizures were brought on more rapidly by articaine. No significant difference between toxic doses of lidocaine and articaine was noted. Stress raised the seizure threshold dose for both drugs and significantly (P < .01) increased arterial PaO₂ from 94.0 ± 1.90 mm Hg to 113.0 ± 2.20 mm Hg, and reduced PaCO₂ from 36.0 ± 0.77 mm Hg to 27.0 ± 0.98 mm Hg. In conclusion, reduction in PaCO₂ and/or increase in PaO₂ raised the seizure threshold of lidocaine and articaine. This study also confirmed that lidocaine and articaine have equipotent central nervous system toxicity.

[Methemoglobin intoxication by prilocaine in EMLA. Accidental intoxication of an infant with scald injuries]

The case of an infant who had received EMLA(R) for local pain therapy after scalding to 5% of the body surface with boiling water is reported. Due to the application of EMLA(R) on the injured skin and exceeding the recommended doses of prilocaine and lidocaine the child developed symptomatic methemoglobinemia. During surgical wound dressing the boy showed cyanosis, decreased peripheral oxygen saturation and potentially suffered a general seizure. With a symptomatic therapy including mechanical ventilation and anticonvulsive drugs the methemoglobinemia normalized within 9 h. The child recovered without any neurological impairment after wound treatment was completed.

Local anaesthetics for acute reversible blockade of the sympathetic baroreceptor reflex in the rat

Sinoaortic denervation is a common method used in the investigation of function in the cardiovascular system. In the rat, this is usually accomplished by transection of the carotid sinus and aortic depressor nerves, which is permanent. We propose a novel, and simple method for acute baroreceptor denervation in the rat in which the region around the carotid sinuses is superfused with local anaesthetic agents. We demonstrate that complete baroreceptor denervation can be achieved for longer (bupivacaine, 30-60 min) or shorter (lignocaine, 10-30 min) periods, without harming the physiological state of the rat.