What is the typical dose of lidocaine (lido) without epinephrine (epi) used for numbing an area for a laceration repair with sutures?

Lidocaine Dosing for Laceration Repair

For laceration repair with sutures, the maximum recommended dose of lidocaine without epinephrine is 4.5 mg/kg (not to exceed 300 mg total) in adults. 1

Dosing Guidelines

• For adults, the maximum recommended dose of lidocaine without epinephrine is 4.5 mg/kg of body weight, with a general recommendation not to exceed 300 mg total 1, 2
• For children, the maximum recommended dose of lidocaine without epinephrine is 1.5-2.0 mg/kg 2
• For infants younger than 6 months, doses of amide local anesthetics should be decreased by 30% 2

Concentration and Volume Calculations

• Lidocaine is commonly available in concentrations of 1% (10 mg/mL) and 2% (20 mg/mL) 2
• The typical volume needed depends on the size of the laceration:
  • For small lacerations (<5 cm), approximately 3-5 mL of 1% lidocaine is usually sufficient 3
  • For facial lacerations, an average dose of 0.82 mL has been reported as effective when combined with other agents 3

Administration Techniques

• Inject slowly to minimize pain during administration 1
• For optimal anesthesia, allow 1-2 minutes after injection before beginning the procedure 2
• Lower doses should be used in very vascular areas to prevent rapid systemic absorption 2

Safety Considerations

• Calculate the maximum allowable volume before administration to avoid toxicity 2
• Signs of local anesthetic systemic toxicity (LAST) include circumoral numbness, facial tingling, slurred speech, metallic taste, auditory changes, and hallucinations 2
• More severe manifestations include seizures, central nervous system depression, and cardiac failure 2
• To prevent toxicity, avoid:
  • Rapid injection
  • Intravascular injection
  • Using multiple forms of lidocaine simultaneously 4

Alternative Options

• For patients with true lidocaine allergy (rare, approximately 1% of adverse reactions), consider:
  • Ester-type local anesthetics (minimal cross-reactivity with amide anesthetics) 2
  • 1% diphenhydramine (though it has a longer onset of action and limited efficacy) 2, 5
  • Bacteriostatic saline (0.9% benzyl alcohol in normal saline) 2
• Topical anesthetics like LET (lidocaine, epinephrine, tetracaine) can be effective for open wounds, providing anesthesia in 10-20 minutes 4, 6, 7

Common Pitfalls

• Underestimating the amount needed for adequate anesthesia, resulting in patient discomfort 6
• Exceeding maximum recommended doses, especially when treating multiple lacerations 2, 1
• Failing to account for patient weight when calculating maximum doses 1
• Not allowing sufficient time for onset of anesthesia before beginning the procedure 2

Remember that the dose of local anesthesia needed for most dermatologic procedures is well below the manufacturer-recommended maximum, making anesthetic toxicity in the dermatologic setting extremely rare 2.