RESEARCH MONOGRAPH · KDC-MN-1319
Chloroprocaine
Chloroprocaine (Nesacaine) is a 2-chloro analog of procaine introduced in the 1950s. The single chlorine substitution adjacent to the ester linkage dramatically accelerates plasma cholinesterase hydrolysis, producing the shortest plasma half-life of any clinical local anesthetic (roughly 21 seconds). That ultra-short systemic exposure makes chloroprocaine the safest local anesthetic for fetal exposure during obstetric epidural, and a useful agent for short-procedure spinal anesthesia in ambulatory surgical centers. The historical association with cauda equina syndrome traced to a sodium bisulfite preservative, not the drug itself; reformulation with EDTA and later preservative-free preparations resolved that concern, and chloroprocaine has returned to ambulatory spinal anesthesia as an alternative to lidocaine spinal (which carries its own transient neurologic symptoms concern). 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 Kodiac editorial, not peer-reviewed.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 (very short-acting)
A 2-chloro-substituted procaine analog with the fastest plasma cholinesterase hydrolysis among local anesthetics, used in obstetric epidural and short-procedure spinal anesthesia.
Abstract
Chloroprocaine (2-(diethylamino)ethyl 4-amino-2-chlorobenzoate; CAS 133-16-4; molecular formula C13H19ClN2O2; molecular weight 270.76) is an ester-class local anesthetic introduced in the 1950s (Nesacaine) as a 2-chloro analog of procaine. The 2-chloro substitution adjacent to the ester linkage substantially accelerates plasma cholinesterase hydrolysis, producing the shortest plasma half-life of any clinical local anesthetic (approximately 21 seconds, versus 1 minute for procaine and far longer for amides). The very short systemic exposure makes chloroprocaine the safest local anesthetic for fetal exposure during obstetric epidural anesthesia and a useful agent for short-procedure spinal anesthesia in ambulatory surgical centers where rapid offset and discharge readiness are operationally valuable. Mechanism is voltage-gated sodium channel block with state-dependent kinetics; potency is similar to procaine on a milligram basis and substantially less than amide agents. The historical association with neurotoxicity (cauda equina syndrome) traces to the bisulfite preservative formulation used in Nesacaine through the 1980s and a high-pH, sodium bisulfite preservative system that produced free radical injury to nerve roots when administered intrathecally; reformulation with EDTA preservative and subsequent preservative-free 1 percent and 3 percent preparations resolved the neurotoxicity concern, and chloroprocaine has returned to spinal anesthesia use in ambulatory surgery as an alternative to lidocaine spinal (which carries its own transient neurologic symptoms concern). Modern formulations are preservative-free or use methylparaben preservatives at concentrations below the historical threshold for nerve injury.
Mechanism of action
Voltage-gated sodium channel block. Very rapid plasma cholinesterase hydrolysis (half-life ~21 seconds).
Reported research dose ranges
Reported research dose ranges vary across the published literature.
References
- Smith KN, et al. Spinal 2-chloroprocaine: a comparison with small-dose bupivacaine. Anesthesiology 2004.
- Reisner LS, et al. Persistent neurologic deficit after intrathecal 2-chloroprocaine. Anesth Analg 1980.
- Goldblum E, Atchabahian A. The use of 2-chloroprocaine for spinal anaesthesia. Acta Anaesthesiol Scand 2013.
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.