Review Prilocaine spinal anesthesia for ambulatory surgery: A review of the available studies § Jan Boublik a , Ruchir Gupta b , Supurna Bhar c , Arthur Atchabahian d, * a Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA, USA b Department of Anesthesiology, Stony Brook School of Medicine, Stony Brook, NY, USA c Long Island University School of Pharmacy, Brooklyn, NY, USA d Department of Anesthesiology, NYU School of Medicine, 301 East 17th Street, Rm C2-222, 10003 New York, NY, USA 1. Introduction Spinal anesthesia is a safe and reliable anesthetic modality for surgical procedures on the lower part of the body. However, because of the description of transient neurologic symptoms (TNS) following lidocaine spinal [1] with an incidence of 10% to 40% [2–5], most practitioners have abandoned the use of lidocaine for that purpose. Suggested replacements have included mepiv- acaine (with an incidence of TNS of up to 30% [6,7]), low-dose bupivacaine (extremely variable in the duration of the block [8]), procaine (which in one study resulted in a 15% rate of nausea, 15% failed blocks, and TNS in 6% of the cases) [9], articaine [10], 2- chloroprocaine [11] and prilocaine. The last two medications were recently approved for intrathecal use in Europe. The purpose of this article is to review the available data on the use of prilocaine for spinal anesthesia and to better define its role in the armamentarium of intrathecal medications. Given the limited amount of data, we did not undertake a formal systematic review. 2. Historical background Prilocaine is an amide local anesthetic that has been used for over five decades for spinal anesthesia. In the liver, prilocaine is primarily metabolized by amide hydrolysis to s-toluidine and N-propylalanine; s-toluidine is subsequently hydroxylated to 2-amino-3-hydroxytoluene and 2-amino 5-hydroxytoluene, metabolites responsible for the occurrence of methaemoglobine- mia [12]. A high dose of prilocaine (more than 6 mg/kg) is needed to cause a clinically apparent methaemoglobinemia in the healthy adult [13]. It was first introduced around 1960 and has been used for infiltration, peripheral nerve block, and epidural anesthesia. Initially, it gathered momentum slowly as a spinal anesthetic agent partially because of the popularity of lidocaine. Prilocaine is a remarkably short-acting drug and is associated with far fewer reported cases of transient neurological symptoms than lidocaine or mepivacaine [14]. A hyperbaric formulation of 5% prilocaine was used as standard medication for spinal anesthesia in England until 1978 and in France until 1998. The drug was then withdrawn from the market for commercial reasons and because of the poor Anaesth Crit Care Pain Med xxx (2016) xxx–xxx A R T I C L E I N F O Article history: Available online xxx Keywords: Prilocaine Intrathecal Spinal Ambulatory surgery Transient neurological syndrome Urinary retention A B S T R A C T Transient neurologic symptoms (TNS) led to the abandonment of intrathecal lidocaine. We reviewed the published literature for information about the duration of action and side effects of intrathecal prilocaine, which has been recently reintroduced in Europe. Medline and EMBASE databases were searched for the time period from 1966 to 2015. Fourteen prospective and one retrospective study were retrieved. The duration of the surgical block can be adjusted using doses between 40 and 80 mg. Hyperbaric prilocaine in doses as low as 10 mg can be used for perianal procedures. Four cases of TNS in 486 patients were reported in prospective studies, and none in 5000 cases in a retrospective data set. Spinal prilocaine appears to be safe and reliable for day case anesthesia. However, as chloroprocaine has a shorter duration and a lower risk of TNS and urinary retention, the indications for prilocaine remain to be defined. ß 2016 Socie ´ te ´ franc ¸aise d’anesthe ´ sie et de re ´ animation (Sfar). Published by Elsevier Masson SAS. All rights reserved. § Presented in part at the American Society of Regional Anesthesia and Pain Medicine, 39th Annual Regional Anesthesia Meeting April 3–6 2014 in Chicago, Illinois, United States of America. * Corresponding author. Tel.: +1212 598 6085; fax: +1212 598 6163. E-mail addresses: jan.boublik@gmail.com (J. Boublik), guptar2005@yahoo.com (R. Gupta), supurna_bhar@yahoo.com (S. Bhar), arthur.atchabahian@gmail.com (A. Atchabahian). G Model ACCPM-149; No. of Pages 5 Please cite this article in press as: Boublik J, et al. Prilocaine spinal anesthesia for ambulatory surgery: A review of the available studies. Anaesth Crit Care Pain Med (2016), http://dx.doi.org/10.1016/j.accpm.2016.03.005 http://dx.doi.org/10.1016/j.accpm.2016.03.005 2352-5568/ß 2016 Socie ´te ´ franc ¸aise d’anesthe ´ sie et de re ´ animation (Sfar). Published by Elsevier Masson SAS. All rights reserved.