Benzocaine
530862
223442961
2008-07-04T02:42:31Z
LordRM
94925
{{drugbox
| IUPAC_name = ethyl 4-aminobenzoate
| image = Benzocaine.svg
| CAS_number = 94-09-7
| ATC_prefix = C05
| ATC_suffix = AD03
| ATC_supplemental = {{ATC|D04|AB04}}, {{ATC|N01|BA05}}, {{ATC|R02|AD01}}
| PubChem = 2337
| DrugBank = APRD00539
| C=9 | H=11 | N=1 | O=2
| molecular_weight = 165.189 g/mol
| bioavailability =
| protein_bound =
| metabolism =
| elimination_half-life =
| pregnancy_category = C (USA)
| legal_status =''' | routes_of_administration = topical
}}'''Benzocaine''' is a [[local anesthetic]] commonly used as a [[topical]] pain reliever. It is the active ingredient in many over-the-counter [[anesthetic]] ointments (e.g. products for [[oral ulcer]]s of Anbesol by [[Wyeth]], Kank+a by [[Blistex]], Orabase B and Orajel by Del Pharmaceuticals).
==Chemical properties==
Benzocaine is an [[ester]], and can be prepared from the organic acid [[para-Aminobenzoic acid|PABA]] (para-aminobenzoic acid) and [[ethanol]] by [[Fischer esterification]]. The melting point of benzocaine is 88-90 degrees Celsius, and the boiling point is 310 degrees Celsius. The density of benzocaine is 1.17 g/cm<sup>3</sup>.
==History==
Benzocaine was first synthesised by a German chemical firm named Ritsert, in the town of [[Eberbach (Baden)|Eberbach]].
==How it relieves pain==
Pain is caused by the stimulation of [[free nerve ending]]s. When the nerve endings are stimulated, sodium enters the [[neuron]], which causes an electrical potential to build up in the nerve. Once the electrical potential becomes big enough the signal is propagated down the nerve toward the [[central nervous system]], which interprets this as pain.
[[Ester]]s of [[para-Aminobenzoic acid|PABA]] work as a chemical barrier, stopping the sodium from being able to enter the nerve ending.
==Side effects==
Allergic reactions occur with ester local anaesthetics (like benzocaine) because of the PABA structure.
Benzocaine also is a well-known cause of [[methemoglobinemia]]. Because it may be used in topical creams with a concentration as much as 20%, it is not difficult to administer a dose sufficient to cause this problem.
==Other uses==
Benzocaine can also be used as a fish tranquilizer. Due to its low solubility in water, stock solution can be made with [[ethanol]] (95%). 25 g of benzocaine per 200 ml ethanol will make a solution strong enough to knock saltwater fish out in 2-4 minutes. They will regain equilibrium after 10-15 minutes. Use 5 ml stock solution per 1 L of saltwater. Some benzocaine will [[precipitate]] out of solution when added to the saltwater, so it is recommended to add the volume of stock solution you will be using to a separate container and mix it with some saltwater before adding it to the tank.{{Fact|date=May 2008}}
Benzocaine is also used as a key ingredient in Phenazone, an anti-inflammatory, and is also used in some glycerol-based ear medications for use in removing excess wax as well as ear conditions such as [[Otitis media|Otitis Media]] and [[Otitis externa|swimmers ear]].
It is also used in certain condoms to prolong sex by numbing the penis.<ref>[http://archives.cnn.com/2002/HEALTH/10/17/condom 'Delay' condom proves popular - CNN.com]</ref> It also can be sprayed in the back of the throat to numb the gag reflex during fellatio.
Benzocaine is an ingredient in some [[anal sex]] lubricants <ref>[http://www.a-womans-touch.com/article/11/413/Things_you_wont_find_on_our_website.html AWT: Things you won't find on our website - Product Guides | A Woman's Touch - A comfortable place to celebrate your healthy sexual self. Madison & Milwaukee, WI<!-- Bot generated title -->]</ref> to provide temporary relief to the discomforts of anal sex. It temporarily numbs the [[sphincter muscle]] for about 10 to 15 minutes.
Benzocaine used to be used as an appetite suppressant in diet products such as [[Ayds]].
==Misconceptions==
In Phillip K. Dick's book [[A Scanner Darkly]], one of the main characters attempts to extract pure cocaine out of a bottle of sunburn spray by freezing it, claiming that Benzocaine is simply an industry name for [[Cocaine]], of course this is not true.
==References==
<references/>
==External links==
* [http://www.fda.gov/CDER/drug/advisory/benzocaine.htm FDA investigation of the possible adverse effects of benzocaine mouth and throat sprays.]
* [http://www.orajel.com/ Orajel.com] - official website
* [http://msds.chem.ox.ac.uk/BE/benzocaine.html Safety data] from the Chemistry Department at Oxford University.
{{Vasoprotectives}}
{{Antipruritics}}
{{Local anesthetics}}
{{Throat preparations}}
[[Category:Local anesthetics]]
[[Category:Benzoates]]
[[de:Benzocain]]
[[es:Benzocaína]]
[[fr:Benzocaïne]]
[[it:Benzocaina]]
[[he:בנזוקאין]]
[[hu:Benzokain]]
[[nl:Benzocaïne]]
[[pl:Benzokaina]]
[[pt:Benzocaína]]