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.[9][10]
Benzocaine mucoadhesive patches have been used in reducing orthodontic pain.[11]
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[12] was once used there as pharmaceutical compound.
Available forms
Benzocaine can come in a variety of preparations including:
Cream (ex. Lanacane - active ingredient 3% Benzocaine)
Otic preparations:
Solution (ex. Allergen)
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:
Benzocaine is commonly found, particularly in Britain, as an additive in street cocaine and also as a bulking agent in "legal highs".[32] 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.[33]
Treatment of benzocaine with hydrazine leads to aminostimil, a compound related to isoniazid.
Synthesis
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]
History
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]
Veterinary medicine
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]
^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. PMID23301559. S2CID22561192.
^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. PMID10357712.
^ abCetylite Industries. Cetacaine (benzocaine 14%, tetracaine 2% and butamben 2%) spray, gel and liquid prescribing information. Pennsauken, NJ; 2006 Sept.
^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.
^"Benzocaine". PubChem. U.S. National Library of Medicine. Retrieved March 27, 2023.
^D'Ans-Lax, Taschenbuch für Chemiker und Physiker. Organische Verbindungen (4th ed.). Berlin: Springer Verlag. 1983. ISBN3-540-12263-X.
^Auterhoff H (1968). Lehrbuch der pharmazeutischen Chemie. Stuttgart, Germany: Wissenschaftliche Verlagsgesellschaft.
^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.
