RESEARCH MONOGRAPH · KDC-MN-1314
Procaine
Procaine is the original synthetic local anesthetic, synthesized in 1905 by Alfred Einhorn and marketed by Hoechst as Novocain. It was developed as a non-addictive cocaine substitute and dominated the field from 1905 through the 1950s before lidocaine and the amide class displaced it owing to faster onset, longer duration, and far fewer allergic reactions. The ester-class downside: hydrolysis by plasma cholinesterase produces para-aminobenzoic acid (PABA), the dominant allergen in the class. Plasma half-life of procaine itself is under one minute; clinical infiltration block lasts only 30 to 60 minutes. Modern use is essentially restricted to short-procedure infiltration in patients with documented amide allergy and to a few dental applications. Procaine penicillin (the depot antibiotic formulation) is the oldest application of procaine in pharmaceutical formulation and is the principal reason most clinicians have heard of it. Not stocked by Kodiac. This monograph is provided for research and educational reference.
Intrigue 0–100 blends mechanism novelty, evidence strength, and translational potential. Kodiac editorial, not peer-reviewed.
Ester local anesthetic (short-acting)
The original synthetic local anesthetic introduced in 1905 as Novocaine, displaced by amide agents but retaining historical and reference status.
Abstract
Procaine (2-(diethylamino)ethyl 4-aminobenzoate; CAS 59-46-1; molecular formula C13H20N2O2; molecular weight 236.31) is the original synthetic local anesthetic, synthesized by Alfred Einhorn at the University of Munich in 1905 and marketed by Hoechst as Novocain. The compound was developed as a cocaine substitute that lacked the abuse liability and addictive potential of the natural alkaloid; the ester linkage between the aromatic ring and the amino alcohol substantially reduces lipophilicity relative to cocaine while preserving sodium channel block. Procaine was the dominant local anesthetic from 1905 through approximately the 1950s, when lidocaine and the amide class displaced it owing to faster onset, longer duration, and substantially lower allergic reaction incidence. The principal limitation of procaine and the ester class is hydrolysis by plasma cholinesterase to para-aminobenzoic acid (PABA), the dominant allergen in the class and a substrate for hapten-mediated immune reactions in sensitized individuals. The plasma half-life is short (less than 1 minute through cholinesterase clearance); duration of clinical infiltration block is 30 to 60 minutes, much shorter than amide agents. Mechanism is voltage-gated sodium channel block with state-dependent kinetics; the lower lipid solubility relative to amide agents corresponds to slower onset and weaker block per milligram. Modern clinical use is limited to short-procedure infiltration in patients with documented amide allergy and to several dental applications in markets where the ester formulations remain available. Procaine penicillin (combined with penicillin G as a depot) extends antibiotic plasma levels and is the oldest application of procaine in formulation.
Mechanism of action
Voltage-gated sodium channel block, state-dependent, lower potency than amide class. Hydrolyzed by plasma cholinesterase to PABA (the dominant allergen).
Reported research dose ranges
Reported research dose ranges vary across the published literature.
References
- Einhorn A. On the chemistry of local anesthetics. Munch Med Wochenschr 1905.
- Covino BG. Pharmacology of local anaesthetic agents. Br J Anaesth 1986.
Read the full monograph
Available as a research-use-only PDF download.
The full reference document is provided strictly for research use only. It reports research dose ranges from the published literature, not instructions for use in humans or animals.
FOR RESEARCH USE ONLY. Not for medical, diagnostic, or therapeutic purposes. Not for human consumption. All information is provided for research and educational purposes only.