Lidocaine Dosing for Suturing
For suturing procedures, the maximum safe dose of lidocaine without epinephrine is 4.5 mg/kg (not to exceed 300 mg total), while lidocaine with epinephrine can be used at up to 7 mg/kg. 1, 2
Recommended Dosing Guidelines
Maximum Safe Doses
- For adults, lidocaine without epinephrine: 4.5 mg/kg (not exceeding 300 mg total) 2
- For adults, lidocaine with epinephrine: 7 mg/kg 1, 3
- For children over 3 years: 1.5-2 mg/kg without epinephrine (e.g., 75-100 mg for a 50 lb child) 2
Concentration and Formulation
- Standard concentration for infiltration anesthesia: 1% lidocaine solution (10 mg/mL) 3
- Adding epinephrine (typically 1:100,000 or 1:200,000) provides:
Clinical Considerations
Safety and Calculation Tips
- Calculate doses based on ideal body weight rather than actual body weight 1
- For a 70 kg adult, the maximum dose with epinephrine (7 mg/kg) would be 490 mg, equivalent to 49 mL of 1% solution 3
- Use incremental dosing for longer procedures to avoid toxicity 1
- Wait at least 4 hours between different local anesthetic interventions to prevent cumulative toxicity 1, 3
Special Situations
- Epinephrine can safely be used in digital blocks, contrary to historical concerns 3
- For patients with rapid lidocaine metabolism (enhanced hepatic clearance), consider:
Monitoring for Toxicity
- Early signs of lidocaine toxicity include circumoral numbness, facial tingling, slurred speech, metallic taste, and auditory changes 1, 3
- To reduce injection pain, consider buffering lidocaine with sodium bicarbonate (typically in a 1:9 or 1:10 ratio) 3
Practical Application
- For most simple laceration repairs, 3 mL of 1% lidocaine (30 mg) is well below the toxic threshold 3
- Higher doses of diluted lidocaine (up to 21.6 mg/kg with epinephrine) have been used safely in facial procedures, but standard guidelines should be followed for routine suturing 5
- Onset of action is 2-5 minutes for topical application and approximately 1 minute for infiltration 3