What is the maximum dose of lidocaine without epinephrine?

The maximum recommended dose of lidocaine without epinephrine is 4.5 mg/kg. For a 70 kg adult, this equals 315 mg. When epinephrine is added (typically 1:100,000 or 1:200,000), the maximum dose increases to 7 mg/kg (490 mg for a 70 kg adult) because epinephrine causes local vasoconstriction, slowing systemic absorption.

What are the signs and symptoms of local anesthetic systemic toxicity (LAST)?

LAST typically presents in a progressive sequence: early CNS symptoms include circumoral numbness, metallic taste, tinnitus, and lightheadedness. This may progress to visual disturbances, muscle twitching, and seizures. Cardiovascular toxicity follows with hypotension, bradycardia, and potentially cardiac arrest. Bupivacaine is particularly cardiotoxic. Symptoms can present atypically — cardiac arrest may occur without preceding CNS signs.

How do you treat local anesthetic systemic toxicity (LAST)?

Treatment follows the ASRA checklist: stop injection, call for help, manage airway, suppress seizures with benzodiazepines (avoid propofol in cardiovascular compromise), and initiate 20% lipid emulsion therapy — bolus 1.5 mL/kg over 1 minute, then infusion at 0.25 mL/kg/min. Repeat bolus once if needed. Continue infusion for at least 10 minutes after hemodynamic stability. Maximum recommended lipid dose is approximately 12 mL/kg. Avoid vasopressin, calcium channel blockers, beta-blockers, and large doses of epinephrine.

How do you convert local anesthetic percentage to mg/mL?

A 1% solution contains 10 mg/mL. To convert: multiply the percentage by 10. So 0.5% = 5 mg/mL, 1% = 10 mg/mL, 1.5% = 15 mg/mL, and 2% = 20 mg/mL. To find maximum volume: divide the total maximum dose (mg) by the concentration (mg/mL).

Are local anesthetic maximum doses different in children?

The mg/kg maximum doses are generally the same for children and adults. However, children have a lower total body mass, so the absolute maximum dose (in mg) is much lower. Neonates and infants are more susceptible to toxicity due to lower protein binding (less alpha-1 acid glycoprotein) and immature hepatic metabolism. Many clinicians use more conservative dosing in pediatric patients, and strict weight-based calculation is critical.

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Local Anesthetic Max Dose Calculator

Calculate maximum safe doses of lidocaine, bupivacaine, ropivacaine, and mepivacaine based on patient weight. Includes concentration-to-volume conversion and LAST emergency protocol.

Inputs

Patient Weight

Local Anesthetic

Concentration

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Enter patient weight to calculate maximum dose.

Disclaimer: For educational purposes only. Always verify doses with your institution's formulary, pharmacy, and applicable guidelines. Not a substitute for clinical judgment.

LAST Signs & Symptoms

Local Anesthetic Systemic Toxicity — Progressive Signs

EARLY Circumoral numbness, metallic taste, tinnitus, lightheadedness

CNS Visual disturbance, muscle twitching, agitation, seizures

CVS Hypotension, bradycardia, arrhythmias, cardiac arrest

⚠️ Atypical presentations occur — cardiac arrest may be the first sign, especially with bupivacaine.

Lipid Emulsion Rescue (Intralipid 20%)

ASRA Lipid Rescue Checklist

1. Bolus: 1.5 mL/kg IV over 1 minute
May repeat once if cardiovascular instability persists

2. Infusion: 0.25 mL/kg/min
Double rate if hypotension persists. Continue ≥10 min after stability.

3. Max dose: ~12 mL/kg
Over first 30 minutes

Pediatric Considerations

Same mg/kg limits apply, but lower absolute doses due to smaller body mass.
Neonates and infants: higher free drug fraction (low alpha-1 acid glycoprotein) — increased toxicity risk.
Immature hepatic metabolism (CYP1A2, CYP3A4) in infants <6 months prolongs drug half-life.
Use lean body weight for dosing in obese pediatric patients.
Consider maximum absolute dose caps: many clinicians limit lidocaine to 300 mg total regardless of weight.

Quick Reference — Max Doses

Agent	Without Epi	With Epi
Lidocaine	4.5 mg/kg	7 mg/kg
Bupivacaine	2.5 mg/kg	3 mg/kg
Ropivacaine	3 mg/kg
Mepivacaine	4.4 mg/kg	6.6 mg/kg

References

Neal JM, et al. The Third American Society of Regional Anesthesia and Pain Medicine Practice Advisory on Local Anesthetic Systemic Toxicity. Reg Anesth Pain Med. 2018;43(2):113–123.
Berde CB, Strichartz GR. Local Anesthetics. In: Miller's Anesthesia. 9th ed. Elsevier, 2020.
Berde CB, Strichartz GR. Local anesthetics. N Engl J Med. 2000;343(10):776.
Lexicomp / UpToDate Drug Dosing References.

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About This Tool

What Is a Local Anesthetic Max Dose Calculator?

This calculator determines the maximum safe dose of common local anesthetics — lidocaine, bupivacaine, ropivacaine, and mepivacaine — based on patient weight. It converts the maximum dose into the corresponding maximum volume at a given concentration, helping clinicians avoid local anesthetic systemic toxicity (LAST), a potentially fatal complication of local and regional anesthesia.

How Maximum Doses Are Calculated

The formula is: Maximum Dose (mg) = Weight (kg) × Max Dose per kg (mg/kg). To convert to volume: Maximum Volume (mL) = Maximum Dose (mg) ÷ Concentration (mg/mL). The concentration in mg/mL is the percentage multiplied by 10 (e.g., 1% = 10 mg/mL).

Why Epinephrine Increases the Maximum Dose

Epinephrine (adrenaline) added to local anesthetic solutions causes vasoconstriction at the injection site. This slows systemic absorption, allowing a larger total dose to be administered safely. For lidocaine, this raises the maximum from 4.5 mg/kg to 7 mg/kg. The effect is most pronounced in vascular tissues and less significant in already poorly perfused areas.

Local Anesthetic Systemic Toxicity (LAST)

LAST occurs when plasma levels of local anesthetic exceed the toxic threshold. Risk factors include inadvertent intravascular injection, excessive dosing, and injection into highly vascular tissue. The classic presentation follows a CNS-to-cardiovascular progression: circumoral numbness → tinnitus → seizures → cardiac arrest. However, atypical presentations are common — up to 40% of cases in the ASRA registry did not follow the classic sequence.

🔑 Clinical Pearls

Always aspirate before injecting — but a negative aspiration does not rule out intravascular injection.
Use the lowest effective dose and concentration.
Consider patient factors: hepatic disease, heart failure, pregnancy, and extremes of age increase susceptibility.
When using multiple local anesthetics, doses are additive for toxicity calculations.
Keep 20% lipid emulsion immediately available wherever local anesthetics are used.
Bupivacaine has the highest cardiotoxicity risk — the CC/CNS ratio is lower, meaning cardiac arrest may occur before seizures.

Key References

Neal JM, et al. The Third ASRA Practice Advisory on LAST. Reg Anesth Pain Med. 2018;43(2):113–123.
Berde CB, Strichartz GR. Local anesthetics. N Engl J Med. 2000;343(10):776.
El-Boghdadly K, et al. Local anesthetic systemic toxicity: current perspectives. Local Reg Anesth. 2018;11:35–44.

Formula last verified: February 2026