Procaine hydrochloride is a local anesthetic used primarily in dentistry. It is primarily known as novocaine, or by the trade name "Novocain".
Procaine was first synthesized in 1905, and was the first injectable man-made local anesthetic used. It was created by the German chemist Alfred Einhorn who gave the chemical the trade name Novocaine, from the Latin 'Novus' (meaning New) plus 'caine' as in "cocaine". It was introduced into medical use by surgeon Heinrich Braun. The proper chemical name for procaine is 2-Diethylaminoethyl 4-aminobenzoate hydrochloride and the chemical formula is C13H20N2O2·HCl.
Procaine is rarely used today since more effective alternatives such as lidocaine (xylocaine) exist. Prior to the discover of procaine, cocaine was the most commonly used local anesthetic. Procaine has the advantage of restricted blood vessels, unlike other local anesthetics like cocaine, which reduces bleeding. It is also less toxic than cocaine.
Procaine, an ester anesthetic, is metabolized in the plasma by the enzyme pseudocholinesterase through hydrolysis into para-aminobenzoic acid (PABA), which is then excreted by the kidneys into the urine. Allergic reactions to procaine are usually not in response to procaine itself, but to PABA. About 1 in 3000 people have an atypical form of pseudocholinesterase, which doesn't hydrolyze ester anesthetics such as procaine, resulting in a prolonged period of high levels of the anesthetic in the blood and increased toxicity.
