Benzocaine

Benzocaine

Clinical data
Trade names	Anbesol, Cepacol, Lanacane, Orajel
AHFS/Drugs.com	Monograph
Pregnancy category	US: C (Risk not ruled out)
Routes of administration	Topical
ATC code	C05AD03 (WHO) D04AB04 (WHO), QN01AX92 (WHO), N01BA05 (WHO), R02AD01 (WHO)
Legal status
Legal status	UK: General sales list (GSL, OTC) US: OTC
Identifiers
IUPAC name Ethyl 4-aminobenzoate
CAS Number	94-09-7 Y
PubChem CID	2337
DrugBank	DB01086 Y
ChemSpider	13854242 Y
UNII	U3RSY48JW5
KEGG	D00552 Y
ChEBI	CHEBI:116735 Y
ChEMBL	CHEMBL278172 Y
ECHA InfoCard	100.002.094
Chemical and physical data
Formula	C9H11NO2
Molar mass	165.189 g/mol
3D model (Jmol)	Interactive image
SMILES O=C(OCC)c1ccc(N)cc1
InChI InChI=1S/C9H11NO2/c1-2-12-9(11)7-3-5-8(10)6-4-7/h3-6H,2,10H2,1H3 Y Key:BLFLLBZGZJTVJG-UHFFFAOYSA-N Y

Benzocaine is a local anesthetic commonly used as a topical pain reliever or in cough drops. It is the active ingredient in many over-the-counter anesthetic ointments such as products for oral ulcers. It is also combined with antipyrine to form A/B otic drops to relieve ear pain and remove earwax.

Benzocaine is the ethyl ester of p-aminobenzoic acid (PABA). It can be prepared from PABA and ethanol 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, and the boiling point is about 310 °C. The density of benzocaine is 1.17 g/cm³.

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

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.