Benzocaine

Last updated

Benzocaine
Benzocaine.svg
Benzocaine-from-xtal-3D-balls.png
Clinical data
Trade names Anbesol, Lanacane, Orajel, others
AHFS/Drugs.com
Routes of
administration 		Topical, Oral
ATC code
Legal status
Legal status
  • AU: S4 (Prescription only)/ Schedule 2 [1]
  • UK:GSL, P
  • US: OTC
Identifiers
  • Ethyl 4-aminobenzoate
CAS Number
PubChem CID
DrugBank
ChemSpider
UNII
KEGG
ChEBI
ChEMBL
CompTox Dashboard (EPA)
ECHA InfoCard 100.002.094 OOjs UI icon edit-ltr-progressive.svg
Chemical and physical data
Formula C9H11NO2
Molar mass 165.192 g·mol−1
3D model (JSmol)
  • O=C(OCC)c1ccc(N)cc1
  • InChI=1S/C9H11NO2/c1-2-12-9(11)7-3-5-8(10)6-4-7/h3-6H,2,10H2,1H3
  • Key:BLFLLBZGZJTVJG-UHFFFAOYSA-N

Benzocaine, sold under the brand name Orajel amongst others, is a local anesthetic, belonging to the amino ester drug class, commonly used as a topical painkiller or in cough drops. It is the active ingredient in many over-the-counter anesthetic ointments such as products for oral ulcers. It is combined with antipyrine to form A/B ear drops. In the US, products containing benzocaine for oral application are contraindicated in children younger than two years old. [2] [3]

Contents

It was first synthesised in 1890 in Germany and approved for medical use in 1902. [4]

Medical uses

Benzocaine is indicated to treat a variety of pain-related conditions. It may be used for:

Examples of combination medications of benzocaine include:

Other uses

Jiffy Toothache Drops bottle (7.75% Benzocaine) Jiffy Toothache Drops bottle.jpg
Jiffy Toothache Drops bottle (7.75% Benzocaine)

Benzocaine is used as a key ingredient in numerous pharmaceuticals:

Available forms

Benzocaine can come in a variety of preparations including:

Oral preparations:

Topical preparations:

Otic preparations:

Side effects

Benzocaine is generally well tolerated and non-toxic when applied topically as recommended. [21]

However, there have been reports of serious, life-threatening adverse effects (e.g., seizures, coma, irregular heart beat, respiratory depression) with over-application of topical products or when applying topical products that contain high concentrations of benzocaine to the skin. [22]

The topical use of higher concentration (10–20%) benzocaine products applied to the mouth or mucous membranes has been found to be a cause of methemoglobinemia, a disorder in which the amount of oxygen carried by the blood is greatly reduced. [23]

Benzocaine may cause allergic reactions. [24] [25] [26] [27] These include:

Chemistry

Benzocaine is the ethyl ester of p-aminobenzoic acid (PABA). It can be prepared from PABA and ethanol [29] by Fischer esterification or via the reduction of ethyl p-nitrobenzoate. Benzocaine is sparingly soluble in water; it is more soluble in dilute acids and very soluble in ethanol, chloroform, and ethyl ether. The melting point of benzocaine is 88–92 °C, [30] and the boiling point is about 310 °C. [31] The density of benzocaine is 1.17 g/cm3.

Synthesis

Benzocaine can be prepared by esterification using 4-aminobenzoic acid and ethanol. [32] [33] It can also be prepared by reduction of ethyl 4-nitrobenzoate to the amine. [34] [35] In industrial practice, the reducing agent is usually iron and water in the presence of a little acid. [36]

History

Benzocaine was first synthesized in 1890 by the German chemist Eduard Ritsert (1859–1946), [37] in the town of Eberbach [38] and introduced to the market in 1902 under the name "Anästhesin". [39] [40]

Society and culture

Benzocaine is found, particularly in Britain, as an additive in street cocaine and also as a bulking agent in "legal highs". [41] Benzocaine gives a numbing effect similar to cocaine and as a bulking and binding agent it can not be detected once mixed. It is the most popular cutting agent worldwide. [42]

Veterinary uses

Bath solutions of benzocaine and its derivatives are commonly used to anesthetize amphibians for surgery. [43] [44] Benzocaine-based anesthetics are potent and highly effective for both anesthesia and euthanasia in amphibians. [45]

References

  1. ↑ "Therapeutic Goods (Poisons Standard— June 2025) Instrument 2025" (pdf). Therapeutic Goods Administration (TGA). May 2025. Retrieved August 31, 2025.
  2. ↑ "Safety Alerts for Human Medical Products - Oral Over-the-Counter Benzocaine Products: Drug Safety Communication - Risk of Serious and Potentially Fatal Blood Disorder". U.S. Food and Drug Administration (FDA). Archived from the original on September 7, 2018. Retrieved May 26, 2018.
  3. ↑ "Safety Information on Benzocaine-Containing Products". U.S. Food and Drug Administration (FDA). June 25, 2018. Retrieved December 1, 2025.
  4. ↑ Fischer J, Ganellin CR (2006). Analogue-based Drug Discovery. John Wiley & Sons. p. 475. ISBN   978-3-527-60749-5.
  5. 1 2 AHFS Drug Information 2007. McEvoy GK, ed. Benzocaine. Bethesda, MD: American Society of Health-System Pharmacists; 2007: 2844-5.
  6. ↑ Sultan Healthcare. Topex metered spray (benzocaine 20%) prescribing information. Englewood, NJ; 2006.
  7. ↑ Benzocaine topical
  8. ↑ "Antipyrine-Benzocaine Otic: MedlinePlus Drug Information". medlineplus.gov. Retrieved March 28, 2023.
  9. ↑ "Cepacol Sore Throat (Benzocaine-Menthol) Mucous Membrane: Uses, Side Effects, Interactions, Pictures, Warnings & Dosing - WebMD". www.webmd.com. Retrieved March 28, 2023.
  10. ↑ STING-KILL - benzocaine and menthol solution
  11. ↑ "'Longer-lasting' condom launched". BBC News. June 17, 2002.
  12. ↑ Garner D (December 15, 2002). "Endurance Condoms". The New York Times.
  13. ↑ Eslamian L, Borzabadi-Farahani A, Edini HZ, Badiee MR, Lynch E, Mortazavi A (September 2013). "The analgesic effect of benzocaine mucoadhesive patches on orthodontic pain caused by elastomeric separators, a preliminary study". Acta Odontologica Scandinavica. 71 (5): 1168–1173. doi: 10.3109/00016357.2012.757358 . PMID   23301559. S2CID   22561192.
  14. ↑ "Produkty | PUDRODERM" (in Polish). Archived from the original on October 18, 2016. Retrieved May 9, 2014.
  15. ↑ "Cepacol". Cepacol.com. Retrieved June 2, 2015.
  16. ↑ "Ultra Chloraseptic Anaesthetic Throat Spray 0.71% - Summary of Product Characteristics (SmPC) - (eMC)". www.medicines.org.uk. Archived from the original on May 5, 2018. Retrieved May 5, 2018.
  17. ↑ "Topex Metered Spray-Sultan Healthcare". Sultanhc.com. Retrieved June 2, 2015.
  18. ↑ "Orajel - Oral Care for the Whole Family". Orajel.com. May 11, 2015. Retrieved June 2, 2015.
  19. ↑ "Kank-A | Canker Sore Treatment & Pain Relief" . Retrieved November 29, 2023.
  20. ↑ "Colgate Orabase Paste with Benzocaine | Indications | Dental Products". Colgateprofessional.com. Retrieved June 2, 2015.
  21. ↑ Lexicomp Online, Adult and Pediatric Lexi-Drugs Online, Hudson, Ohio: Lexi-Comp, Inc.; 2013; April 15, 2013.
  22. ↑ "Risk of serious and potentially fatal blood disorder prompts FDA action on oral over-the-counter benzocaine products used for teething and mouth pain and prescription local anesthetics". U.S. Food and Drug Administration (FDA). May 23, 2018. Archived from the original on September 26, 2025. Retrieved November 30, 2025.
  23. ↑ Shua-Haim JR, Gross JS (May 1995). "Methemoglobinemia toxicity from topical benzocaine spray". Journal of the American Geriatrics Society. 43 (5): 590. doi: 10.1111/j.1532-5415.1995.tb06117.x . PMID   7730550. S2CID   19563675.
  24. ↑ "Allergy to Benzocaine" (PDF). Archived from the original (PDF) on March 20, 2014. Retrieved March 20, 2014.
  25. ↑ Sidhu SK, Shaw S, Wilkinson JD (June 1999). "A 10-year retrospective study on benzocaine allergy in the United Kingdom". American Journal of Contact Dermatitis. 10 (2): 57–61. doi:10.1016/s1046-199x(99)90000-3. PMID   10357712.
  26. ↑ González-Rodríguez AJ, Gutiérrez-Paredes EM, Revert Fernández Á, Jordá-Cuevas E (March 2013). "Allergic contact dermatitis to benzocaine: the importance of concomitant positive patch test results" (PDF). Actas Dermo-Sifiliograficas. 104 (2): 156–158. doi:10.1016/j.ad.2011.07.023. PMID   22551703. Archived from the original (PDF) on March 3, 2016. Retrieved March 20, 2014.
  27. ↑ Goldman L (February 5, 2008). "Go easy on medicated lotions, creams, gels". CNN. Retrieved March 20, 2014.
  28. 1 2 Cetylite Industries. Cetacaine (benzocaine 14%, tetracaine 2% and butamben 2%) spray, gel and liquid prescribing information. Pennsauken, NJ; 2006 Sept.
  29. ↑ Demare P, Regla I (2012). "Synthesis of Two Local Anesthetics from Toluene: An Organic Multistep Synthesis in a Project-Oriented Laboratory Course". Journal of Chemical Education. 89 (1): 147. Bibcode:2012JChEd..89..147D. doi:10.1021/ed100838a.
  30. ↑ "Benzocaine". PubChem. U.S. National Library of Medicine. Retrieved March 27, 2023.
  31. ↑ D'Ans-Lax, Taschenbuch für Chemiker und Physiker. Organische Verbindungen (4th ed.). Berlin: Springer Verlag. 1983. ISBN   3-540-12263-X.
  32. ↑ Salkowski H (1895). "Ueber Esterbildung bei aromatischen Amidosäuren". Berichte der Deutschen Chemischen Gesellschaft. 28 (2): 1917–1923. doi:10.1002/cber.189502802150.
  33. ↑ Erlenmeyer E, Wanklyn JA (1865). "Ueber das durch Einwirkung von Jodwasserstoff auf Mannit beziehungsweise auf Melampyrin (Dulcit) entstehende β Hexyljodür und einige seiner Derivate". Annalen der Chemie und Pharmacie. 135 (2): 129–151. doi:10.1002/jlac.18651350202.
  34. ↑ Limpricht H (1898). "Ueber die Verbindungen aus Benzoylchlorid oder Phtalylchlorid und den Estern der drei Oxybenzoësäuren". Justus Liebig's Annalen der Chemie. 303 (3): 274–289. doi:10.1002/jlac.18983030303.
  35. ↑ Adams R, Cohen FL (1928). "Ethyl p-aminobenzoate". Organic Syntheses . 8: 66; Collected Volumes, vol. 1, p. 240.
  36. ↑ Ali SL (1983). Benzocaine. Analytical Profiles of Drug Substances. Vol. 12. Academic Press. pp. 73–104. doi:10.1016/S0099-5428(08)60164-1. ISBN   978-0-12-260812-4.
  37. ↑ Biography of Eduard Ritsert (in German): Deutsche Biographie: Ritsert, Eduard.
  38. ↑ "100 years of Dr. Ritsert". Dr. Ritsert Pharma. Archived from the original on September 9, 2017. Retrieved March 14, 2010.
  39. ↑ Auterhoff H (1968). Lehrbuch der pharmazeutischen Chemie. Stuttgart, Germany: Wissenschaftliche Verlagsgesellschaft.
  40. ↑ Ritsert E (1925). "Über den Werdegang des Anästhesins" [On the development of Anaesthetics]. Pharmazeutische Zeitung (in German). 60: 1006–1008. See also: Friedrich C, Klimonow M (December 2014). "150. Geburtstag: Eduard Ritsert und das Anaesthesin" [150th birthday: Eduard Ritsert and Anästhetsin [Benzocaine]]. Pharmazeutische Zeitung Online (in German). Archived from the original on March 20, 2014. First published clinical study demonstrating the efficacy of benzocaine: von Noorden C (1902). "Ueber para-Aminobenzoesäure-Ester als locales Anästhetikum" [On [an] ester of para-aminobenzoic acid as a local anaesthetic]. Klinische Wochenschrift (in German). 39: 373–375.
  41. ↑ "Drug war targets cutting agents". BBC News. August 9, 2010.
  42. ↑ "Drug prices: All cut up: Cocaine is cheaper, but weaker". The Economist . August 11, 2012.
  43. ↑ Guénette SA, Giroux MC, Vachon P (2013). "Pain perception and anaesthesia in research frogs". Experimental Animals. 62 (2): 87–92. doi: 10.1538/expanim.62.87 . PMID   23615302.
  44. ↑ "Amphibian Anesthesia — Research at Penn State". PennState Animal Resource Program. State College, U.S.: The Pennsylvania State University. November 8, 2010. Archived from the original on November 3, 2018. Retrieved August 24, 2017.
  45. ↑ Barros AL, Lima AP, Fachin-Espinar MT, Nunez CV (2020). "Evaluation of benzocaine-based anesthetic gel in anuran skins extracts: A case study using the frog Lithodytes lineatus (Anura: Leptodactylidae)". PLOS ONE. 15 (12) e0243654. Bibcode:2020PLoSO..1543654B. doi: 10.1371/journal.pone.0243654 . PMC   7723253 . PMID   33290419.
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