Comparison of the efficacy and safety of 2% lidocaine HCl with different epinephrine concentration for local anesthesia in participants undergoing surgical extraction of impacted mandibular third molars: A multicenter, randomized, double-blind, crossover, phase IV trial

Physiology of pregnancy and oral local anesthesia considerations

Background

Safe and effective local anesthesia is a prerequisite for emergency oral surgeries and most dental treatments. Pregnancy is characterized by complex physiological changes, and increased sensitivity to pain. Pregnant women are particularly vulnerable to oral diseases, such as caries, gingivitis, pyogenic granuloma and third molar pericoronitis. Maternally administered drugs can affect the fetus through the placenta. Therefore, many physicians and patients are reluctant to provide or accept necessary local anesthesia, which leads to delays in the condition and adverse consequences. This review is intended to comprehensively discuss the instructions for local anesthesia in the oral treatment of pregnant patients.

Methodology

An in-depth search on Medline, Embase, and the Cochrane Library was performed to review articles concerned with maternal and fetal physiology, local anesthetic pharmacology, and their applications for oral treatment.

Results

Standard oral local anesthesia is safe throughout the pregnancy. At present, 2% lidocaine with 1:200,000 epinephrine is considered to be the anesthetic agent that best balances safety and efficacy for pregnant women. Maternal and fetal considerations must be taken into account to accommodate the physiological and pharmacological changes in the gestation period. Semi-supine position, blood pressure monitoring, and reassurance are suggested for high-risk mothers to reduce the risk of transient changes in blood pressure, hypoxemia, and hypoglycemia. For patients with underlying diseases, such as eclampsia, hypertension, hypotension, and gestational diabetes, the physicians should use epinephrine cautiously and control the dose of anesthetic. New local anesthesia formulations and equipment, which contribute to minimizing injection pain and relieving the anxiety, have and are being developed but remain understudied.

Conclusions

Understanding the physiological and pharmacological changes during pregnancy is essential to ensure the safety and efficiency of local anesthesia. Optimal outcomes for the mother and fetus hinge on a robust understanding of the physiologic alterations and the appropriate selection of anesthetic drugs and approaches.

Human Bone Marrow Mesenchymal Stem Cells-Derived Exosomal miRNA-21-5p Inhibits Lidocaine-Induced Apoptosis in SH-SY5Y Neuroblastoma Cells

Background

Local anesthetic lidocaine is one of the most common pain therapies, but high concentration of lidocaine induced neurotoxicity and its mechanism is unclear. Exosomal microRNAs (miRNAs) is implicated in neuronal diseases, but its role in lidocaine induced neurotoxicity remains to be elucidated.

Methods

All the experiments were performed at Huzhou Key Laboratory of Molecular Medicine, Huzhou City, Jiangsu Province, China in 2022. Lidocaine was used to induce apoptosis of SH-SY5Y cells. Exosomes isolated from bone marrow mesenchymal stem cells (BMSC-exos) were used to co-treat SH-SY5Y cells with lidocaine. Cell apoptosis was measured using a flow cytometer. PKH-67 Dye was used for exosome uptake assay. miR-21-5p mimics/inhibitors, or negative controls were transfected with Lipo2000 to study its effect on lid-induced injury. Interactions between miR-21-5p and PDCD4 was analyzed by luciferase reporter assay.

Results

Administration of BMSC-exo protected SH-SY5Y cells against lidocaine induced apoptosis. Suppressing miR-21-5p dramatically enhanced PDCD4, but miR-21-5p overexpression sharply down-regulated PDCD4. Mechanism study showed that miR-21-5p bound to 3'-UTR of PDCD4 to inhibit it. Suppressing miR-21-5p reversed the effect of BMSC-exo on Lid-induced injury. Results also indicate that miR-21-5p regulated lidocaine-induced injury through targeting PDCD4.

Conclusion

BMSC-exos protected SH-SY5Y cells against lidocaine induced apoptosis through miR-21-5p by targeting PDCD4, which may develop new strategy in the management of lidocaine-induced neurotoxicity.

Safety and efficacy of lidocaine plus epinephrine on intraoperative bleeding in abdominal myomectomy: A double-blind clinical trial

Background

Uterine fibroid is a common benign pelvic tumor and abdominal myomectomy may cause excessive intraoperative bleeding, which may lead to adverse outcomes.

Objective

This study was planned to evaluate the effectiveness of the injection of lidocaine plus epinephrine to reduce intraoperative bleeding in abdominal myomectomy.

Methods

During October 2019 and May 2020, 60 eligible women with uterine fibroids were enrolled in a randomized controlled trial. Our patients were divided into two groups of lidocaine plus epinephrine defined as Group L and placebo defined as Group P. In group L, lidocaine 3 mg/kg plus 0.5 ml of adrenaline which reached to 50 cc with saline solution and in group P, 50 ml of normal saline was used. Both the combined solution and normal saline were infiltrated to the serous and myometrium above and around the fibroid before incision. Patients' demographic data, total operative time, hemoglobin changes, and the degree of surgical difficulty were evaluated and compared between the two groups.

Results

There was no significant difference between the two groups in terms of demographic data. Hemoglobin changes (p <  0.0001) and the degree of surgery difficulty (p = 0.01) were significantly lower in Group L compared with Group P. In each group the drop in hemoglobin levels from baseline to 4 h postoperatively was significant (p <  0.0001). A significantly meaningful correlation was reported between hemoglobin changes and the degree of surgery difficulty with the size of the uterine and fibroids (p < 0.05). While a negative correlation was found regarding gravidity and surgery difficulty (r = -0.413, p = 0.02). Surgery duration was longer in Group P compared with Group L 70.66 ± 19.85 versus 66.16 ± 14.48, respectively, but with no significant difference (p = 0.32). No significant adverse reaction or serious complication was reported in the two groups. Hemodynamic parameters were kept in the normal range throughout the surgery.

Conclusion

A combination of lidocaine plus epinephrine during abdominal myomectomy appears to be a safe and effective method in reducing blood loss.

Effectiveness of anesthetic solutions for pain control in lower third molar extraction surgeries: a systematic review of randomized clinical trials with network meta-analysis

OBJECTIVE

To assess the effectiveness of different anesthetic solutions for pain control immediately after the extraction of lower third molars.

METHODS

Nine databases were used to identify randomized clinical trials, without restriction of language or year of publication. The "JBI Critical Appraisal Tools for Systematic Reviews" was used to assess the risk of bias in the studies. The network meta-analysis was performed to compare the effectiveness of different anesthetics to control the pain immediately after the surgery of lower third molars, using the standardized mean difference (SMD) as the effect estimate. The GRADE approach was used to assess the certainty of evidence.

RESULTS

The search presented 13,739 initial results, from which 45 met the eligibility criteria and presented low to moderate risk of bias. Thirteen studies were included in the meta-analysis. The 2% lidocaine + clonidine presented the lowest pain scores (SMD = - 1.44; - 2.72 to - 0.16) compared to 4% articaine + adrenaline, followed by 0.5% bupivacaine + adrenaline (SMD = - 1.36; - 2.13 to - 0.59). The certainty of evidence varied between very low to moderate.

CONCLUSION

2% lidocaine + clonidine and 0.5% bupivacaine + adrenaline were the anesthetics with the highest probability for pain control immediately after the surgical procedure of removing impacted lower third molars.

CLINICAL SIGNIFICANCE

The use of an adequate anesthetic with effective pain control can contribute to a more comfortable postoperative period.

Volume and effectiveness assessment of articain 4% versus mepivacaine 2% used in third molar surgery: randomized, double-blind, split-mouth controlled clinical trial

Background

The different indications for extraction of the lower third molars, require resources to manage pain and discomfort, such as, for example, adequate anesthetic techniques, and the type of anesthetic used can influence the management of pain in tooth extractions. Few studies in the literature compare the anesthetics 4% articaine hydrochloride and 2% mepivacaine hydrochloride showing evidence that both allow for successful pain management. This study sought to compare the volume, efficacy and safety of these two anesthetic drugs, both associated with epinephrine at a ratio of 1:100,000, used in the extraction of lower third molars.

Material and Methods

A controlled, clinical, split-mouth compared these both local anesthetics in a sample of 20 patients requiring bilateral extraction of teeth. Pain was the main parameter to be assessed by means of the visual analogue scale (VAS) applied during and immediately after the surgery. Hemodynamic parameters, adverse events, presence of paresthesia and satisfaction of patients and surgeon were also analysed.

Results

Pain management was more effective with mepivacaine up to two hours after surgery (p=0.014), whereas the surgeon was more satisfied with the use of articaine during divulsion and suture (p<0.05). However no statistically significant differences were found between both anesthetics regarding pain perception.

Conclusions

It was observed that both anesthetics are efficient and safe in the management of pain for extraction of third molars, in which less amount of mepivacaine is needed. The satisfaction of patients and surgeon was the same for both anesthetics, with articaine being highlighted during divulsion and suture.

Key words:Pain, third molar, local anaesthesia, paresthesia.

[Experimental study of the effectiveness of local anesthetic activity of a new dimethylphenylacetamide-containing pharmaceutical composition in chronic periodontitis]

Novel anaesthetic formulation LHT-15-32 was studied. The experimental study involved 66 white mice, 15 Rana radibunda frogs and 50 male Sprague Dawley rats. Its acute intravenous and subcutaneous toxicity was determined in mice. Pain sensitivity threshold of upper second molar was determined in rats with experimental periodontitis. Oxidative stress activity and total antioxidant capacity were determined in rats' gingival mucosa by induced chemiluminescence. Tissue IL-1β, IL-10 and TNF-a concentration was quantitatively assessed by ELISA. LHT-15-32 Na-blocking activity was studied on isolated neurons of Limnea stagnalis para-pharyngeal ganglion. Rana radibunda isolated sciatic nerve was perfused with LHT-15-32 to assess its conductivity. LHT-15-32 acute intravenous and subcutaneous toxicity was lower then that of its active substance LHT-4-00. The formulation infraorbital administration induced deep dental anaesthesia lasted longer than 70 min, activated local antioxidant defence system and decreased IL-1β level in gingival tissue. At 10^-6 to 10^-3 M LHT-15-32 inhibited sciatic nerve conductivity and blocked Na⁺-channels of isolated neurons in dose-dependent manner. LHT-15-32 proved to be less toxic than active substance and lidocaine. The agent provides deep and prolonged anesthesia of the upper molar of rats in chronic apical periodontitis, lowers tissue concentration of pain cascade cytokines and oxidative stress activity and suppresses the action potential amplitude of a sensory nerve due to Na-blocking activity.

Novel Dimethylacetamide-Containing Formulation Improves Infraorbital Anaesthesia Efficacy in Rats with Periodontitis

Background

To evaluate acute toxicity and local anaesthetic activity of a formulation containing a novel dimethylacetamide derivative, antioxidant, and vasoconstrictor in rats with chronic periodontitis.

Methods

Novel anaesthetic dimethylacetamide-containing formulation LHT-15-32 was studied as 2% water solution. Its acute intravenous and subcutaneous toxicity was determined in mice. Pain sensitivity threshold of the upper second molar was determined in rats with experimental periodontitis. Oxidative stress activity and total antioxidant capacity were determined in rats' gingival mucosa by induced chemiluminescence. Local changes were evaluated in periodontal tissue by morphological examination. Tissue IL-1β, IL-10, and TNF-α concentration was quantitatively assessed by an enzyme-linked immunosorbent assay. LHT-15-31 Na-blocking activity was studied on isolated neurons of Limnaea stagnalis' parapharyngeal ganglion. Isolated sciatic nerve of Rana radibunda was perfused with different concentrations of LHT-15-32 to assess its conductivity. Statistical analysis was used, and continuous variables were presented as mean ± square deviation. The normality of distribution was determined using ANOVA. Newman–Keuls parametric criterion was used for intergroup comparison. LD₅₀ indexes were calculated by probit analysis.

Results

LHT-15-32 acute intravenous and subcutaneous toxicity was lower than that of its active substance. The formulation by infraorbital administration induced deep dental anaesthesia which lasted over 70 min and activated the local antioxidant defense system and decreased IL-1β level in gingival tissue. LHT-15-32 triggered tissue reparation around the impacted upper molar in rats assessed five days after administration. At 10⁻⁶ to 10⁻³ M concentration, LHT-15-32 inhibited sciatic nerve conductivity and blocked Na⁺ channels of isolated neurons in a dose-dependent manner.

Conclusions

The formulation may be considered as an effective and safe approach to anaesthetize upper molars with periodontitis.

Dopamine enhancement of dextrorphan-induced skin antinociception in response to needle pinpricks in rats

BACKGROUND

Dextrorphan with long-acting local anesthetic effects did not cause system toxicity as fast as bupivacaine, while catecholamines (i.e., epinephrine) with the vasoconstrictive characteristics enhanced the effects of local anesthetic drugs. The objective of the experiment was to examine the synergistic effect of local dopamine (a catecholamine) injection on cutaneous antinociception of dextrorphan.

METHODS

The panniculus reflex in response to skin stimulation with a needle was used as the primary endpoint when dextrorphan (1.50, 2.61, 5.46, 10.20 and 20.40 μmol) alone, dopamine (16.20, 32.40, 51.60, 60.00 and 81.60 μmol) alone, or dopamine + dextrorphan (a ratio of ED₅₀vs. ED₅₀) was injected subcutaneously on the rat's back. We used an isobolographic modelling approach to determine whether a synergistic effect would be observed.

RESULTS

We showed that dextrorphan, dopamine, or the mixture of dopamine and dextrorphan produced dose-related skin antinociception. The potency (ED₅₀, 50% effective dose) for cutaneous antinociception was dextrorphan [6.02 (5.93-6.14) μmol] greater than dopamine [48.91 (48.80-49.06) μmol] (p < 0.01). The duration of nociceptive inhibition induced by dopamine was longer than that induced by dextrorphan (p <  0.01) based on their equipotent doses (ED₂₅, ED₅₀, and ED₇₅). Enhancement and prolongation of skin antinociception occurred after co-administration of dopamine with dextrorphan.

CONCLUSIONS

When compared to dopamine, dextrorphan was more potent and had a shorter duration of skin nociceptive block. Dopamine produced a synergistic effect on dextrorphan-mediated antinociception, and prolonged dextrorphan's antinociceptive duration.

Injectable local anaesthetic agents for dental anaesthesia

BACKGROUND

Pain during dental treatment, which is a common fear of patients, can be controlled successfully by local anaesthetic. Several different local anaesthetic formulations and techniques are available to dentists.

OBJECTIVES

Our primary objectives were to compare the success of anaesthesia, the speed of onset and duration of anaesthesia, and systemic and local adverse effects amongst different local anaesthetic formulations for dental anaesthesia. We define success of anaesthesia as absence of pain during a dental procedure, or a negative response to electric pulp testing or other simulated scenario tests. We define dental anaesthesia as anaesthesia given at the time of any dental intervention.Our secondary objective was to report on patients' experience of the procedures carried out.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; the Cochrane Library; 2018, Issue 1), MEDLINE (OVID SP), Embase, CINAHL PLUS, WEB OF SCIENCE, and other resources up to 31 January 2018. Other resources included trial registries, handsearched journals, conference proceedings, bibliographies/reference lists, and unpublished research.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) testing different formulations of local anaesthetic used for clinical procedures or simulated scenarios. Studies could apply a parallel or cross-over design.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodological approaches for data collection and analysis.

MAIN RESULTS

We included 123 studies (19,223 participants) in the review. We pooled data from 68 studies (6615 participants) for meta-analysis, yielding 23 comparisons of local anaesthetic and 57 outcomes with 14 different formulations. Only 10 outcomes from eight comparisons involved clinical testing.We assessed the included studies as having low risk of bias in most domains. Seventy-three studies had at least one domain with unclear risk of bias. Fifteen studies had at least one domain with high risk of bias due to inadequate sequence generation, allocation concealment, masking of local anaesthetic cartridges for administrators or outcome assessors, or participant dropout or exclusion.We reported results for the eight most important comparisons.Success of anaesthesiaWhen the success of anaesthesia in posterior teeth with irreversible pulpitis requiring root canal treatment is tested, 4% articaine, 1:100,000 epinephrine, may be superior to 2% lidocaine, 1:100,000 epinephrine (31% with 2% lidocaine vs 49% with 4% articaine; risk ratio (RR) 1.60, 95% confidence interval (CI) 1.10 to 2.32; 4 parallel studies; 203 participants; low-quality evidence).When the success of anaesthesia for teeth/dental tissues requiring surgical procedures and surgical procedures/periodontal treatment, respectively, was tested, 3% prilocaine, 0.03 IU felypressin (66% with 3% prilocaine vs 76% with 2% lidocaine; RR 0.86, 95% CI 0.79 to 0.95; 2 parallel studies; 907 participants; moderate-quality evidence), and 4% prilocaine plain (71% with 4% prilocaine vs 83% with 2% lidocaine; RR 0.86, 95% CI 0.75 to 0.99; 2 parallel studies; 228 participants; low-quality evidence) were inferior to 2% lidocaine, 1:100,000 epinephrine.Comparative effects of 4% articaine, 1:100,000 epinephrine and 4% articaine, 1:200,000 epinephrine on success of anaesthesia for teeth/dental tissues requiring surgical procedures are uncertain (RR 0.85, 95% CI 0.71 to 1.02; 3 parallel studies; 930 participants; very low-quality evidence).Comparative effects of 0.5% bupivacaine, 1:200,000 epinephrine and both 4% articaine, 1:200,000 epinephrine (odds ratio (OR) 0.87, 95% CI 0.27 to 2.83; 2 cross-over studies; 37 participants; low-quality evidence) and 2% lidocaine, 1:100,000 epinephrine (OR 0.58, 95% CI 0.07 to 5.12; 2 cross-over studies; 31 participants; low-quality evidence) on success of anaesthesia for teeth requiring extraction are uncertain.Comparative effects of 2% mepivacaine, 1:100,000 epinephrine and both 4% articaine, 1:100,000 epinephrine (OR 3.82, 95% CI 0.61 to 23.82; 1 parallel and 1 cross-over study; 110 participants; low-quality evidence) and 2% lidocaine, 1:100,000 epinephrine (RR 1.16, 95% CI 0.25 to 5.45; 2 parallel studies; 68 participants; low-quality evidence) on success of anaesthesia for teeth requiring extraction and teeth with irreversible pulpitis requiring endodontic access and instrumentation, respectively, are uncertain.For remaining outcomes, assessing success of dental local anaesthesia via meta-analyses was not possible.Onset and duration of anaesthesiaFor comparisons assessing onset and duration, no clinical studies met our outcome definitions.Adverse effects (continuous pain measured on 170-mm Heft-Parker visual analogue scale (VAS))Differences in post-injection pain between 4% articaine, 1:100,000 epinephrine and 2% lidocaine, 1:100,000 epinephrine are small, as measured on a VAS (mean difference (MD) 4.74 mm, 95% CI -1.98 to 11.46 mm; 3 cross-over studies; 314 interventions; moderate-quality evidence). Lidocaine probably resulted in slightly less post-injection pain than articaine (MD 6.41 mm, 95% CI 1.01 to 11.80 mm; 3 cross-over studies; 309 interventions; moderate-quality evidence) on the same VAS.For remaining comparisons assessing local and systemic adverse effects, meta-analyses were not possible. Other adverse effects were rare and minor.Patients' experiencePatients' experience of procedures was not assessed owing to lack of data.

AUTHORS' CONCLUSIONS

For success (absence of pain), low-quality evidence suggests that 4% articaine, 1:100,000 epinephrine was superior to 2% lidocaine, 1:100,000 epinephrine for root treating of posterior teeth with irreversible pulpitis, and 2% lidocaine, 1:100,000 epinephrine was superior to 4% prilocaine plain when surgical procedures/periodontal treatment was provided. Moderate-quality evidence shows that 2% lidocaine, 1:100,000 epinephrine was superior to 3% prilocaine, 0.03 IU felypressin when surgical procedures were performed.Adverse events were rare. Moderate-quality evidence shows no difference in pain on injection when 4% articaine, 1:100,000 epinephrine and 2% lidocaine, 1:100,000 epinephrine were compared, although lidocaine resulted in slightly less pain following injection.Many outcomes tested our primary objectives in simulated scenarios, although clinical alternatives may not be possible.Further studies are needed to increase the strength of the evidence. These studies should be clearly reported, have low risk of bias with adequate sample size, and provide data in a format that will allow meta-analysis. Once assessed, results of the 34 'Studies awaiting classification (full text unavailable)' may alter the conclusions of the review.

Comparative evaluation of the efficacy, safety, and hemostatic effect of 2% lidocaine with various concentrations of epinephrine

BACKGROUND

We evaluated the changes in mean arterial pressure (MAP) and heart rate (HR), and the anesthetic and hemostatic effects, after injection of 2% lidocaine containing various concentrations of epinephrine in rats and mice to determine the appropriate concentration of epinephrine in various anesthetic mixtures.

METHODS

Rats and mice were randomly allocated to experimental groups: 2% lidocaine without epinephrine (L0), 2% lidocaine with epinephrine 1:200,000 (L200), 1:100,000 (L100), and 1:80,000 (L80). Changes in MAP and HR after administration of the anesthetic mixture were evaluated using a physiological recording system in rats. Onset and duration of local anesthesia was evaluated by pricking the hind paw of mice. A spectrophotometric hemoglobin assay was used to quantify the hemostatic effect.

RESULTS

MAP increased in response to epinephrine in a dose-dependent manner; it was significantly higher in the L80 group than in the L0 group at 5 min post-administration. The HR was relatively lower in the L0 group than in the L80 group. The time required for onset of action was < 1 min in all evaluation groups. The duration of action and hemostatic effect of the local anesthetic were significantly better in the L200, L100, and L80 groups than in the L0 group.

CONCLUSION

L200 demonstrated relatively stable MAP and HR values with satisfactory efficacy and hemostatic effect. L200 might be a better local anesthetic for dental patients in terms of anesthetic efficacy and safety.