What is the recommended dose of lidocaine for wound anesthesia?

From the Guidelines

The maximum safe dose of lidocaine for local anesthesia of a wound is 4.5 mg/kg without epinephrine or 7 mg/kg with epinephrine. For an average 70 kg adult, this translates to approximately 315 mg of lidocaine without epinephrine or 490 mg with epinephrine, as recommended by the guidelines for the use of local anesthesia in office-based dermatologic surgery 1. In practical terms, when using 1% lidocaine (10 mg/mL), you can use up to 31.5 mL without epinephrine or 49 mL with epinephrine. For 2% lidocaine (20 mg/mL), the volumes would be 15.75 mL without epinephrine or 24.5 mL with epinephrine.

When anesthetizing a wound, it is essential to:

• Inject slowly around the wound edges
• Wait 5-10 minutes for full effect
• Avoid injecting into infected areas
• Avoid using epinephrine-containing solutions on end arteries (fingers, toes, nose, ears, penis), as stated in the guidelines 1

Key considerations for lidocaine use include:

• Lidocaine works by blocking sodium channels in nerve membranes, preventing the generation and conduction of nerve impulses
• Signs of lidocaine toxicity include perioral numbness, metallic taste, dizziness, tinnitus, and in severe cases, seizures or cardiac arrhythmias
• The maximum safe dose of local infiltrated anesthesia is crucial to prevent toxicity, and the recommended doses should not be exceeded 1

From the Research

Lidocaine Dosage for Wound Anesthesia

• The optimal dosage of lidocaine for wound anesthesia is not explicitly stated in the provided studies, but we can look at the concentrations and volumes used in various studies to get an idea of the typical usage.
• A study published in the Journal of drugs in dermatology 2 used a solution of 3 mL of 1% lidocaine + epinephrine in 30 mL of bacteriostatic 0.9% sodium chloride, which is a 1:10 ratio.
• Another study published in the Aesthetic surgery journal 3 compared five commonly-available lidocaine preparations, including LMX-4 (4% lidocaine), Topicaine (4% lidocaine), and a generic EMLA preparation (2.5% lidocaine/2.5% prilocaine).
• A study published in the Dental clinics of North America 4 found that lidocaine is effective at concentrations between 5% and 20% for intraoral topical anesthesia.
• A study published in the Revista brasileira de anestesiologia 5 used 3 mL of 1% lidocaine for subcutaneous infiltration and found that the median time to achieve anesthesia in 50% and 95% of patients was 25 seconds and 53 seconds, respectively.

Concentration and Volume of Lidocaine

• The concentration of lidocaine used in the studies ranged from 1% to 20%, with the most common concentration being 1% or 4%.
• The volume of lidocaine used in the studies ranged from 3 mL to 50 mL, with the most common volume being 3 mL to 5 mL.
• It's worth noting that the dosage of lidocaine should be individualized based on the patient's weight, age, and medical history, as well as the location and size of the wound 6, 3.

Administration of Lidocaine

• Lidocaine can be administered via infiltration, where the anesthetic is injected directly into the tissue surrounding the wound 2, 5.
• The administration of lidocaine should be done slowly and carefully to minimize discomfort and avoid toxicity 6, 3.
• It's also important to follow proper techniques for wound cleaning and dressing after anesthesia has been administered 6.