What is the maximum safe dose of lidocaine (with and without epinephrine) for local infiltration in a wound?

Maximum Safe Dose of Lidocaine for Wound Infiltration

For wound infiltration in adults, use a maximum of 4.5 mg/kg (approximately 300 mg total) of lidocaine without epinephrine, or 7 mg/kg (approximately 500 mg total) with epinephrine. 1, 2, 3

Adult Dosing Guidelines

Without Epinephrine

• Maximum dose: 4.5 mg/kg 1, 3
• For a 70 kg adult: 315 mg maximum (15.75 mL of 2% solution or 31.5 mL of 1% solution) 2
• General recommendation: do not exceed 300 mg total dose 3

With Epinephrine

• Maximum dose: 7 mg/kg 1, 2, 3
• For a 70 kg adult: 490 mg maximum (24.5 mL of 2% solution or 49 mL of 1% solution) 2
• General recommendation: do not exceed 500 mg total dose 3
• Use epinephrine concentrations of 1:100,000 or 1:200,000 2, 4

Pediatric Dosing Guidelines

Children Over 3 Years

• Without epinephrine: 1.5-2.0 mg/kg maximum 2, 3
• With epinephrine: 3.0-4.5 mg/kg maximum 1, 2
• Example: A 5-year-old child weighing 23 kg (50 lbs) should receive no more than 75-100 mg 3

Infants Under 6 Months

• Reduce amide local anesthetic doses by 30% 1
• For topical LET (lidocaine, epinephrine, tetracaine): 0.175 mL/kg for children <17 kg 1
• For children >17 kg: 3 mL maximum 1

Critical Safety Measures

Calculation Before Administration

• Always calculate the maximum allowable dose in mg/kg before injecting to prevent overdose 1
• Remember: 1% lidocaine = 10 mg/mL; 2% lidocaine = 20 mg/mL 1

Injection Technique to Minimize Toxicity

• Aspirate before each injection to avoid intravascular administration 2
• Use incremental injections rather than bolus administration 2
• Inject slowly to reduce pain and systemic absorption 1

Pain Reduction Strategies

• Buffer lidocaine with sodium bicarbonate (typically 1:9 or 1:10 ratio) to decrease injection pain 1, 5, 4
• Warm the lidocaine before injection 1
• Use small-gauge needles (27-30 gauge) 1

Monitoring for Toxicity

Early Warning Signs (Monitor Continuously)

• Circumoral numbness 2, 4
• Facial tingling 2, 4
• Metallic taste 2, 4
• Slurred speech 2, 4
• Tinnitus or auditory changes 4

Severe Toxicity Signs

• Seizures (treat with benzodiazepines, avoid propofol if cardiovascular instability) 1
• Cardiovascular collapse (requires lipid emulsion therapy: 1.5 mL/kg of 20% lipid emulsion bolus) 1

Clinical Advantages of Adding Epinephrine

Hemodynamic Benefits

• Prolongs anesthesia duration by approximately 200% 5, 2, 4
• Slows systemic absorption, reducing peak blood levels and toxicity risk 5, 2
• Improves surgical field visualization through vasoconstriction 2, 4
• Reduces bleeding during wound repair 4

Safety in Digits

• Epinephrine is safe for use in fingers and toes despite historical concerns 5, 4
• The American Academy of Dermatology provides Level A (strongest) recommendation for epinephrine use in digits 5, 4

Special Circumstances

Multistage or Prolonged Procedures

• Maximum 500 mg lidocaine over several hours is acceptable 2
• Wait at least 90 minutes between repeat dosing for continuous techniques 1, 3

Avoid Cumulative Toxicity

• Do not use lidocaine within 4 hours of other local anesthetic interventions 4

Highly Vascular Areas

• Use lower doses in highly vascular areas where absorption is faster 1

Common Pitfalls to Avoid

• Never exceed 4.5 mg/kg without epinephrine or 7 mg/kg with epinephrine in adults 1, 2, 3
• Do not use concentrations higher than necessary—dilute if needed to stay within safe dose limits 3
• Do not forget to reduce doses by 30% in infants under 6 months 1
• Avoid bolus injections—always use incremental technique 2
• Do not ignore early toxicity signs—they precede life-threatening complications 2, 4