Correspondence  |   April 2009
Until Proven Otherwise, 5% Spinal Procaine Is Not Neurotoxic
Author Affiliations & Notes
  • Mark S. Shulman, M.D.
  • *Caritas St. Elizabeth's Medical Center, Boston, Massachusetts.
Article Information
Correspondence   |   April 2009
Until Proven Otherwise, 5% Spinal Procaine Is Not Neurotoxic
Anesthesiology 4 2009, Vol.110, 946. doi:10.1097/ALN.0b013e31819b6403
Anesthesiology 4 2009, Vol.110, 946. doi:10.1097/ALN.0b013e31819b6403
To the Editor:—
We read with interest the article by Johnson and Swanson on procaine neurotoxicity,1 and are interested in why they decided to use undiluted 10% procaine instead of 5% procaine prepared with 10% procaine and equal volumes of either 10% glucose or cerebral spinal fluid.
When the first report of transient radicular irritation with spinal anesthesia using 5% lidocaine appeared,2 our department decided to change to the routine use of 10% procaine for spinal anesthesia. We decided to use a 5% concentration as advocated by Winnie in his use of procaine for differential spinals in 1978.3 The statement that recent anesthesia texts do not recommend using a maximum concentration of 5% procaine is incorrect. Two anesthesia texts from our library either stated that spinal procaine should not be injected in concentrations exceeding 5%,4 or that spinal procaine in a strength of 5% or less is not irritating to nervous tissue and meninges.5 The recommendation to use 5% procaine is not referenced in these texts, but may have come from papers published in the 1930s that described neurotoxicity with 10% spinal procaine.6,7 It is true that there are no current studies available describing the neurotoxicity of spinal procaine,8 although it has been stated that “local anesthetics all have the potential to be neurotoxic particularly in concentrations and doses larger than those used clinically.”8 It appears that 10% spinal procaine may have that potential and should not be used for spinal anesthesia.
We still feel that 5% spinal procaine remains a viable alternative to lidocaine, because there is no evidence at present that it is neurotoxic.
*Caritas St. Elizabeth's Medical Center, Boston, Massachusetts.
Johnson ME, Swanson JW: Procaine spinal neurotoxicity. Anesthesiology 2008; 109:349–51Johnson, ME Swanson, JW
Schneider M, Ettlin T, Kaufmann M, Schumacher P, Urwyler A, Hampl K, von Hochstetter A: Transient neurologic toxicity after hyperbaric subarachnoid anesthesia with 5% lidocaine. Anesth Analg 1993; 76:1154–7Schneider, M Ettlin, T Kaufmann, M Schumacher, P Urwyler, A Hampl, K von Hochstetter, A
Winnie AP: Differential diagnosis of pain mechanisms. ASA Refresher Courses in Anesthesiology. Philadelphia, JB Lippincott Company, 1978; pp 171–86Winnie, AP Philadelphia JB Lippincott Company
Cousins MJ, Bridenbaugh PO: Neural blockade in clinical anesthesia and management of pain, 3rd edition. Philadelphia, Lippincott-Raven Publishers, 1998; p 213Cousins, MJ Bridenbaugh, PO Philadelphia Lippincott-Raven Publishers
Atkinson RS, Rushman GB, Lee JA: A Synopsis of Anesthesia, 10th edition. Wright Publishers, Bristol, 1987; p 678Atkinson, RS Rushman, GB Lee, JA Wright Publishers Bristol
Ferguson FR, Watkins KH: Paralysis of the bladder and associated neurological sequelae of spinal anesthesia (cauda equina syndrome). Br J Surg 1938; 25:735–52Ferguson, FR Watkins, KH
MacDonald AD, Watkins KH: An experimental investigation into the cause of paralysis following spinal anesthesia. Br J Surg 1938; 25:879–83MacDonald, AD Watkins, KH
Hodgson PS, Neal JM, Pollock JE, Liu SS: The neurotoxicity of drugs given intrathecally (spinal). Anesth Analg 1999; 88:797–809Hodgson, PS Neal, JM Pollock, JE Liu, SS