Lidocaine Dosing for Suturing
For suturing in adults, use a maximum dose of 4.5 mg/kg (up to 300 mg total) of lidocaine without epinephrine, or 7 mg/kg with epinephrine. 1, 2
Adult Dosing Guidelines
The FDA-approved maximum dose for lidocaine without epinephrine is 4.5 mg/kg (2 mg/lb) of body weight, with a total maximum of 300 mg. 2 When epinephrine is added, this increases to 7 mg/kg. 1, 3, 4
Practical Calculation Examples:
- 1% lidocaine = 10 mg/mL 2
- For a 70 kg adult without epinephrine: maximum 315 mg (31.5 mL of 1% lidocaine), but limit to 300 mg total 2
- For a 70 kg adult with epinephrine: maximum 490 mg (49 mL of 1% lidocaine) 1
Pediatric Dosing
For children over 3 years of age, use 3.0-4.5 mg/kg with epinephrine or 1.5-2.0 mg/kg without epinephrine. 1 For example, a 5-year-old child weighing 50 lbs should receive no more than 75-100 mg (1.5-2 mg/lb). 2
For children under 17 kg requiring topical LET (lidocaine-epinephrine-tetracaine), use 0.175 mL/kg; for those over 17 kg, use 3 mL total. 1 This dosing is based on the maximum safe dose of 5 mg/kg of lidocaine. 1
Pain Reduction Techniques During Injection
To minimize injection pain, buffer lidocaine with bicarbonate, warm the solution before injection, and inject slowly with a small-gauge needle. 1 Buffered lidocaine can be prepared in advance and remains stable for up to 30 days. 1
Special Considerations for Extended Procedures
For lengthy procedures like Mohs surgery, incremental dosing over extended time periods appears safe. 1 One study demonstrated that 500 mg of 1% lidocaine delivered incrementally over an average of 8 hours produced no toxicity and serum levels remained below toxic thresholds. 1
Critical Safety Warnings
Monitor for early signs of local anesthetic systemic toxicity (LAST), which include circumoral numbness, facial tingling, slurred speech, metallic taste, auditory changes, and hallucinations. 1, 3, 4 These symptoms may progress to seizures or cardiac arrest in severe cases. 1
Avoid combining lidocaine with other local anesthetic interventions within 4 hours, as this increases toxicity risk. 3, 4 Calculate maximum doses based on ideal body weight rather than actual body weight. 4
Alternative Anesthetics for Lidocaine Allergy
For patients with true lidocaine allergy (representing only 1% of adverse reactions), switch to an ester-type local anesthetic, as cross-reaction is rare. 1, 4 Other options include 1% diphenhydramine (though with longer onset of 5 minutes versus 1 minute for lidocaine) or bacteriostatic saline (0.9% benzyl alcohol), which may be less painful than diphenhydramine when combined with epinephrine. 1, 4