|Systematic (IUPAC) name|
|Pregnancy cat.||A (AU) B (US)|
|Legal status||Prescription Only (S4) (AU) Rx Only (U.S.) (excluding 1%) (US)|
|Routes||IV, subcutaneous, topical|
|Metabolism||Hepatic, 90% CYP1A2-mediated|
|ATC code||N01 C01 D04 S02 C05|
|Mol. mass||234.34 g/mol|
|Melt. point||68 °C (154 °F)|
| (what is this?)
Lidocaine (INN) //, xylocaine, or lignocaine (former BAN) // is a common local anesthetic and antiarrhythmic drug. Lidocaine is used topically to relieve itching, burning and pain from skin inflammations, injected as a dental anesthetic or as a local anesthetic for minor surgery.
Lidocaine, the first amino amide–type local anesthetic, was first synthesized under the name xylocaine by Swedish chemist Nils Löfgren in 1943. His colleague Bengt Lundqvist performed the first injection anesthesia experiments on himself. It was first marketed in 1949.
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, on the other hand, has the advantage of a rapid onset of action. Epinephrine (aka adrenaline) vasoconstricts arteries reducing bleeding and also delays the resorption of lidocaine, almost doubling the duration of anaesthesia. For surface anesthesia several formulations are available that can be used e.g. for endoscopies, before intubations etc. Buffering the pH of lidocaine makes local freezing less painful.
Topical lidocaine has been shown in some patients to relieve the pain of postherpetic neuralgia (a complication of shingles), though there is not enough study evidence to recommend it as a first-line treatment. It also has uses as a temporary fix for tinnitus. Although not completely curing the illness, it has been shown to reduce the effects by around two thirds.
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).
However, amiodarone has been replacing lidocaine as the first-line pharmacologic management of ventricular tachycardia.
A routine prophylactic administration is no longer recommended for acute cardiac infarction; the overall benefit of this measure is not convincing.
Lidocaine has also been efficient in refractory cases of status epilepticus.
Contraindications for the use of lidocaine include:
- Heart block, second or third degree (without pacemaker)
- Severe sinoatrial block (without pacemaker)
- Serious adverse drug reaction to lidocaine or amide local anaesthetics
- Concurrent treatment with quinidine, flecainide, disopyramide, procainamide (Class I antiarrhythmic agents)
- Prior use of Amiodarone hydrochloride
- Hypotension not due to Arrhythmia
- Accelerated idioventricular rhythm
- Porphyria, especially Acute Intermittent Porphyria (AIP); lidocaine has been classified as porphyrogenic although clinical evidence suggests that it is not.
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.
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. CNS effects may include CNS excitation (nervousness, tingling around the mouth (also known as circumoral paraesthesia), tinnitus, tremor, dizziness, blurred vision, seizures) followed by depression, and with increasingly heavier exposure: drowsiness, loss of consciousness, respiratory depression and apnoea). Cardiovascular effects include hypotension, bradycardia, arrhythmias, and/or cardiac arrest – some of which may be due to hypoxemia secondary to respiratory depression.
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/minute). 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.
Overdosage with lidocaine can be a result of excessive administration via topical or parenteral routes, accidental oral ingestion of topical preparations by children, 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 overdosage. It is important in the interpretation of analytical results to recognize that lidocaine is often routinely administered intravenously as an antiarrhthymic agent in critical cardiac care situations. Treatment with intravenous lipid emulsions (used for parental feeding) to reverse the effects of local anaesthetic toxicity is becoming more commonplace.
Insensitivity to lidocaine
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. 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.
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
- 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
- Topical gel (as with Aloe vera gels that include lidocaine)
- 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 as "Lidoderm" - and since 2007 in the UK by Grünenthal as "Versatis"
- Topical aerosol spray
- Inhaled via a nebulizer
- As a component of a GI cocktail used in emergency rooms
Adulterant in cocaine
Lidocaine is often added to cocaine as a diluent. Cocaine numbs the gums when applied, and since lidocaine causes stronger numbness, a user gets the impression of high-quality cocaine when in actuality, the user is receiving a diluted product.
Lidocaine is approximately 95% metabolized (dealkylated) in the liver 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.
The elimination half-life of lidocaine is approximately 90–120 minutes in most patients. This may be prolonged in patients with hepatic impairment (average 343 minutes) or congestive heart failure (average 136 minutes).
Lidocaine alters signal conduction in neurons by blocking the fast voltage gated sodium (Na+) channels in the neuronal cell membrane that are responsible for signal propagation. 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 will also affect other modalities of neuron signaling.
Lidocaine is not currently listed by the World Anti-Doping Agency as an illegal substance. Lidocaine is used as an adjuvant, adulterant, and diluent to illegal street drugs (e.g. cocaine). (See U.S. DEA web site).
Notes and references
- Löfgren N (1948). Studies on local anesthetics: Xylocaine: a new synthetic drug (Inaugural dissertation). Stockholm, Sweden: Ivar Heggstroms. OCLC 646046738.[page needed]
- Löfgren N, Lundqvist B (1946). "Studies on local anaesthetics II". Svensk Kemisk Tidskrift 58: 206–17.
- Wildsmith JAW (2011). "Lidocaine: A more complex story than 'simple' chemistry suggests". The Proceedings of the History of Anaesthesia Society 43: 9–16.
- 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. doi:10.1002/14651858.CD006581.pub2. PMID 21154371.
- Khaliq W, Alam S, Puri N (2007). "Topical lidocaine for the treatment of postherpetic neuralgia". Cochrane Database Syst Rev (2): CD004846. doi:10.1002/14651858.CD004846.pub2. PMID 17443559.
- "New hope for tinnitus sufferers". BBC News. 9 January 2008.
- 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. doi:10.1038/sj.bjp.0705056. PMC 1573683. PMID 12569065.
- 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…"
- 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. doi:10.1016/j.cbpc.2010.01.007. PMID 20116454.
- "Table 96–4. Drugs and Porphyria". Merck Manual. Merck & Company, Inc. 2011.
- "Lidocaine - N01BB02". Drug porphyrinogenicity monograph. The Norwegian Porphyria Centre (NAPOS) and The Swedish Porphyria Centre. "strong clinical evidence points to lidocaine as probably not porphyrinogenic"
- Jackson D, Chen AH, Bennett CR (October 1994). "Identifying true lidocaine allergy". J Am Dent Assoc 125 (10): 1362–6. PMID 7844301.
- Australian Medicines Handbook. Adelaide, S. Aust: Australian Medicines Handbook Pty Ltd. 2006. ISBN 0-9757919-2-3.[page needed]
- Baselt R (2008). Disposition of Toxic Drugs and Chemicals in Man (8th ed.). Foster City, CA: Biomedical Pubilcations. pp. 840–4. ISBN 0-9626523-7-7.
- 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. doi:10.1111/j.1365-2044.2008.05816.x. PMID 19143686.
- 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. doi:10.1258/jrsm.98.2.84. PMC 1079398. PMID 15684369.
- "Product information for lidocaine ointment, USP 5%, spearmint flavored". Product Insert. Taro Pharmaceutical Industries Ltd. Retrieved July 27, 2009.
- "Lidocaine Ointment Prescribing Information". Drugs.com. Retrieved January 22, 2012.
- "Solarcaine". Schering-Plough Healthcare Products, Inc. Retrieved July 27, 2009.
- "Lidoderm (Lidocaine Patch 5%)". Our Products. Endo Pharmaceuticals. Retrieved 18 October 2012.
- 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.
- 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."
- "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.
- Reilly TJ (1999). "The Preparation of Lidocaine". Journal of Chemical Education 76 (11): 1557. doi:10.1021/ed076p1557.
- US patent 2441498, Bengt JL, Niels, ML, "Alkyl glycinanilides", issued 1948-05-11, assigned to Astra Apotekarnes Kem FAB
- 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.
- 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. doi:10.7326/0003-4819-78-4-499. PMID 4694036.
- Carterall, William A. (2001). "Molecular Mechanisms of Gating and Drug Block of Sodium Channels". Sodium Channels and Neuronal Hyperexcitability. Novartis Foundation Symposia 241. p. 206. doi:10.1002/0470846682.ch14. ISBN 9780470846681.
- "The 2010 Prohibited List International Standard". The World Anti-Doping Code. World Anti-Doping Agency (WADA). 19 September 2009.
- "Revision Bulletin: Lidocaine and Prilocaine Cream–Revision to Related Compounds Test". The United States Pharmacopeial Convention. November 30, 2007.