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Special Alerts
Topical Anesthetic Use for Cosmetic Procedures: Public Health Advisory − February, 2007
The Food and Drug Administration (FDA) is notifying consumers and healthcare professionals of potential life-threatening side effects associated with the use of topical anesthetics prior to cosmetic procedures. Gels, creams, and ointments containing topical anesthetics (eg, lidocaine, tetracaine, benzocaine, prilocaine) are available as prescription and over-the counter products for a variety of uses, including numbing skin prior to cosmetic procedures. Potential hazards exist with anesthetic use. Topical application can result in high systemic levels and lead to toxic effects (eg, irregular heart beats, seizures, coma, respiratory depression, death). At risk are consumers, particularly those without the supervision of trained professionals, who apply large amounts of anesthetics (or cover large areas of the skin), leave these products on for long periods of time, or use materials, wraps, or dressings to cover the skin after anesthetic application. Application to areas of skin irritation, rash, and broken skin may also increase the risk of systemic absorption. The degree of systemic exposure following topical application is highly variable between patients; however, all of these practices listed may increase the degree of systemic absorption and should be avoided. The FDA is aware of two fatalities (presenting initially as seizures and then coma) following use of highly concentrated compounded topical anesthetics applied to legs and subsequently wrapped with plastic wrap to lessen pain of laser hair removal. The FDA is recommending that if topical anesthetics are needed prior to medical or cosmetic procedures, consumers ask their healthcare provider for instructions on safe use of these products, use only FDA-approved products, and use products with the lowest amount of anesthetic while applying the least amount possible to relieve pain. If a high degree of pain is expected that is not controlled by appropriate amounts of topical anesthetics, consumers should ask their healthcare provider for alternative techniques for pain control.
Additional information can be found at http://www.fda.gov/medwatch/safety/2007/safety07.htm#Anesthetics
Health Canada Issues Important Safety Information to Hospitals − November, 2006
Methemoglobinemia, an uncommon adverse reaction to benzocaine, results in an impaired ability of red blood cells to bind and carry oxygen. This potentially life-threatening reaction has been well documented, however cases continue to be reported to regulatory agencies (including Health Canada) and in the medical literature. For this reason, Health Canada has issued a reminder to healthcare professionals that benzocaine sprays must be used judiciously to minimize the risk of methemoglobinemia. Of note, almost all reported cases have been associated with higher concentration (14% to 20% benzocaine) spray products used in the mouth and on other mucous membranes. Alternatives to benzocaine sprays, such as topical lidocaine preparations, should be considered for patients at higher risk of this reaction.
Healthcare providers are reminded to carefully evaluate patients for predisposing risk factors for benzocaine-induced methemoglobinemia. Risk factors include mucosal damage or inflammation at the application site, use in infants, concomitant use of other oxidizing agents, heart disease, malnutrition, and deficiencies in certain enzyme, such as glucose-6-phosphate dehydrogenase or hemoglobin reductase. The number of sprays administered and the length of each spray should be monitored and recorded. The minimum quantity of spray to achieve the desired effect should be used. All patients should be monitored for signs and symptoms of methemoglobinemia (eg, cyanosis, weakness, dyspnea, tachycardia).
The classical clinical finding of methemoglobinemia is chocolate brown-colored arterial blood. However, suspected cases should be confirmed by co-oximetry, which yields a direct and accurate measure of methemoglobin levels. Standard pulse oximetry readings or arterial blood gas values are not reliable. Clinically significant methemoglobinemia requires immediate treatment.
Health Canada has urged the distribution of this notice to Departments of Surgery, Emergency Medicine, Pharmacy, Pediatrics, Anesthesia, Internal Medicine, Nursing, Dentistry, Otolaryngology, and Gastroenterology.
Additional information may be found at: http://www.hc-sc.gc.ca/dhp-mps/medeff/advisories-avis/prof/2006/benzocaine_sprays-vaporisateurs_nth-aah_e.html
Pronunciation
(BEN zoe kane)
Generic Available (U.S.)
Yes: Lozenge, otic drops
Index Terms
Brand Names: U.S.
Brand Names: Canada
Pharmacologic Category
Pharmacologic Category Synonyms
Use: Labeled Indications
Temporary relief of pain associated with pruritic dermatosis, pruritus, minor burns, acute congestive and serous otitis media, swimmer's ear, otitis externa, bee stings, insect bites; mouth and gum irritations (toothache, minor sore throat pain, canker sores, dentures, orthodontia, teething, mucositis, stomatitis); sunburn; hemorrhoids; anesthetic lubricant for passage of catheters and endoscopic tubes
Use: Dental
Ester-type topical local anesthetic for temporary relief of pain associated with toothache, minor sore throat pain, and canker sore
Pregnancy Risk Factor
C
Pregnancy Considerations
Reproduction studies have not been conducted.
Lactation
Excretion in breast milk unknown/use caution
Contraindications
Hypersensitivity to benzocaine, other ester-type local anesthetics, or any component of the formulation; secondary bacterial infection of area; ophthalmic use; otic preparations are also contraindicated in the presence of perforated tympanic membrane
Warnings/Precautions
Concerns related to adverse effects:
• Methemoglobinemia: Has been reported following topical use (rare), particularly with higher concentration (14% to 20%) spray formulations applied to the mouth or mucous membranes. When applied as a spray to the mouth or throat, multiple sprays (or sprays of longer than indicated duration) are not recommended. Use caution with breathing problems (asthma, bronchitis, emphysema, in smokers), inflamed/damaged mucosa, heart disease, children <6 months of age, and hemoglobin or enzyme abnormalities (glucose-6-phosphodiesterase deficiency, hemoglobin-M disease, NADH-methemoglobin reductase deficiency, pyruvate-kinase deficiency). Alternatives to benzocaine sprays, such as topical lidocaine preparations, should be considered for patients at higher risk of this reaction. The classical clinical finding of methemoglobinemia is chocolate brown-colored arterial blood. However, suspected cases should be confirmed by co-oximetry, which yields a direct and accurate measure of methemoglobin levels. Standard pulse oximetry readings or arterial blood gas values are not reliable. Clinically significant methemoglobinemia requires immediate treatment.
Other warnings/precautions:
• OTC use: When used for self-medication (OTC), notify healthcare provider if condition worsens or does not improve within 7 days, or if swelling, rash, or fever develops. Do not use on open wounds. Avoid contact with the eyes.
Adverse Reactions
Frequency not defined.
Hematologic: Methemoglobinemia
Local: Burning, contact dermatitis, edema, erythema, pruritus, rash, stinging, tenderness, urticaria
Miscellaneous: Hypersensitivity
Drug Interactions
May antagonize actions of sulfonamides
Mechanism of Action
Ester local anesthetic blocks both the initiation and conduction of nerve impulses by decreasing the neuronal membrane's permeability to sodium ions, which results in inhibition of depolarization with resultant blockade of conduction
Pharmacodynamics/Kinetics
Absorption: Topical: Poor to intact skin; well absorbed from mucous membranes and traumatized skin
Metabolism: Hepatic (to a lesser extent) and plasma via hydrolysis by cholinesterase
Excretion: Urine (as metabolites)
Dosage
Note: These are general dosing guidelines; refer to specific product labeling for dosing instructions.
Children ≥4 months: Topical (oral): Teething pain: 7.5% to 10%: Apply to affected gum area up to 4 times daily
Children ≥2 years and Adults:
Topical:
Bee stings, insect bites, minor burns, sunburn: 5% to 20%: Apply to affected area 3-4 times a day as needed. In cases of bee stings, remove stinger before treatment.
Lubricant for passage of catheters and instruments: 20%: Apply evenly to exterior of instrument prior to use.
Topical (oral): Mouth and gum irritation: 10% to 20%: Apply thin layer to affected area up to 4 times daily
Children ≥5 years and Adults: Oral: Sore throat: Allow one lozenge (10-15 mg) to dissolve slowly in mouth; may repeat every 2 hours as needed
Children ≥12 years and Adults: Rectal: Hemorrhoids: 5% to 20%: Apply externally to affected area up to 6 times daily
Adults: Otic: 20%: Instill 4-5 drops into external auditory canal; may repeat in 1-2 hours if needed
Dental Usual Dosing
Relief of pain (toothache, minor sore throat pain, and canker sore): Children ≥2 years and Adults: Topical (oral): 10% to 20%: Apply thin layer to affected area up to 4 times daily
Administration: Topical
Avoid application to large areas of broken skin, especially in children. When possible, apply to clean, dry area. When administering a spray formulation, the number of sprays administered and the length of each spray should be monitored and recorded.
Monitoring Parameters
Monitor patients for signs and symptoms of methemoglobinemia such as pallor, cyanosis, nausea, muscle weakness, dizziness, confusion, agitation, dyspnea and tachycardia. The classical clinical finding of methemoglobinemia is chocolate brown-colored arterial blood. However, suspected cases should be confirmed by co-oximetry, which yields a direct and accurate measure of methemoglobin levels. Standard pulse oximetry readings or arterial blood gas values are not reliable. Clinically significant methemoglobinemia requires immediate treatment.
Patient Education
Use as directed; do not overuse. Use least amount possible to obtain desired effect. Do not apply when infections are present and do not apply to large areas of broken skin. Do not eat or drink for 1 hour following oral application. Discontinue application and report if swelling of mouth, lips, tongue, or throat occurs; or if skin irritation occurs at application site. When using as a self-medication (OTC), notify prescriber if condition worsens or does not improve within 7 days or if swelling, rash, or fever develops. Report cyanosis (turning blue in color), weakness, problems breathing, or rapid heartbeat immediately. Pregnancy/breast-feeding precautions: Inform prescriber if you are pregnant. Consult prescriber if breast-feeding.
Dental Health: Effects on Dental Treatment
No significant effects or complications reported
Dental Health: Vasoconstrictor/Local Anesthetic Precautions
No information available to require special precautions
Dental Comment
Health Canada has issued a reminder to healthcare professionals that benzocaine sprays must be used judiciously to minimize the risk of methemoglobinemia. Almost all reported cases have been associated with higher concentration (14% to 20% benzocaine) spray products used in the mouth and on other mucous membranes. Alternatives to benzocaine sprays, such as topical lidocaine preparations, should be considered for patients at higher risk of this reaction.
Mental Health: Effects on Mental Status
None reported
Mental Health: Effects on Psychiatric Treatment
None reported
Nursing: Physical Assessment/Monitoring
Monitor for effectiveness of application and adverse reactions. Monitor for cyanosis, dyspnea, weakness, or tachycardia. This could indicate a life-threatening situation. Oral: Use caution to prevent gagging or choking and avoid food or drink for 1 hour. Teach patient possible side effects/appropriate interventions and adverse symptoms to report.
Dosage Forms
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Aerosol, oral spray:
Hurricaine®: 20% (60 mL) [dye free; cherry flavor]
Aerosol, topical spray:
Americaine®: 20% (60 mL)
Dermoplast® Antibacterial: 20% (83 mL) [contains aloe vera, benzethonium chloride, menthol]
Dermoplast® Pain Relieving: 20% (60 mL, 83 mL) [contains menthol]
Foille®: 5% (92 g) [contains chloroxylenol 0.63% and corn oil]
Ivy-Rid®: 2% (83 mL)
Lanacane® Maximum Strength: 20% (120 mL) [contains alcohol]
Solarcaine®: 20% (120 mL) [contains triclosan 0.13%, alcohol 35%]
Combination package (Orajel® Baby Daytime and Nighttime):
Gel, oral [Daytime Regular Formula]: 7.5% (5.3 g)
Gel, oral [Nighttime Formula]: 10% (5.3 g)
Cream, oral:
Benzodent®: 20% (7.5 g, 30 g)
Orajel PM®: 20% (5.3 g, 7 g)
Cream, topical:
Lanacane®: 6% (30 g, 60 g)
Lanacane® Maximum Strength: 20% (30 g)
Gel, oral:
Anbesol®: 10% (7.5 g) [contains benzyl alcohol; cool mint flavor]
Anbesol® Baby: 7.5% (7.5 g) [contains benzoic acid; grape flavor]
Anbesol® Jr.: 10% (7 g) [contains benzyl alcohol; bubble gum flavor]
Anbesol® Maximum Strength: 20% (7.5 g, 10 g) [contains benzyl alcohol]
Dentapaine: 20% (11 g) [contains clove oil]
HDA® Toothache: 6.5% (15 mL) [contains benzyl alcohol]
Hurricaine®: 20% (5 g) [dye free; wild cherry flavor]; (30 g) [dye free; mint, pina colada, watermelon, and wild cherry flavors]
Kanka® Soft Brush™: 20% (2 mL) [packaged in applicator with brush tip]
Little Teethers®: 7.5% (9.4 g) [cherry flavor]
Orabase® with Benzocaine®: 20% (7 g) [contains ethyl alcohol 48%; mild mint flavor]
Orajel®: 10% (5.3 g, 7 g, 9.4 g)
Orajel® Baby Teething: 7.5% (9.4 g, 11.9 g) [cherry flavor]
Orajel® Baby Teething Nighttime: 10% (5.3 g)
Orajel® Denture Plus: 15% (9 g) [contains menthol 2%, ethyl alcohol 66.7%]
Orajel® Maximum Strength: 20% (5.3 g, 7 g, 9.4 g, 11.9 g)
Orajel® Mouth Sore: 20% (5.3 g, 9.4 g, 11.9 g) [contains benzalkonium chloride 0.02%, zinc chloride 0.1%]
Orajel® Multi-Action Cold Sore: 20% (9.4 g) [contains allantoin 0.5%, camphor 3%, dimethicone 2%]
Orajel® Ultra Mouth Sore: 15% (9.4 g) [contains ethyl alcohol 66.7%, menthol 2%]
Zilactin®-B: 10% (7.5 g)
Gel, topical:
Detane®: 7.5% (15 g)
Liquid, oral:
Anbesol®: 10% (9 mL) [cool mint flavor]
Anbesol® Maximum Strength: 20% (9 mL) [contains benzyl alcohol]
Hurricaine®: 20% (30 mL) [pina colada and wild cherry flavors]
Orajel® Baby Teething: 7.5% (13 mL) [very berry flavor]
Orajel® Maximum Strength: 20% (13 mL) [contains ethyl alcohol 44%, tartrazine]
Liquid, oral drop:
Dent's Maxi-Strength Toothache: 20% (3.7 mL) [contains alcohol 74%]
Rid-A-Pain Dental Drops: 6.3% (30 mL) [contains alcohol 70%]
Liquid, topical:
Chiggertox®: 2% (30 mL)
Outgro®: 20% (9 mL)
Skeeter Stik: 5% (14 mL) [contains menthol]
Tanac®: 10% (13 mL) [contains benzalkonium chloride]
Lozenge: 6 mg (18s) [contains menthol]; 15 mg (10s)
Cepacol® Sore Throat: 10 mg (18s) [contains cetylpyridinium, menthol; cherry, citrus, honey lemon, and menthol flavors]
Cepacol® Sore Throat: 10 mg (16s) [sugar free; contains cetylpyridinium, menthol; cherry and menthol flavors]
Cylex®: 15 mg [sugar free; contains cetylpyridinium chloride 5 mg; cherry flavor]
Mycinettes®: 15 mg (12s) [sugar free; contains sodium 9 mg; cherry or regular flavor]
Thorets: 18 mg (500s) [sugar free]
Trocaine®: 10 mg (40s, 400s)
Ointment, oral:
Anbesol® Cold Sore Therapy: 20% (7.1 g) [contains benzyl alcohol, allantoin, aloe, camphor, menthol, vitamin E]
Red Cross™ Canker Sore: 20% (7.5 g) [contains coconut oil]
Ointment, rectal:
Americaine® Hemorrhoidal: 20% (30 g)
Ointment, topical:
Chiggerex®: 2% (50 g) [contains aloe vera]
Foille®: 5% (3.5 g, 14 g, 28 g) [contains chloroxylenol 0.1%, benzyl alcohol; corn oil base]
Pads, topical:
Sting-Kill: 20% (8s) [contains menthol and tartrazine]
Paste, oral:
Orabase® with Benzocaine: 20% (6 g)
Solution, otic drops:
Oticaine, Otocaine™: 20% (15 mL)
Swabs, oral:
Hurricaine®: 20% (6s, 100s) [dye free; wild cherry flavor]
Orajel® Baby Teething: 7.5% (12s) [berry flavor]
Orajel® Medicated Mouth Sore, Orajel® Medicated Toothache: 20% (8s, 12s) [contains tartrazine]
Zilactin® Toothache and Gum Pain: 20% (8s) [grape flavor]
Swabs, topical:
Sting-Kill: 20% (5s) [contains menthol and tartrazine]
Wax, oral:
Dent's Extra Strength Toothache Gum: 20% (1 g)
Pricing: U.S. (www.drugstore.com)
Gel (Americaine Anesthetic)
20% (28): $22.99
Solution (Oticaine Otic)
20% (15): $13.99
References
Anderson ST, Hajduczek J, and Barker SJ, “Benzocaine-Induced Methemoglobinemia in an Adult: Accuracy of Pulse Oximetry With Methemoglobinemia,” Anesth Analg, 1988, 67(11):1099-101.
Bachmann P, Berthier JC, Storme B, et al, “Methemoglobinemia From Ingestion of Benzocaine. A Case of Pediatric Intoxication,” J Toxicol Clin Exp, 1986, 6(2):123-8.
Guertler AT and Pearce WA, “A Prospective Evaluation of Benzocaine-Associated Methemoglobinemia in Human Beings,” Ann Emerg Med, 1994, 24(4):628-30.
Moore TJ, Walsh CS, and Cohen MR, et al , “Reported Adverse Event Cases of Methemoglobinemia Associated With Benzocaine Products,” Arch Intern Med, 2004, 164(11):1192-6.
Rynn KO, Jahns BE, and Sabbun R, “Acute Myocardial Infarction (AMI) Secondary to Benzocaine-Induced Methemoglobinemia,” Clin Toxicol, 1995, 33(5):495.
Shua-Haim JR and Gross JS, “Methemoglobinemia Toxicity From Topical Benzocaine Spray,” J Am Geriatr Soc, 1995, 43(5):590.
Stein JM and Warfield CA, “Local Anesthetics: Principles of Safe Use,” Hosp Pract (Off Ed), 1983, 18(5):73-8.
International Brand Names
Lexi-Comp.com
Last full review/revision December 2007
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