- 2%, 5ml (20mg/ml, 100mg total) ampoules (subcutaneous, IV)
- 4% spray (mucosa, topical)
- 4% gel, cream (topical)
- 5% patches (transdermal)
- 2% drops (ophthalmic and otic formulations)
(Updated February 2023)
Lidocaine is a synthetic local anesthetic of intermediate potency, and one of the most frequently used drugs in the ED. It has a reversible blocking effect on voltage-gated sodium channels, resulting in two main clinical usages: (i) interrupting nerve impulse propagation to achieve local or regional anesthesia, and (ii) inhibition of cardiac ion channels as a class IB antiarrhythmic drug (10).
Lidocaine has a wide variety of specific applications in the ED (1, 2, 3, 6, 14, 20, 22):
Antiarrhythmic for ventricular tachycardia
Local and regional anesthesia for wound repair and fracture closed reductions
Pain management for severe painful conditions such as renal colic and headache
Topical –spray or gel– anesthesia for awake intubation and other procedures such as bladder catheterization
Symptomatic treatment of cough
Transdermal patches to alleviate post-herpetic neuralgia and rib fractures
A recent double-blinded, randomized controlled trial discouraged use of IV lidocaine for renal colic as it did not show better outcomes than IV ketorolac (13).
Adult dose for local anesthesia (6, 12, 19, 17)
Up to 4.5 mg/kg (max 300mg per dose) subcutaneous infiltration within 2 hours.
Lidocaine can be diluted with normal saline down to 0.3-0.5% with a similar efficacy. Consider this option in large wounded areas or complex injuries that need procedures longer than 1-2 hours.
Lidocaine with epinephrine: 7mg/kg (max 500mg per dose), subcutaneous infiltration.
If no premixed solution is available, dilute epinephrine to a concentration of at least 1:100.000.
Dosing calculator: MDCalc® - Local Anesthetic Dosing Calculator
Adult dose for ventricular tachycardia (8, 9)
1 to 1.5 mg/kg; repeat with 0.5 to 0.75 mg/kg every 5 to 10 minutes as necessary (maximum cumulative dose: 3 mg/kg).
Consider continuous infusion of 1 to 4 mg/minute or 20 to 50 mcg/kg/minute.
US FDA-Labeled (16, 17, 18)
Acute management of ventricular arrhythmias occurring during cardiac manipulation such as cardiac surgery
Life-threatening arrhythmias, particularly those which are ventricular in origin, such as those which occur during acute myocardial infarction
Local or regional anesthesia by infiltration techniques such as percutaneous injection and regional anesthesia by peripheral nerve block techniques such as brachial plexus and intercostal and by central neural techniques such as lumbar and caudal epidural blocks
Otic pain (otic drops)
Ocular anesthesia (ocular drops)
Topical anesthesia (gels, patches, ointments, topical sprays)
IV pain management (renal colic, headache, other somatic pain, etc)
Lidocaine + epinephrine for subcutaneous infiltration
There are commercially available pre-mixed formulations that combine lidocaine and epinephrine (18).
Maximal dose of infiltrated lidocaine when administered with epinephrine: 7mg/kg (up to 500mg within 2 hours).
Epinephrine concentration should be diluted to at least 1:100.000 (usual ampoules of epinephrine in the ED are 1mg/1ml, same as 1:1.000).
Studies have shown that lidocaine + epinephrine versus lidocaine alone increases duration of local or regional anesthesia (19).
Duration of local anesthesia (12)
Lidocaine, subcutaneous: 30-60 minutes
Lidocaine + epinephrine, subcutaneous: 120-180 minutes
Consider lidocaine + epinephrine in complex wounds with expected prolonged repair durations.
This mixture is considered safe and is not associated with an increased risk of distal ischemia or necrosis (4).
In any case, caution and avoidance of epinephrine infiltration should be considered in cases of vascular insufficiency, overall vasculopathies, Raynaud disease, and other circulatory disorders.
Lidocaine for ventricular arrhythmias
Lidocaine, as a class IB antiarrhythmic agent, is approved by the US-FDA for treatment of ventricular arrhythmias associated with myocardial infarction and cardiac manipulation such as cardiac surgery (16).
Cardiac arrest with pulseless ventricular tachycardia (PVT) or ventricular fibrillation (VF): Evidence suggests that antiarrhythmics (amiodarone or lidocaine) provide little survival benefit in refractory PVT or VF (15). The ALPS study (7), a randomized trial of 3026 patients with out-of-hospital VT/VF refractory to initial defibrillation compared IV or IO amiodarone, lidocaine, and placebo and found no differences in survival to hospital discharge or functionally favorable survival in the overall study population, but in subgroup analysis in patients with witnessed collapse, amiodarone or lidocaine resulted in improved survival compared with placebo (28% vs 28% vs 23%).
The 2020 ACLS Guidelines recommend administering an antiarrhythmic drug (amiodarone or lidocaine) after the second defibrillation has been executed in the context of PVT/VF cardiac arrest as shown in the resuscitation algorithm (15).
Acute myocardial infarction-associated ventricular arrhythmias (VA)
According to the 2022 European Society of Cardiology guidelines to prevent and treat MI-associated VA (22), the first-line treatment includes urgent revascularization, and consider further revascularization if ventricular arrhythmia (VA) develops. Also other measures such as repletion of K+, Mg2+, and starting a beta-blocker should be considered initially. In cases of recurrent hemodynamically stable VA, if the previously mentioned measures fail to control the VA, amiodarone should be considered first. If there still is no response, lidocaine is recommended as an alternative (22). Studies have shown mixed results between amiodarone and lidocaine and there is consensus that more studies are needed to conclude a definite preference (5, 8). 2018 AHA guidelines on “Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death '' do not recommend a specific antiarrhythmic in VA associated with myocardial infarction (8).
The 2017 European Society of Cardiology “Guidelines for the Management of Acute Myocardial Infarction presenting with ST-segment Elevation” states over ventricular arrhythmias (VT and VF) that “the typical arrhythmia presentation is unstable, frequently polymorphic, and relatively fast VT, often degenerating into VF. Urgent reperfusion is most important as ischaemia often triggers these arrhythmias. Beta-blockers are recommended if no contraindications exist. Repetitive electrical cardioversion or defibrillation may be necessary. If there is no sufficient control, i.v. administration of amiodarone is recommended. In case of contraindications to amiodarone, i.v. lidocaine may be considered, although no studies comparing superiority of either drug in STEMI patients are available”. (9).
For a thorough review of adverse effects and warnings go to lidocaine HCl labeling (16, 17, 18).
Local Anesthetics Systemic Toxicity (LAST)
All local anesthetics may cause LAST when toxic plasma levels are reached, most often from accidental intravascular injection during other administration routes. Severity is usually dose-dependent. It provokes cardiovascular and neurologic toxicity:
Initially presents with lightheadedness, dizziness, followed by visual and auditory disturbances such as difficulty focusing and tinnitus.
Objective signs of neurotoxicity are usually excitatory and include shivering, muscular twitching, facial and distal extremities tremor.
Ultimately and more severe toxicity is manifested by generalized seizures followed by generalized CNS depression state. Seizure activity ceases, and respiratory depression occurs (12).
Local anesthetics have direct actions on the heart and peripheral blood vessels, as well as indirect actions on the circulation by blockade of sympathetic or parasympathetic efferent activity.
Negative inotropism and arrhythmias are caused by decreasing the conduction in Purkinje fibers and cardiomyocytes by prolonging recovery time (12).
It can cause hypotension, bradycardia and finally cardiac arrest (17).
Specific treatment for cardiovascular collapse or severe neurologic toxicity secondary to LAST consists of standard advanced cardiovascular life support if necessary and a rapid bolus of lipid emulsion (intralipid 20%) of 1,5 ml/kg (approximately 100ml in adults), followed by an infusion of 0.25ml/kg/min over the next 30-60 minutes. Maximal total dose is 10ml/kg (11).
Pregnancy and Lactation
US-FDA Pregnancy Risk Category B
Animal reproduction studies at doses up to 6.6 times the human dose have revealed no evidence of harm to the fetus caused by lidocaine HCl. There are, however, no adequate and well-controlled studies in pregnant women.
Lidocaine is considered compatible with breastfeeding in its multiple applications: local anesthetic (dermatological, dental), antiarrhythmic and epidural anesthesia.
It is excreted in breastmilk in insignificant quantities and no problems have been observed in infants whose mothers were taking it .
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BMJ (Open Access)
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Pubmed Central (Open Access)
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Pubmed Central (Open Access)
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NEJM (Open Access)
Article compendium The Bottom Line - ALPS
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Circulation (Open Access)
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European Heart Journal - ESC European Society of Cardiology (Open Access)
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Article compendium and discussion REBELCast - LIDOKET
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