An evaluation of 10 percent and 20 percent benzocaine gels in patients with acute toothaches: efficacy, tolerability and compliance with label dose administration directions

An overview of local anesthetics in over-the-counter products

Over-the-counter (OTC) local anesthetics have historically been used to alleviate pain in several common conditions including toothache and sore throat. With a rise in chronic conditions and an aging population, there has been an increase in associated chronic pain-related disorders. Individuals with chronic pain often seek OTC treatments for quick and accessible pain relief. There are several common OTC local anesthetics, including benzocaine, lidocaine, and dibucaine, which are readily available to patients in several formulations. In order to appropriately advise patients on the use of local anesthetics, it is important to understand their key characteristics, including the mechanism of action, clinical properties, pharmacokinetics, clinical applications, and adverse reactions, which may occur.

Effectiveness and Tolerability of a New Formulation of a Topical Anesthetic in Reduction of Pain and Parents’ Satisfaction in Pediatric Dentistry

The aim of the present study was to test a new topical anesthetic gel with a different formulation (10% lidocaine, 10% prilocaine) to analyze its effectiveness in pain control, during the subsequent injection of local anesthetic, and the presence of any side effects. Methods: The study’s research design was a randomized controlled clinical trial on 300 children, aged 5–8 years, divided into two groups, each of 150 patients, according to pre-injection procedures (presence or absence of topical anesthesia). The injection pain was analyzed using the Wong-Baker Faces Pain Rating Scale (PRS) and the Face, Legs, Activity, Cry, Consolability Scale (FLACC). At the end of the procedures, patients’ parents’ satisfaction was recorded. The data were analyzed using the Student’s T test, Mann–Whitney U test and Chi-square test. Results: There were statistically significant differences between the two groups both in the PRS and FLACC ratings. Both in subjective and objective pain evaluations, significantly higher pain ratings were observed in the group without topical anesthesia. There was also a statistically significant difference in terms of patients’ parents’ judgment, as in the group with the use of topical anesthetic the level of parental satisfaction is statistically higher. Conclusion: The experimental anesthetic has proved very effective in its use as a topical gel in both pain measurement scales, thus validating its use on the oral mucosa, for its pharmacological and psychological effect, in the total absence of local and systemic side effects.

Articaine as an alternative in lidocaine allergy: Case report of a seventy year old male patient

INTRODUCTION

Allergy to lidocaine is extremely rare but if it occurs, one should switch to an alternative drug and discontinue the use of lidocaine so that adverse consequences do not occur.

PRESENTATION OF CASE

We present the case of a 70 year old male patient who had come to our department to undergo extraction of his decayed teeth under local anesthesia.

DISCUSSION

He had history of allergy to lidocaine. Type IV hypersensitivity to lidocaine was confirmed by positive skin prick testing to the drug. Skin prick testing was also performed for articaine that was available with us, and the test was found to be negative without any wheal or flare reaction even after 72 h. Thus it was confirmed that he was non-allergic to articaine and successfully underwent exodontia by using the same.

CONCLUSION

Articaine can be a suitable alternative in patients with true lignocaine allergy and vice-versa. No cross-reactivity has been reported between lidocaine and articaine so far. However, the number of cases reported in the past are limited, hence more cases are required in the future to prove its authenticity.

Comparative Assessment of Antibacterial Efficacy of Commercially Available Different Dental Gels: An In-vitro Study

BACKGROUND

The topical routes of administering drugs have certain visible advantages, such as the direct application of a drug to the site of action and persistence of action for a prolonged duration. More stability and better application property of gel allow its use for topical application.

OBJECTIVES

To determine and compare antibacterial efficacy of commercially available different dental gels.

METHODS

For the evaluation of the antibacterial efficacy of commercially available different antiseptic gels on Streptococcus mutans and Lactobacillus acidophilus, well-diffusion method was used. To assess the antibacterial efficacy after incubation in an appropriate culture medium, diameter of zone of inhibition was measured.

RESULTS

Maximum zone of inhibition was found with Cure next gel (40 mm,40mm) followed by Hexigel (30 mm, 21mm), Mucopain (17 mm, 17mm), and Dologel (7 mm, 16mm) against S. mutans and L. acidophilus, respectively. Analysis of variance (ANOVA) and Post Hoc Test were used to analyze results statistically. The difference between commercially available different dental gels was statistically significant (P < 0.001) at a 5%.

CONCLUSION

In the present study, it was observed that Curenext gel was more effective, followed by Hexigel, Mucopain gel, and Dologel on S. Mutans and L. Acidophilus.

Dual Oral Tissue Adhesive Nanofiber Membranes for pH-Responsive Delivery of Antimicrobial Peptides

Bioadhesive membranes with controllable and reversible underwater adhesion are desirable for several biomedical applications ranging from biosensing, drug/therapeutic delivery, and tissue regeneration. Here, we present dual soft mucosal and hard bone/enamel tissue adhesive nanofiber membranes composed of chitosan and pectin derivatives for pH-controlled delivery of antimicrobial peptides (AMPs) in the oral cavity. Ex vivo testing with porcine esophagus (soft mucosal mimic) indicated a 2-fold increase in the mucoadhesion of chitosan membranes with 0.05 wt % oxidized pectin coating, while the uncoated membranes exhibited 3-4-fold stronger adhesion to hydroxyapatite discs (enamel/hard bone mimic) compared to the coated membranes. The former is attributed to a synergistic interaction of surface nanofiber topography, intermolecular hydrogen bonding, and aldehyde-amine chemistry between surface polar groups and mucosal proteins, while the latter may arise from electrostatic interactions between cationic amines (-NH₃⁺) in chitosan and anionic phosphates (-PO₄^3-) in hydroxyapatite. Further, the dual hard-soft oral tissue adhesive nanofiber membranes loaded with cationic amphipathic AMPs (D-GL13K and IDR-1018) elicited pH-responsive AMP delivery and antimicrobial action comparable to chlorhexidine (CHX) against oral streptococci. Concurrently, the AMP loaded membranes were cytocompatible to both soft epithelial tissue-derived human oral keratinocytes and hard calvarial murine pre-osteoblast cells. We envision these membranes to function as adhesive gingival grafts and guided bone regeneration (GBR) membranes at the hard-soft tissue interface while simultaneously protecting against oral infections.

Brief Motivational Interventions: Strategies for Successful Management of Complex, Nonadherent Dental Patients

Motivational interviewing (MI) is an evidence-based approach to resolving patient ambivalence to change. MI techniques can be effectively used by dentists in assessing and managing substance use risk and may add minimal time to the patient interview. Although MI's greatest utility has been in the area of improving general oral hygiene in order to reduce caries and other preventable conditions, its use in addressing controlled substance risk is well established in other health care disciplines. These techniques do not require special training in mental health assessment and can be effectively used by dentists and dental hygienists.

The pharmacological management of dental pain

Introduction: Dental pain is primarily treated by dentists and emergency medicine clinicians and may occur because of insult to the tooth or oral surgery. The dental impaction pain model (DIPM) has been widely used in clinical studies of analgesic agents and is generalizable to many other forms of pain.Areas Covered: The authors discuss the DIPM, which has allowed for important head-to-head studies of analgesic agents, such as acetaminophen, nonsteroidal anti-inflammatory drugs (NSAIDs), opioids, and combinations. Postsurgical dental pain follows a predictable trajectory over the course of one to 3 days. Dental pain may have odontic origin or may be referred pain from other areas of the body.Expert opinion: Pain following oral surgery has sometimes been treated with longer-than-necessary courses of opioid therapy. Postsurgical dental pain may be moderate to severe but typically resolves in a day or two after the extraction. Opioid monotherapy, rarely used in dentistry but combination therapy (opioid plus acetaminophen or an NSAID), was sometimes used as well as nonopioid analgesic monotherapy. The dental impaction pain model has been valuable in the study of analgesics but does not address all painful conditions, for example, pain with a neuropathic component.

Benzocaine: Review on a Drug with Unfold Potential

Benzocaine is well-known for its role as an anesthetic agent and largely used in oral ulcers, ear pain and dental complications. Along with lidocaine and other local anesthetics, benzocaine has marked it as an anesthetic agent in surgical procedures and as Na+ channels blocker, as well. Analogues of benzocaine have been found to possess biological potentials including antibacterial, antifungal and anti-cancer. Some derivatives were found to have conspicuous action against tuberculosis. The current review focuses to explore the century-long potential of the molecule and its analogs that have appeared in the literature. Furthermore, highlighting the biological potential of benzocaine and its analogues shall open-up new dimensions of future research to design more potent analogues.

True Allergy to Amide Local Anesthetics: A Review and Case Presentation

Adverse reactions to local anesthetics are usually a reaction to epinephrine, vasovagal syncope, or overdose toxicity. Allergic reactions to local anesthetics are often attributed to additives such as metabisulfite or methylparaben. True allergic reactions to amide local anesthetics are extremely rare but have been documented. Patients with true allergy to amide local anesthetics present a challenge to the dental practitioner in providing adequate care with appropriate intraoperative pain management. Often, these patients may be treated under general anesthesia. We report a case of a 43-year-old female patient that presented to NYU Lutheran Medical Center Dental Clinic with a documented history of allergy to amide local anesthetics. This case report reviews the use of 1% diphenhydramine with 1:100,000 epinephrine as an alternative local anesthetic and reviews the relevant literature.

Lack of Methemoglobin Elevations After Topical Applications of Benzocaine Alone or Benzocaine Plus Tetracaine to the Oral Mucosa

PURPOSE

This study evaluated changes in methemoglobin and oxygen saturation concentrations after the administration of recommended doses of 14% benzocaine alone or 14% benzocaine combined with 2% tetracaine.

METHODS

American Society of Anesthesiology class 1 and 2 subjects (n = 40) were enrolled in this modified crossover study. Subjects were administered 0.2 mL of 14% benzocaine alone, 0.2 mL of 14% benzocaine plus 2% tetracaine, or 0.4 mL of 14% benzocaine plus 0.2% benzocaine to their cheek mucosa. Venous blood (5 mL) was drawn from the antecubital fossa before and 60 minutes after drug application for methemoglobin analyses. Oxygen saturation was also recorded via pulse oximetry at baseline and every 10 minutes through 60 minutes after drug application.

FINDINGS

Methemoglobin and oxygen saturation levels did not change from baseline after the administration of benzocaine alone or when combined with tetracaine.

IMPLICATIONS

Recommended doses of benzocaine or benzocaine combined with tetracaine when applied to the cheek mucosa do not induce even clinically insignificant elevations in methemoglobin levels. Metered dosing, such as that used in this study, can help avoid this overdose phenomena with these drugs. ClinicalTrials.gov identifier: NCT02908620.

Effect of Topical Anesthesia Using an Adhesive Patch and Anesthetic Solution

We analyzed trigeminal somatosensory evoked potentials (TSEP) to the alveolar mucosa to investigate the efficacy of an amide local anesthetic, 2% lidocaine hydrochloride with 12.5 μg/mL epinephrine (Lido treatment) as a topical anesthetic. Eighteen consenting healthy adult volunteers were enrolled. A volume of 0.06 mL of Lido, 0.06 g of 20% benzocaine, or 0.06 mL of physiological saline (control) was instilled onto a hemostatic adhesive patch, which was then applied to the alveolar mucosa at the maxillary right canine for 5 minutes. An electrical stimulus approximately 5 times that of the sensory threshold was applied using a surface stimulation electrode. The trigeminal somatosensory evoked potential was recorded immediately, 5 minutes, and 10 minutes after removal of the patch. Positive P125 and P310 peaks and negative N100 and N340 peaks were observed as a result of the electrical stimulation. A significant decrease in the percentage change in amplitude of N100-P125 was observed in the Lido treatment immediately, 5 minutes, and 10 minutes after patch removal. In the Lido treatment, trigeminal somatosensory evoked potential amplitude at N100-P125 decreased significantly, suggesting that topical anesthesia produced by an amide local anesthetic may have a topical anesthetic effect as potent as that produced by an ester local anesthetic.

Effectiveness of benzocaine in reducing deep cavity restoration and post-extraction stress in dental patients

Objectives:

To investigate the effectiveness of topical anesthetic, 20% benzocaine in relieving pain and stress in patients following deep cavity restoration and extraction of teeth under local anesthesia (LA).

Methods:

A prospective clinical trial was conducted from October 2014 until April 2015 at Taibah University, Al Madinah Al Munawarah, Kingdom of Saudi Arabia. Forty-five patients were included in the 20% benzocaine group, and 46 in the normal saline group. Evaluation of the dental stress was made pre-operatively and immediately post-operative treatment using the visual analogue scale (VAS). Furthermore, discomfort of the injections were recorded by the patients after each treatment on standard 100 mm VAS, tagged at the endpoints with “no pain” (0 mm) and “unbearable pain” (100 mm).

Results:

There were statistically significant differences between the mean stress scores for patients in the benzocaine and normal saline groups post-operatively (p=0.002). There were significant differences between the mean pain scores for patients in the post buccal injection (p=0.001), post palatal injection (p=0.01), and the post inferior alveolar nerve block groups (p=0.02). Buccal, palatal, and inferior alveolar nerve block injections were more painful for patients in the normal saline group than the benzocaine group.

Conclusion:

This investigation has demonstrated that post-operative stress associated with deep cavity restoration and dental extractions under LA can be reduced by the application of topical anesthetic (20% benzocaine) at the operative site for intra-oral injections.

Effect of 5% benzocaine gel on relieving pain caused by fixed orthodontic appliance activation. A double-blind randomized controlled trial

AIM

To compare the effectiveness of 5% benzocaine gel and placebo gel on reducing pain caused by fixed orthodontic appliance activation.

SETTING AND SAMPLE POPULATION

Thirty subjects (15-25 years) undergoing fixed orthodontics.

METHODS AND MATERIALS

A randomized, double-blind, placebo-controlled and cross-over clinical trial study was conducted. Subjects were asked to apply a placebo gel and 5% benzocaine gel, exchangeable in two consecutive appointments, twice a day for 3 days and mark their level of pain on a VAS scale. The pain severity was evaluated by means of Mann-Whitney U-test for comparing two gel groups, Kruskal-Wallis nonparametric test for overall differences and post hoc test of Dunnett for paired multiple comparisons. p-value was assigned <0.05.

RESULTS

The overall mean value of pain intensity for benzocaine and placebo gels was 0.89 and 1.15, respectively. The Mann-Whitney U-test indicated that there was no significant difference between overall pain in both groups (mean difference = 0.258 p ˂ 0.21). For both groups, pain intensity was significantly lower at 2, 6 and 24 h compared with pain experienced at days 2, 3 and 7.

CONCLUSION

Benzocaine gel caused a decrease in pain perception at 2 h compared with placebo gel. Peak pain intensity was at 2 h for placebo gel and at 6 h for benzocaine gel, followed by a decline in pain perception from that point to day 7 for both gels.

Benzocaine-Induced Methemoglobinemia: A Case Report

Topical anesthetics, such as benzocaine, have been reported to cause methemoglobinemia, in which hemoglobin is unable to release oxygen effectively to body tissues. The pathophysiology, symptoms, and treatment of a 46-year-old patient are examined.

An Atypical Case of Methemoglobinemia due to Self-Administered Benzocaine

Acquired methemoglobinemia is an uncommon hemoglobinopathy that results from exposure to oxidizing agents, such as chemicals or medications. Although, as reported in the adult population, it happens most often due to prescribed medication or procedural anesthesia and not due to easily accessed over-the-counter medications, the authors will describe an otherwise healthy male adult with no known medical history and no prescribed medications, who presented to the emergency department reporting generalized weakness, shortness of breath, headache, dizziness, and pale gray skin. In addition, the patient reported that he also had a severe toothache for several days, which he had been self-treating with an over-the-counter oral benzocaine gel. Ultimately, the diagnosis of methemoglobinemia was made by clinical history, physical examination, and the appearance of chocolate-colored blood and arterial blood gas (ABG) with cooximetry. After 2 mg/kg of intravenous methylene blue was administered, the patient had complete resolution of all signs and symptoms. This case illustrates that emergency physicians should be keenly aware of the potential of toxic hemoglobinopathy secondary to over-the-counter, nonprescribed medications. Discussion with patients regarding the dangers of inappropriate use of these medicines is imperative, as such warnings are typically not evident on product labels.

A double-blind, randomized clinical study to determine the efficacy of benzocaine 10% on histamine-induced pruritus and UVB-light induced slight sunburn pain

INTRODUCTION

This study aims to explore the efficacy of the topical application of 10% benzocaine for treating pruritus and pain as compared to vehicle ointment.

METHODS

Twenty male subjects were treated in a randomized double-blind fashion with the investigational medicinal product (IMPD) and vehicle. Immediately after the injection of 100 µg histamine on both arms, subjects received topical treatment and pruritus was subsequently assessed with visual analogue scale (VASpruritus) and Eppendorfer questionnaire. Ultraviolet B radiation (UVB) was administered on the back to induce slight sunburn. Twelve hours after UVB application again the IMPD was applied on the right or left upper back and vehicle on the other side and pain related to sunburn was measured with VASpain and pressure algometry.

RESULTS

A trend towards better reduction of pruritus was shown for benzocaine in VASpruritus. For the VASpain significant differences in group comparison (p = 0.02) were observed. Algometer measurements showed onset of pain reduction in the verum group after 20 min whereas in the vehicle-treated area pain relief occurred only after 60 min after application.

CONCLUSIONS

The topically administered ointment containing 10% benzocaine was found superior over vehicle for treating pain, but not pruritus.

Identification of N-Hydroxy-para-aminobenzoic acid in a cyanotic child after benzocaine exposure

CONTEXT

Methemoglobinemia (MetHb) after exposure to benzocaine (BZC) has been reported for more than 50 years, however the pathophysiologic mechanism has not been previously established. Direct administration of BZC to blood does not produce MetHb. After topical use, due to the lipophilicity and rapid acetylation in the tissue, little BZC reaches the liver for hepatic biotransformation. However, isolated human livers have been shown to produce MetHb forming N-hydroxyl metabolites from BZC. We report a case of BZC-induced MetHb with the first identification and quantification of the reactive metabolite responsible for the oxidative stress: N-Hydroxy-Para-amino benzoic acid (N-OH-PABA).

CASE DETAILS

An 8 year old male was admitted to a hospital for an appendectomy. Several applications of BZC spray were used during multiple attempts at nasogastric tube placement. In various attempts to achieve local anesthesia, benzocaine spray was used in both nares and through the mouth aimed at the posterior oropharynx. The patient subsequently became cyanotic with an initial MetHb level of 32.9 %. Methylene blue was administered and the patient promptly responded with resolution of cyanosis. Blood taken within 20 min of the initial symptoms contained benzocaine (5.2ug/mL), bupivacaine (740ng/mL), lidocaine (530ng/mL), acetaminophen (12ug/mL), midazolam (60ng/mL), PABA and N-OH-PABA (35ng/mL). Serum was analyzed using Liquid Chromatography- Quadrupole Time-of-Flight Mass Spectrometry. Mass spectrometry was done using an electrospray ionization source run in negative and positive polarities. A reference standard for N-OH-PABA was synthesized for confirmation and quantification.

DISCUSSION

The rare and idiopathic nature of methemoglobinemia after benzocaine use has made study of the pathophysiologic mechanism in humans difficult. Lack of understanding has brought calls for restriction of use of the widely used medication that may not be based on evidence. Our case presents several unique features: 1) benzocaine absorption after topical administration was documented with serum concentrations 2) confirmation of an in vivo formation of MetHb-forming n-hydroxyl-metabolite after benzocaine use and 3) the documentation of N-OH-PABA in humans within 20 min of MetHb post-benzocaine administration.