Benzocaine

Benzocaine is a local anesthetic commonly used as a topical pain reliever. It is the active ingredient in many over-the-counter analgesic ointments. more...

Chemical properties

Benzocaine is an ester, a compound made from the organic acid PABA (para-aminobenzoic acid) and ethanol. The process in which this ester is created is known as Fischer esterification.

How it relieves pain

Pain is caused by the stimulation of nerve endings. When the nerve endings are stimulated, sodium enters the nerve ending, which causes an electrical signal to build up in the nerve. Once the electrical signal becomes big enough, it is able to travel to the brain, which then interprets this as pain.

Esters of PABA work as a chemical barrier, stopping the sodium from being able to enter the nerve ending.

Related products

There are various other products that are also made from esters of PABA, many of which have similar anaesthetic properties. Dentists use Procaine (also called Novocaine) to numb teeth and gums.

Benzocaine is also contained in products such as:

• First aid creams
• Sore-throat spray
• Sunburn remedies
• Condoms (to prevent premature ejaculation)

Other Uses

Benzocaine can also be used as a fish anesthetic. Due to its low solubility in water stock solution can be made with ethanol (95%). 25g of benzocaine per 200ml 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 5ml stock solution per 1L 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.

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