Local Anesthetic Systemic Toxicity (LAST) Statistics (2026): Incidence, Recognition, and Rescue

What's in This Guide

01 How Often LAST Happens

LAST is genuinely rare, which is both reassuring and a challenge: rare events are the ones teams are least practiced at recognizing. The reported rates vary by setting and technique, so the honest picture is a range rather than a single number.

A dental anesthesia review reported LAST prevalence at approximately 0.27 per 1,000 local anesthetic administrations, describing it as possibly the most lethal adverse event associated with dental local anesthesia. In the wider regional anesthesia literature, systemic toxicity has been estimated to occur in about 0.03% of peripheral nerve blocks, roughly 0.27 episodes per 1,000 blocks, with some settings reporting rates as high as 1 in 500 and epidural figures near 4 in 10,000. In children the estimated rate is about 0.76 cases per 10,000 procedures. These numbers are small, but dentistry's enormous volume of local anesthetic use, detailed in our local anesthesia in dentistry statistics, means the absolute number of at-risk administrations is very large.

Source: Lipid emulsion therapy of LAST due to dental anesthesia (JDAPM, NCBI) | LAST management with intralipid and ASRA 2020 updates (NCBI)

02 How It Happens

Understanding the two pathways to toxic blood levels explains why prevention focuses on the specific habits it does. LAST is not an allergic reaction, it is a concentration problem.

LAST occurs when the blood concentration of local anesthetic reaches a toxic range, either by direct intravascular administration or by gradual absorption from tissue. At toxic concentrations, local anesthetics block voltage-gated sodium channels in the central nervous system and myocardium; as levels climb further, potassium channel blockade prolongs the QT interval and arrhythmias follow, which can end in cardiac arrest. Speed of absorption depends chiefly on the vascularity of the injected area. In dentistry the intravascular route is a real concern because highly vascular injection sites and nerve block techniques carry a measurable rate of inadvertent vessel entry, which is precisely why aspiration before injection is a core safety habit.

Source: Mechanisms and efficacy of IV lipid emulsion for LAST (NCBI)

03 Recognizing LAST

Recognition is where outcomes are won or lost. The classic progression gives a warning window, but that window is not guaranteed, and knowing both patterns is essential.

The textbook sequence begins with central nervous system excitation: ringing in the ears, a metallic taste, numbness or tingling around the mouth, blurred vision, dizziness, confusion, agitation, and slurred speech, progressing to muscle twitching and seizures, then to depression with drowsiness, coma, and respiratory arrest. Cardiovascular effects typically follow, including bradycardia, arrhythmias, hypotension, and cardiac arrest. Two caveats matter enormously in practice. First, roughly one in five patients present with cardiovascular signs first, with no neurologic warning. Second, sedated or anesthetized patients may not be able to report the early subjective symptoms at all, which delays diagnosis until hemodynamic changes appear, one more reason continuous monitoring matters at deeper levels of sedation, as covered in our general anesthesia in dentistry statistics.

Source: Local Anesthetic Systemic Toxicity clinical review (EMCrit IBCC) | LAST problem-based learning discussion (ASRA)

04 Who Is at Higher Risk

LAST risk is not evenly distributed. Both patient characteristics and drug choices shift the odds, and knowing the higher-risk profiles guides dose planning and vigilance.

Although pediatric LAST is rare overall, infants and neonates make up roughly 54% of reported pediatric cases, and in one systematic review of pediatric lipid emulsion treatment nearly 43% of patients were under one year old. Older adults are also disproportionately affected, with reduced muscle mass, slower circulation, decreased renal function, and multiple coexisting conditions cited as contributors. Drug choice matters too: bupivacaine carries greater cardiotoxic risk than ropivacaine or lidocaine, while in dentistry lidocaine and articaine are the dominant agents and have comparatively favorable profiles. Additional risk factors include hepatic or cardiac impairment, low body weight, and any circumstance where large total doses are used. For children specifically, weight-based dosing discipline is paramount, a theme that runs through our pediatric sedation statistics.

Source: Lipid emulsion treatment for pediatric LAST, systematic review (NCBI) | LAST following inadvertent IV infusion in infants (NCBI)

05 Lipid Emulsion Rescue

The single biggest change in LAST outcomes came from a specific antidote. Lipid emulsion therapy transformed a frequently catastrophic event into one that is often survivable with prompt treatment.

Since around 2010, 20% intravenous lipid emulsion has been the definitive treatment for LAST, often called lipid rescue therapy. It works as a lipid sink, sequestering lipophilic local anesthetic away from its receptor targets while also improving cardiac perfusion, conduction, and contractility. Under ASRA guidance, treatment is a bolus of roughly 1.5 mL/kg of 20% emulsion followed by an infusion near 0.25 mL/kg/min, continued for at least 10 minutes after hemodynamic stability, with a typical ceiling around 10 mL/kg in the first 30 minutes. Critically, resuscitation for LAST differs from standard ACLS: lidocaine must not be given as an antiarrhythmic because it would worsen the underlying toxicity, calcium channel blockers and beta blockers are avoided, and epinephrine is used in reduced doses. In refractory cases, extracorporeal support may be required.

Source: Local anesthetics, adverse events and dental practice (Oral Health Group) | LAST under anesthesia, management essentials (Medscape)

06 Summary Table: Every Statistic

07 Frequently Asked Questions