Systematic (IUPAC) name
Clinical data
Trade names Xylocaine
AHFS/ Micromedex Detailed Consumer Information
  • AU: A
  • US: B (No risk in non-human studies)
intravenous, subcutaneous, topical, oral
Pharmacokinetic data
Bioavailability 35% (oral)
3% (topical)
Metabolism Hepatic, 90% CYP1A2-mediated
Half-life 1.5–2 hours
Excretion renal
137-58-6 7pxY
73-78-9 (hydrochloride)
C01BB01 C05AD01 D04AB01 N01BB02 R02AD02 S01HA07 S02DA01
PubChem CID 367
IUPHAR ligand 2623
DrugBank DB00281 7pxY
ChemSpider 3548 7pxY
UNII 98PI200987 7pxY
KEGG D00358 7pxY
ChEBI CHEBI:6456 7pxY
Synonyms N-(2,6-dimethylphenyl)-N2,N2-diethylglycinamide
Chemical data
Formula C14H22N2O
234.34 g/mol
Physical data
Melting point Script error: No such module "convert".
 14pxY (what is this?)  (verify)

Lidocaine (INN, BAN) /ˈldɵkn/, xylocaine, or lignocaine (AAN, former BAN) /ˈlɪɡnɵkn/ is a common local anesthetic and class-1b antiarrhythmic drug. Lidocaine is used topically to relieve itching, burning, and pain from skin inflammations, injected as a dental anesthetic, or used as a local anesthetic for minor surgery.

It is on the WHO Model List of Essential Medicines, the most important medications needed in a basic healthcare system.[1]

Medical uses

The efficacy profile of lidocaine as a local anesthetic is characterized by a rapid onset of action and intermediate duration of efficacy. Therefore, lidocaine is suitable for infiltration, block, and surface anesthesia. Longer-acting substances such as bupivacaine are sometimes given preference for subdural and epidural anesthesias; lidocaine, though, has the advantage of a rapid onset of action. Epinephrine (adrenaline) vasoconstricts arteries, reducing bleeding and also delays the resorption of lidocaine, almost doubling the duration of anaesthesia. For surface anesthesia, several available formulations can be used for endoscopies, before intubations, etc. Buffering the pH of lidocaine makes local freezing less painful.[2] Lidocaine drops can be used on the eyes for short ophthalmic procedures.

There is tentative evidence for topical lidocaine for neuropathic pain.[3] Intravenous lidocaine also has uses as a temporary fix for tinnitus. Although not completely curing the disorder, it has been shown to reduce the effects by around two-thirds.[4][5]

Lidocaine is also the most important class-1b antiarrhythmic drug; it is used intravenously for the treatment of ventricular arrhythmias (for acute myocardial infarction, digoxin poisoning, cardioversion, or cardiac catheterization) if amiodarone is not available or contraindicated. Lidocaine should be given for this indication after defibrillation, CPR, and vasopressors have been initiated. A routine prophylactic administration is no longer recommended for acute cardiac infarction; the overall benefit of this measure is not convincing.

Inhaled lidocaine can be used as an antitussive (cough suppressor) acting peripherally to reduce the cough reflex. This application can be implemented as a safety and comfort measure for patients who have to be intubated, as it reduces the incidence of coughing and any tracheal damage it might cause when emerging from anesthesia.[6][7][8]

Lidocaine, along with ethanol, ammonia, and acetic acid, has also been proven to be effective in treating jellyfish stings, both numbing the affected area and preventing further nematocyst discharge.[9][10]


Relative insensitivity to lidocaine is genetic. In hypokalemic sensory overstimulation, relative insensitivity to lidocaine has been described in people who also have attention deficit hyperactivity disorder.[11] In dental anesthesia, a relative insensitivity to lidocaine can occur for anatomical reasons due to unexpected positions of nerves. Some people with Ehlers-Danlos syndrome are insensitive to lidocaine.[12]


Absolute contraindications for the use of lidocaine include:

Exercise caution in patients with any of these:

  • Hypotension not due to arrhythmia
  • Bradycardia
  • Accelerated idioventricular rhythm
  • Elderly patients
  • Pseudocholinesterase deficiency
  • Intra-articular infusion (this is not an approved indication and can cause chondrolysis)
  • Porphyria, especially acute intermittent porphyria; lidocaine has been classified as porphyrogenic because of the hepatic enzymes it induces,[15] although clinical evidence suggests it is not.[16] Bupivacaine is a safe alternative in this case.
  • Impaired liver function - people with lowered hepatic function may have an adverse reaction with repeated administration of lidocaine because the drug is metabolized by the liver. Adverse reactions may include neurological symptoms (e.g. dizziness, nausea, muscle twitches, vomiting, or seizures).[17]

Adverse effects

Adverse drug reactions (ADRs) are rare when lidocaine is used as a local anesthetic and is administered correctly. Most ADRs associated with lidocaine for anesthesia relate to administration technique (resulting in systemic exposure) or pharmacological effects of anesthesia, and allergic reactions only rarely occur.[18] Systemic exposure to excessive quantities of lidocaine mainly result in central nervous system (CNS) and cardiovascular effects – CNS effects usually occur at lower blood plasma concentrations and additional cardiovascular effects present at higher concentrations, though cardiovascular collapse may also occur with low concentrations. ADRs by system are:

  • CNS excitation: nervousness, agitation, anxiety, apprehension, tingling around the mouth (circumoral paraesthesia), headache, hyperesthesia, tremor, dizziness, pupillary changes, psychosis, euphoria, hallucinations, and seizures
  • CNS depression with increasingly heavier exposure: drowsiness, lethargy, slurred speech, hypoesthesia, confusion, disorientation, loss of consciousness, respiratory depression and apnoea.
  • Cardiovascular: hypotension, bradycardia, arrhythmias, flushing, venous insufficiency, increased defibrillator threshold, edema, and/or cardiac arrest – some of which may be due to hypoxemia secondary to respiratory depression.[19]
  • Respiratory: Bronchospasm, dyspnea, respiratory depression or arrest
  • Gastrointestinal: metallic taste, nausea, vomiting
  • Ears: tinnitus
  • Eyes: local burning, Conjunctival hyperemia, corneal epithelial changes/ulceration, diplopia, visual changes (opacification)
  • Skin: itching, depigmentation, rash, urticaria, edema, angioedema, bruising, inflammation of the vein at the injection site, irritation of the skin when applied topically
  • Blood: methemoglobinemia
  • Allergy

ADRs associated with the use of intravenous lidocaine are similar to toxic effects from systemic exposure above. These are dose-related and more frequent at high infusion rates (≥3 mg/min). Common ADRs include: headache, dizziness, drowsiness, confusion, visual disturbances, tinnitus, tremor, and/or paraesthesia. Infrequent ADRs associated with the use of lidocaine include: hypotension, bradycardia, arrhythmias, cardiac arrest, muscle twitching, seizures, coma, and/or respiratory depression.[19]

It is generally safe to use lidocaine with vasoconstrictor such as epinephrine including in regions such as the nose, ears, fingers and toes.[20] While concerns of tissue death if used in these areas have been raised evidence does not support these concerns.[20]


Overdoses with lidocaine can be a result of excessive administration by topical or parenteral routes, accidental oral ingestion of topical preparations by children who are more susceptible to overdose, accidental intravenous (rather than subcutaneous, intrathecal, or paracervical) injection, or prolonged use of subcutaneous infiltration anesthesia during cosmetic surgical procedures. These occurrences have often led to severe toxicity or death in both children and adults. Lidocaine and its two major metabolites may be quantified in blood, plasma, or serum to confirm the diagnosis in potential poisoning victims or to assist in the forensic investigation in a case of fatal overdose. It is important in the interpretation of analytical results to recognize that lidocaine is often routinely administered intravenously as an antiarrhythmic agent in critical cardiac-care situations.[21] Treatment with intravenous lipid emulsions (used for parental feeding) to reverse the effects of local anaesthetic toxicity is becoming more commonplace.[22]


Any drugs that are also ligands of CYP3A4 and CYP1A2 can potentially increase serum levels and potential for toxicity or decrease serum levels and the efficacy, depending on whether they induce or inhibit the enzymes, respectively. Drugs that may increase the chance of methemoglobinemia should also be considered carefully. Dronedarone and liposomal morphine are both absolutely contraindicated, as they may increase the serum levels, but hundreds of other drugs require monitoring for interaction.[23]

Dosage forms

File:Lidocaine HCl local anesthetic cartridge.JPG
Lidocaine hydrochloride 2% epinephrine 1:80,000 solution for injection in a cartridge
File:Lidocaine hci.jpg
Lidocaine hydrochloride 1% solution for injection
File:Xylocaina spray.jpg
Topical lidocaine spray

Lidocaine, usually in the form of lidocaine hydrochloride, is available in various forms including:

  • Injected local anesthetic (sometimes combined with epinephrine to reduce bleeding)
  • Dermal patch (sometimes combined with prilocaine)
  • Intravenous injection
  • Intravenous infusion
  • Intraosseous infusion
  • Nasal instillation/spray (combined with phenylephrine)
  • Oral gel (often referred to as "viscous lidocaine" or abbreviated "lidocaine visc" or "lidocaine HCl visc" in pharmacology; used as teething gel)
  • Oral liquid
  • Oral and topical ointments, with and without flavoring, respectively[24][25]
  • Topical gel (as with aloe vera gels that include lidocaine)[26]
  • Topical liquid
  • Lidocaine HCl 2% jelly, combined with hypromellose, to anesthetize and lubricate the urethra, etc., for inserting a catheter or instrument
  • Topical patch (lidocaine 5%), marketed since 1999 in the US by Endo Pharmaceuticals[27] as "Lidoderm" - and since 2007 in the UK by Grünenthal as "Versatis".
  • Topical ointment (lidocaine 5%) as a temporary reliever of discomfort associated anorectal disorders, such as hemorrhoids, marketed as an over-the-counter product in the US as RectiCare since 2012 by Ferndale Healthcare, Inc
  • Topical aerosol spray
  • Inhaled by nebulizer
  • As a component of a GI cocktail used in emergency rooms
  • Ophthalmic solution

Adulterant in cocaine

Lidocaine is often added to cocaine as a diluent.[28] Cocaine numbs the gums when applied, and since lidocaine causes stronger numbness,[29] a user gets the impression of high-quality cocaine when in actuality, the user is receiving a diluted product.[30]


The onset of action of lidocaine is about 45 to 90 sec and its duration is 10 to 20 min. It is about 95% metabolized (dealkylated) in the liver mainly by CYP3A4 to the pharmacologically active metabolites monoethylglycinexylidide (MEGX) and then subsequently to the inactive glycine xylidide. MEGX has a longer half-life than lidocaine, but also is a less potent sodium channel blocker.[31] The volume of distribution is 1.1-2.1 l/kg, but congestive heart failure can decrease it. About 60-80% circulates bound to the protein alpha1 acid glycoprotein. The oral bioavailability is 35% and the topical bioavailability is 3%.

The elimination half-life of lidocaine is biphasic and around 90–120 min in most patients. This may be prolonged in patients with hepatic impairment (average 343 min) or congestive heart failure (average 136 min).[32] Lidocaine is excreted in the urine (90% as metabolites and 10% as unchanged drug).[33]



Lidocaine alters signal conduction in neurons by blocking the fast voltage-gated Na+ channels in the neuronal cell membrane responsible for signal propagation.[34] With sufficient blockage, the membrane of the postsynaptic neuron will not depolarize and will thus fail to transmit an action potential. This creates the anaesthetic effect by not merely preventing pain signals from propagating to the brain, but by stopping them before they begin. Careful titration allows for a high degree of selectivity in the blockage of sensory neurons, whereas higher concentrations also affect other modalities of neuron signaling.


The same principle applies for this drug's actions in the heart. Blocking sodium channels in the conduction system, as well as the muscle cells of the heart, raises the depolarization threshold, making the heart less likely to initiate or conduct early action potentials that may cause an arrhythmia.[35]


Lidocaine, the first amino amide–type local anesthetic, was first synthesized under the name 'xylocaine' by Swedish chemist Nils Löfgren in 1943.[36][37][38] His colleague Bengt Lundqvist performed the first injection anesthesia experiments on himself.[36] It was first marketed in 1949.

Recreational use

Lidocaine is not currently listed by the World Anti-Doping Agency as an illegal substance.[39] It is used as an adjuvant, adulterant, and diluent to street drugs such as cocaine and heroin.[40]

Compendial status

See also


  1. ^ "WHO Model List of Essential Medicines" (PDF). World Health Organization. October 2013. Retrieved 22 April 2014. 
  2. ^ Cepeda MS, Tzortzopoulou A, Thackrey M, Hudcova J, Arora Gandhi P, Schumann R (2010). "Adjusting the pH of lidocaine for reducing pain on injection". Cochrane Database Syst Rev (12): CD006581. PMID 21154371. doi:10.1002/14651858.CD006581.pub2. 
  3. ^ Derry, S; Wiffen, PJ; Moore, RA; Quinlan, J (24 July 2014). "Topical lidocaine for neuropathic pain in adults.". The Cochrane database of systematic reviews 7: CD010958. PMID 25058164. 
  4. ^ "New hope for tinnitus sufferers". BBC News. 9 January 2008. 
  5. ^ Kalcioglu MT, Bayindir T, Erdem T, Ozturan O. (2005). "Objective evaluation of the effects of intravenous lidocaine on tinnitus.". Hearing Research 199 (1-2): 81–8. PMID 15574302. doi:10.1016/j.heares.2004.08.004. 
  6. ^ Adcock JJ, Douglas GJ, Garabette M, Gascoigne M, Beatch G, Walker M, Page CP (February 2003). "RSD931, a novel anti-tussive agent acting on airway sensory nerves". Br. J. Pharmacol. 138 (3): 407–16. PMC 1573683. PMID 12569065. doi:10.1038/sj.bjp.0705056. 
  7. ^ Biller JA (2007). "Airway obstruction, bronchospasm, and cough". In Berger AM, Shuster JL, Von Roenn JH. Principles and practice of palliative care and supportive oncology. Hagerstwon, MD: Lippincott Williams & Wilkins. pp. 297–307. ISBN 978-0-7817-9595-1. Inhaled lidocaine is used to suppress cough during bronchoscopy. Animal studies and a few human studies suggest that lidocaine has an antitussive effect… 
  8. ^ Minogue SC, Ralph J, Lampa MJ (Oct 2004). "Laryngotracheal topicalization with lidocaine before intubation decreases the incidence of coughing on emergence from general anesthesia.". Anesthesia and Analgesia 99 (4): 1253–7, table of contents. PMID 15385385. doi:10.1213/01.ANE.0000132779.27085.52. 
  9. ^ Birsa LM, Verity PG, Lee RF (May 2010). "Evaluation of the effects of various chemicals on discharge of and pain caused by jellyfish nematocysts". Comp. Biochem. Physiol. C Toxicol. Pharmacol. 151 (4): 426–30. PMID 20116454. doi:10.1016/j.cbpc.2010.01.007. 
  10. ^ Morabito R, Marino A, Dossena S, La Spada G (Jun 2014). "Nematocyst discharge in Pelagia noctiluca (Cnidaria, Scyphozoa) oral arms can be affected by lidocaine, ethanol, ammonia and acetic acid.". Toxicon : official journal of the International Society on Toxinology 83: 52–8. PMID 24637105. doi:10.1016/j.toxicon.2014.03.002. 
  11. ^ Segal MM, Rogers GF, Needleman HL, Chapman CA (Dec 2007). "Hypokalemic sensory overstimulation.". Journal of child neurology 22 (12): 1408–10. PMID 18174562. doi:10.1177/0883073807307095. 
  12. ^ Hakim AJ, Grahame R, Norris P, Hopper C (February 2005). "Local anaesthetic failure in joint hypermobility syndrome". J R Soc Med 98 (2): 84–5. PMC 1079398. PMID 15684369. doi:10.1258/jrsm.98.2.84. 
  13. ^ a b "Lidocaine Hydrochloride and 5% Dextrose Injection". Safety Labeling Changes. FDA Center for Drug Evaluation and Research (CDER). January 2014. 
  14. ^ "Lidocaine Viscous: Drug Safety Communication - Boxed Warning Required - Should Not Be Used to Treat Teething Pain". FDA Center for Drug Evaluation and Research (CDER). June 2014. 
  15. ^ "Table 96–4. Drugs and Porphyria" (PDF). Merck Manual. Merck & Company, Inc. 2011. 
  16. ^ "Lidocaine - N01BB02". Drug porphyrinogenicity monograph. The Norwegian Porphyria Centre and the Swedish Porphyria Centre. strong clinical evidence points to lidocaine as probably not porphyrinogenic 
  17. ^ Khan, M. Gabriel (2007). Cardiac Drug Therapy (7th ed. ed.). Totowa, NJ: Humana Press. ISBN 9781597452380. 
  18. ^ Jackson D, Chen AH, Bennett CR (October 1994). "Identifying true lidocaine allergy". J Am Dent Assoc 125 (10): 1362–6. PMID 7844301. 
  19. ^ a b Australian Medicines Handbook. Adelaide, S. Aust: Australian Medicines Handbook Pty Ltd. 2006. ISBN 0-9757919-2-3. [page needed]
  20. ^ a b Nielsen, LJ; Lumholt, P; Hölmich, LR (27 October 2014). "[Local anaesthesia with vasoconstrictor is safe to use in areas with end-arteries in fingers, toes, noses and ears.]". Ugeskrift for laeger 176 (44). PMID 25354008. 
  21. ^ Baselt R (2008). Disposition of Toxic Drugs and Chemicals in Man (8th ed.). Foster City, CA: Biomedical Publications. pp. 840–4. ISBN 0-9626523-7-7. 
  22. ^ Picard J, Ward SC, Zumpe R, Meek T, Barlow J, Harrop-Griffiths W (February 2009). "Guidelines and the adoption of 'lipid rescue' therapy for local anaesthetic toxicity". Anaesthesia 64 (2): 122–5. PMID 19143686. doi:10.1111/j.1365-2044.2008.05816.x. 
  23. ^ Retrieved April 2014.  Missing or empty |title= (help)
  24. ^ "Product information for lidocaine ointment, USP 5%, spearmint flavored" (PDF). Product Insert. Taro Pharmaceutical Industries Ltd. Retrieved July 27, 2009. 
  25. ^ "Lidocaine Ointment Prescribing Information". Retrieved January 22, 2012. 
  26. ^ "Solarcaine". Schering-Plough Healthcare Products, Inc. Retrieved July 27, 2009. 
  27. ^ "Lidoderm (Lidocaine Patch 5%)". Our Products. Endo Pharmaceuticals. Retrieved 18 October 2012. 
  28. ^ Bernardo NP, Siqueira MEPB, De Paiva MJN, Maia PP (2003). "Caffeine and other adulterants in seizures of street cocaine in Brazil". International Journal of Drug Policy 14 (4): 331–4. doi:10.1016/S0955-3959(03)00083-5. 
  29. ^ Kimberly H (1997-12-15). "Take a big-picture approach when dealing with corneal sensation". Retrieved 2009-04-23. Lidocaine is more potent, with rapid diffusion and penetration. 
  30. ^ "UNITED STATES of America, Plaintiff-Appellee, v. Luis A. CUELLO, Alvaro Bastides-Benitez, John Doe, a/k/a Hugo Hurtado, and Alvaro Carvajal, Defendants-Appellants". Docket No. 78-5314. United States Court of Appeals, Fifth Circuit. 1979-07-25. 
  31. ^ Lewin NA, Nelson LH (2006). "Chapter 61: Antidysrhythmics". In Flomenbaum N, Goldfrank LR, Hoffman RL, Howland MD, Lewin NA, Nelson LH. Goldfrank's Toxicologic Emergencies (8th ed.). New York: McGraw-Hill. pp. 963–4. ISBN 0-07-143763-0. 
  32. ^ Thomson PD, Melmon KL, Richardson JA, Cohn K, Steinbrunn W, Cudihee R, Rowland M (April 1973). "Lidocaine pharmacokinetics in advanced heart failure, liver disease, and renal failure in humans". Ann. Intern. Med. 78 (4): 499–508. PMID 4694036. doi:10.7326/0003-4819-78-4-499. 
  33. ^ Collinsworth KA, Kalman SM, Harrison DC (1974). "The clinical pharmacology of lidocaine as an antiarrhythymic drug". Circulation 50 (6): 1217–30. PMID 4609637. doi:10.1161/01.CIR.50.6.1217. 
  34. ^ Carterall, William A. (2001). "Sodium Channels and Neuronal Hyperexcitability". Novartis Foundation Symposia 241. p. 206. ISBN 9780470846681. doi:10.1002/0470846682.ch14.  |chapter= ignored (help)
  35. ^ Sheu SS, Lederer WJ (Oct 1985). "Lidocaine's negative inotropic and antiarrhythmic actions. Dependence on shortening of action potential duration and reduction of intracellular sodium activity.". Circulation research 57 (4): 578–90. PMID 2412723. doi:10.1161/01.res.57.4.578. 
  36. ^ a b Löfgren N (1948). Studies on local anesthetics: Xylocaine: a new synthetic drug (Inaugural dissertation). Stockholm, Sweden: Ivar Heggstroms. OCLC 646046738. [page needed]
  37. ^ Löfgren N, Lundqvist B (1946). "Studies on local anaesthetics II". Svensk Kemisk Tidskrift 58: 206–17. 
  38. ^ Wildsmith JAW (2011). "Lidocaine: A more complex story than 'simple' chemistry suggests" (PDF). The Proceedings of the History of Anaesthesia Society 43: 9–16. 
  39. ^ "The 2010 Prohibited List International Standard" (PDF). The World Anti-Doping Code. World Anti-Doping Agency (WADA). 19 September 2009. 
  40. ^ "New York Drug Threat Assessment". National Drug Intelligence Center. November 2002. 
  41. ^ "Revision Bulletin: Lidocaine and Prilocaine Cream–Revision to Related Compounds Test". The United States Pharmacopeial Convention. November 30, 2007. 

External links