Maximum Dose of Lidocaine for Local Anesthesia and Systemic Use
The maximum safe dose of lidocaine without epinephrine is 4.5 mg/kg in adults (not to exceed 300 mg total), while with epinephrine it increases to 7.0 mg/kg (not to exceed 500 mg total). 1, 2
Local Anesthesia Dosing Guidelines
- For local anesthesia without epinephrine, the maximum safe dose is 4.5 mg/kg in adults and 1.5-2.0 mg/kg in children 1
- When combined with epinephrine (which provides local vasoconstriction and reduces systemic absorption), the maximum safe dose increases to 7.0 mg/kg in adults and 3.0-4.5 mg/kg in children 1, 3
- For dental procedures, 2% lidocaine with 1:100,000 epinephrine provides approximately 90-200 minutes of pulpal anesthesia 3
- The FDA recommends that the maximum dose of lidocaine should not exceed 300 mg in adults, regardless of calculation method 2
Systemic Use and Special Applications
- For intravenous administration, the loading dose should not exceed 1.5 mg/kg given over 10 minutes, with a maximum hourly dose of 120 mg/hour 4
- For tumescent anesthesia (subcutaneous infiltration of dilute lidocaine):
Route-Specific Dosing
- Retrobulbar injection: 3-5 mL (120-200 mg) for a 70 kg person 2
- Transtracheal injection: 2-3 mL, rarely exceeding 5 mL (200 mg) total 2
- Topical application for laryngoscopy/bronchoscopy: 1-5 mL (40-200 mg) 2
- Lidocaine 5% patch: Pharmacokinetic studies have shown systemic levels remain within safe range with up to four patches in 24 hours 7
Risk Factors and Precautions
- Calculate dosage using ideal body weight rather than actual body weight 4
- Reduce doses for elderly patients, debilitated patients, and those with hepatic or renal impairment 2
- Do not use lidocaine within 4 hours of other local anesthetic interventions to prevent cumulative toxicity 4, 1
- Remove topical lidocaine plasters before starting any intravenous lidocaine infusion 4
- Occlusive dressings can significantly increase systemic absorption of topical lidocaine (up to 3x higher serum levels) 8
Monitoring for Toxicity
- Early signs of lidocaine toxicity include circumoral numbness, facial tingling, slurred speech, tinnitus, and light-headedness 4, 1
- Progressive signs include muscle twitching, loss of consciousness, and respiratory arrest 4
- Severe toxicity can manifest as myocardial depression, cardiac arrhythmias, and ventricular arrest 4
- Serum lidocaine levels above 6 μg/mL are associated with mild toxicity 6
Special Considerations
- The addition of epinephrine allows for higher maximum doses due to local vasoconstriction that reduces systemic absorption 3
- Lidocaine is contraindicated in advanced liver failure due to decreased clearance 7
- Use with caution in patients with electrolyte disorders, seizure disorders, renal impairment, pregnancy/breastfeeding, or neurological disorders 4, 1
Remember that these maximum doses are guidelines, and the lowest effective dose should always be used to minimize risk of toxicity 2, 9.