What is the recommended dosing for lidocaine (local anesthetic) in dermatological procedures?

Lidocaine Dosing in Dermatological Procedures

For adults, no more than 4.5 mg/kg of lidocaine without epinephrine and 7.0 mg/kg of lidocaine with epinephrine should be administered in a single dermatological treatment. 1

Maximum Safe Dosing Guidelines

Adult Dosing

• Plain lidocaine: Maximum 4.5 mg/kg
• Lidocaine with epinephrine: Maximum 7.0 mg/kg
• For multistage procedures (e.g., Mohs surgery): Maximum 500 mg (50 mL of 1% solution) delivered over several hours 1

Pediatric Dosing

• Plain lidocaine: Maximum 1.5-2.0 mg/kg
• Lidocaine with epinephrine: Maximum 3.0-4.5 mg/kg 1

Practical Application in Common Procedures

Recent research shows that typical volumes used in dermatologic procedures are well within safety limits:

• Mean volume for skin cancer excision: 3.44 mL of 1% lidocaine
• Mean volume for reconstruction: 11.70 mL of 1% lidocaine 2

Safety Considerations

Steps to Reduce Risk of Systemic Toxicity

• Use the lowest effective dose of anesthetic
• Aspirate before injection to avoid intravascular administration
• Use incremental injections rather than bolus dosing
• Continuously monitor and communicate with patient for early signs of toxicity 1

Signs of Lidocaine Toxicity (Progressive)

1. Initial symptoms: Circumoral numbness, facial tingling, slurred speech, metallic taste, auditory changes
2. May progress to: Hypertension, tachycardia, hallucinations
3. Severe cases: Seizures, CNS depression, cardiac failure 1

Special Populations

Patients with Lidocaine Allergy

True lidocaine allergy is rare (approximately 1% of adverse reactions) 1. Options include:

• Ester-type local anesthetics (minimal cross-reactivity with amide anesthetics)
• 1% diphenhydramine injection (note: longer onset of action - 5 min vs. 1 min for lidocaine)
• Bacteriostatic normal saline (0.9% benzyl alcohol in normal saline) 1

Patients with Cardiovascular Disease

• Small amounts of lidocaine with epinephrine appear safe in patients with stable cardiovascular disease
• For questionable cases, consult with the patient's cardiologist 1

Epinephrine Considerations

• Most common concentrations: 1:100,000 and 1:200,000
• Concentrations of 1:50,000,1:100,000, and 1:200,000 all provide similar vasoconstriction
• Use lowest effective concentration to minimize palpitations and anxiety 1

Common Pitfalls to Avoid

1. Exceeding maximum recommended doses, especially in prolonged procedures
2. Failure to recognize early signs of toxicity
3. Not accounting for patient weight when calculating maximum doses
4. Improper technique leading to intravascular injection
5. Assuming all topical anesthetics have similar absorption rates - significant interindividual differences exist 3

For optimal safety and efficacy, always calculate the maximum dose based on patient weight before the procedure, use the lowest effective concentration, and monitor for signs of toxicity throughout the procedure.