What is the recommended dose of lidocaine (local anesthetic) for wound suturing?

Lidocaine Dosing for Wound Suturing

For adults, prepare no more than 4.5 mg/kg (maximum 300 mg) of lidocaine without epinephrine, or 7 mg/kg (maximum 490 mg for a 70 kg adult) with epinephrine for wound suturing. 1, 2, 3

Adult Dosing Guidelines

Maximum safe doses for infiltrative anesthesia:

• Without epinephrine: 4.5 mg/kg, not exceeding 300 mg total 1, 3
• With epinephrine: 7 mg/kg 1, 2

Practical volume calculations:

• For 1% lidocaine (10 mg/mL): A 70 kg adult can receive up to 30 mL without epinephrine or 49 mL with epinephrine 2
• For 0.5% lidocaine (5 mg/mL): Double these volumes 3

Pediatric Dosing Guidelines

For children over 3 years of age:

• Without epinephrine: 1.5-2.0 mg/kg 1, 2
• With epinephrine: 3.0-4.5 mg/kg 1, 2

For topical LET (lidocaine-epinephrine-tetracaine) application:

• Children <17 kg: 0.175 mL/kg (based on maximum 5 mg/kg lidocaine) 1, 2
• Children >17 kg: 3 mL total 1, 2

Pain Reduction Techniques During Injection

To minimize injection pain, implement these evidence-based techniques:

• Buffer lidocaine with sodium bicarbonate (remains stable for 30 days when pre-mixed) 1, 2
• Warm the lidocaine solution before injection 1, 2
• Use a small-gauge needle and inject slowly 1, 2

Special Considerations for Extended Procedures

For lengthy multi-stage procedures like Mohs surgery:

• Maximum of 500 mg (50 mL of 1% lidocaine) delivered incrementally over several hours is safe 1
• This dosing has been validated with serum levels remaining below toxic thresholds 1

Critical Safety Warnings

Monitor for early signs of local anesthetic systemic toxicity (LAST):

• Circumoral numbness, facial tingling, metallic taste 1, 2
• Pressured or slurred speech, auditory changes, hallucinations 1
• Progression to seizures or cardiovascular collapse in severe cases 1

Essential safety measures:

• Aspirate before each injection to avoid intravascular administration 1
• Use incremental injections rather than bolus administration 1
• Do not combine with other local anesthetics within 4 hours 2
• Use the lowest effective concentration and dose 3

Alternative Anesthetics for Lidocaine Allergy

For patients with true lidocaine allergy (rare, only 1% of adverse reactions):

• Switch to ester-type local anesthetics (cross-reaction is rare) 1, 2
• Consider 1% diphenhydramine (longer onset: 5 minutes vs 1 minute for lidocaine) 1
• Bacteriostatic normal saline (0.9% benzyl alcohol) may be less painful than diphenhydramine when combined with epinephrine 1

Common Pitfalls to Avoid

Do not exceed manufacturer-recommended maximum doses even though the actual toxic threshold may be higher—these limits provide a safety margin 1, 3

Do not use actual body weight for obese patients—this can lead to inadvertent overdosing; use ideal body weight instead 2

Do not forget to account for topical anesthetics (like LET gel) when calculating total lidocaine dose, as systemic absorption occurs 1, 2