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Trade namesAnbesol, Lanacane, Orajel, others
  • Ethyl 4-aminobenzoate
Clinical data
Drug classLocal anesthetic (ester)[1]
Main usesMinor skin injury, mouth pain, hemorrhoids, premature ejaculation[2][3]
Side effectsContact dermatitis, methemoglobinemia[2]
  • US: C (Risk not ruled out)
Routes of
Topical, by mouth
External links
AHFS/Drugs.comTopical: Monograph
ENT: Monograph
Legal status
  • UK: GSL, P
  • US: OTC
Chemical and physical data
Molar mass165.192 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 checkY

Benzocaine, sold under the brand name Orajel amongst others, is a local anesthetic.[2][3] Applied to the skin it may be used to help with minor skin injury, hemorrhoids, and premature ejaculation.[2] It may also be used mouth or ear pain.[3] Use in not recommended in those under 2 years old.[3]

While generally well tolerated, contact dermatitis may occur.[2] Other side effects may include methemoglobinemia, seizures, and respiratory depression.[2] Safety in pregnancy is unclear.[4] Use by the mom when breastfeeding is unlikely to be harmful.[5] It is an ester.[1]

Benzocaine was first made in 1890 in Germany and approved for medical use in 1902.[6] It is available as a generic medication and over the counter.[2][3] It is commonly used used many brand names.[1][3] In the United States a tube of 28 grams of 20% costs about 7 USD as of 2022.[7]

Medical uses

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

  • Local anesthesia of sore throat, cold sores, mouth ulcers, toothache, sore gums, denture irritation[8]
  • Earache[8]
  • Surgical or procedural local anesthesia[9]

Other uses

Jiffy Toothache Drops bottle (7.75% Benzocaine)

Benzocaine is used as a key ingredient in numerous pharmaceuticals:

  • Some glycerol-based ear medications for use in removing excess wax as well as relieving ear conditions such as otitis media and swimmers ear.
  • Some previous diet products such as Ayds.
  • Some condoms designed to prevent premature ejaculation. Benzocaine largely inhibits sensitivity on the penis, and can allow for an erection to be maintained longer (in a continuous act) by delaying ejaculation. Conversely, an erection will also fade faster if stimulus is interrupted.[10][11]
  • Benzocaine mucoadhesive patches have been used in reducing orthodontic pain.[12]
  • In Poland it is included, together with menthol and zinc oxide, in the liquid powder (not to be confused with the liquid face powder) used mainly after mosquito bites. Today's ready made Pudroderm[13] was once used there as pharmaceutical compound.

Available forms

Benzocaine can come in a variety of preparations including:

Oral preparations:

  • Lozenges (ex. Cepacol, Mycinettes)[14]
  • Throat Spray (ex. Ultra Chloraseptic)[15]

Topical preparations:

  • Aerosol (ex. Topex)[16]
  • Gel (ex. Orajel)[17]
  • Paste (ex. Orabase)[18]
  • Cream (ex. Lanacane - active ingredient 3% Benzocaine)

Otic preparations:

  • Solution (ex. Allergen)

It is also combined with antipyrine to form antipyrine and benzocaine ear drops to relieve ear pain.

Side effects

Benzocaine is generally well tolerated and non-toxic when applied topically as recommended.[19]

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.[20]

Overapplication of oral anesthetics such as benzocaine can increase the risk of pulmonary aspiration by relaxing the gag-reflex and allowing regurgitated stomach contents or oral secretions to enter the airway.[medical citation needed] Applying an oral anesthetic and consuming beverages before going to bed can be particularly hazardous.[medical citation needed]

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.[21] This side effect is most common in children under two years of age.[22] As a result, the FDA has stated that benzocaine products should not be used in children under two years of age, unless directed by and supervised by a healthcare professional.[23] In European countries, the contraindication applies to children under 12 years of age. Symptoms of methemoglobinemia usually occur within minutes to hours of applying benzocaine, and can occur upon the first-time use or after additional use.[23]

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



Pain is caused by the stimulation of free nerve endings. When the nerve endings are stimulated, sodium enters the neuron, causing depolarization of the nerve and subsequent initiation of an action potential. The action potential is propagated down the nerve toward the central nervous system, which interprets this as pain. Benzocaine acts to inhibit the voltage-dependent sodium channels (VDSCs) on the neuron membrane, stopping the propagation of the action potential.


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 88–90 °C,[30] and the boiling point is about 310 °C.[31] The density of benzocaine is 1.17 g/cm3.

Benzocaine is commonly found, particularly in Britain, as an additive in street cocaine and also as a bulking agent in "legal highs".[32] Whilst giving a numbing effect similar to cocaine, users prefer Benzocaine as it is a better bulking and binding agent that can't be detected once mixed. Benzocaine is the most popular cutting agent worldwide,[33] Benzocaine was used in synthesis of leteprinim. Treatment of benzocaine with hydrazine leads to aminostimil - a compound related to isoniazid.


Benzocaine can be prepared by esterification using 4-aminobenzoic acid and ethanol.[34][35] It can also be prepared by reduction of ethyl 4-nitrobenzoate to the amine.[36][37] In industrial practice, the reducing agent is usually iron and water in the presence of a little acid.[38]


Benzocaine was first synthesized in 1890 by the German chemist Eduard Ritsert (1859–1946),[39] in the town of Eberbach[40] and introduced to the market in 1902 under the name "Anästhesin".[41][42]

Other animals

A bath solution of benzocaine has been used to anesthetize amphibians for surgery.[43][44]


  1. 1.0 1.1 1.2 McFadden, John; Puangpet, Pailin; Pongpairoj, Korbkarn; Thaiwat, Supitchaya; Lee, Shan Xian (January 21, 2020). Common Contact Allergens: A Practical Guide to Detecting Contact Dermatitis. John Wiley & Sons. p. 297. ISBN 978-1-119-40566-5. Archived from the original on January 11, 2022. Retrieved January 9, 2022.
  2. 2.0 2.1 2.2 2.3 2.4 2.5 2.6 "Benzocaine (Topical) Monograph for Professionals". Archived from the original on March 4, 2021. Retrieved January 9, 2022.
  3. 3.0 3.1 3.2 3.3 3.4 3.5 "Benzocaine (EENT) Monograph for Professionals". Archived from the original on April 17, 2021. Retrieved January 9, 2022.
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  19. Lexicomp Online, Adult and Pediatric Lexi-Drugs Online, Hudson, Ohio: Lexi-Comp, Inc.; 2013; April 15, 2013.
  20. Food and Drug Administration. FDA Public Health Advisory: Life-threatening side effects with use of skin products containing numbing ingredients for cosmetic procedures. 2007 Feb 6, updated 2007 Feb 9. From FDA website
  21. Shua-Haim, J. R.; Gross, J. S. (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.
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  35. Erlenmeyer, E.; Wanklyn, J. A. (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. doi:10.1002/jlac.18651350202. Archived from the original on April 26, 2021. Retrieved May 26, 2021.
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  39. Biography of Eduard Ritsert (in German): Deutsche Biographie: Ritsert, Eduard. Archived June 8, 2019, at the Wayback Machine
  40. "100 years of Dr. Ritsert". Dr. Ritsert Pharma. Archived from the original on September 9, 2017. Retrieved March 14, 2010.
  41. Harry Auterhoff, Lehrbuch der pharmazeutischen Chemie (Stuttgart, Germany: Wissenschaftliche Verlagsgesellschaft, 1968).
  42. Ritsert, E. (1925) "Über den Werdegang des Anästhesins" (On the development of Anästhesin), Pharmazeutische Zeitung, vol. 60, pages 1006–1008. See also: Christoph Friedrich and Magdalena Klimonow, "150. Geburtstag: Eduard Ritsert und das Anaesthesin" Archived March 20, 2014, at the Wayback Machine (150th birthday: Eduard Ritsert and Anästhetsin [Benzocaine]"), Pharmazeutische Zeitung online. First published clinical study demonstrating the efficacy of benzocaine: Noorden, C. v. (1902) "Ueber para-Aminobenzoesäure-Ester als locales Anästhetikum" (On [an] ester of para-aminobenzoic acid as a local anaesthetic), Klinische Wochenschrift, vol. 39, pages 373–375.
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External links

External sites: