What is the maximum dose of epinephrine (adrenaline) and lidocaine when mixed together for a procedure?

Maximum Dose Calculation for Combined Epinephrine and Lidocaine

When epinephrine and lidocaine are mixed for a procedure, the maximum safe dose of lidocaine is 7 mg/kg with epinephrine, while epinephrine should be limited to the lowest effective concentration (typically 1:100,000 to 1:200,000) to minimize cardiovascular risks. 1

Understanding Maximum Dose Limits

Lidocaine Maximum Dose

• With epinephrine: 7 mg/kg (medical use) or 4.4 mg/kg (dental use) 1
• Without epinephrine: 4-4.4 mg/kg 1
• Duration of action: 90-200 minutes 1

Epinephrine Considerations

• Common concentrations in dermatologic surgery: 1:100,000 and 1:200,000 1
• All concentrations between 1:50,000 to 1:200,000 provide similar vasoconstriction effects 1
• Lower concentrations (1:800,000 to 1:3,200,000) still prolong anesthesia but may provide less effective vasoconstriction 1

Calculation Method

1. Calculate maximum lidocaine dose first:

   • Patient weight (kg) × 7 mg/kg = maximum mg of lidocaine with epinephrine
   • Example: 70 kg patient → 70 × 7 = 490 mg maximum lidocaine

2. Convert lidocaine percentage to mg/mL:

   • 1% lidocaine = 10 mg/mL
   • 2% lidocaine = 20 mg/mL

3. Calculate maximum volume:

   • Maximum mg ÷ concentration (mg/mL) = maximum volume (mL)
   • Example: 490 mg ÷ 10 mg/mL (1% solution) = 49 mL maximum volume

4. Check epinephrine concentration:

   • Use lowest effective concentration (typically 1:100,000 or 1:200,000)
   • Avoid exceeding recommended epinephrine doses, especially in patients with cardiovascular concerns

Special Considerations

Anatomic Location

• For procedures on extremities (fingers, toes, penis, ears, nose), epinephrine can be safely used despite traditional teaching 1
• Current evidence supports that epinephrine is safe for use in penile skin surgery 1

Patient Factors

• Reduce lidocaine dose by 30% in infants younger than 6 months 1
• Patients with stable cardiac disease can safely receive small amounts of local anesthesia with epinephrine 1
• For patients with questionable cardiovascular status, consultation with the patient's cardiologist is recommended 1

Safety Precautions

• Calculate maximum allowable safe dosage before administration 1
• Use lower doses when injecting into vascular tissues 1
• Aspirate frequently to minimize the likelihood of intravascular injection 1
• Monitor vital signs at least every 5 minutes when high doses or amide local anesthetics are required 1

Toxicity Management

• Early recognition of toxicity signs: circumoral numbness, facial tingling, light-headedness, tinnitus 2
• Have 20% lipid emulsion readily available for treatment of local anesthetic toxicity 1
• For epinephrine-induced vasospasm, phentolamine (0.1-0.2 mg/kg up to 10 mg) can be injected intradermally at extravasation site 1, 3

By following these guidelines and carefully calculating maximum doses based on patient weight and other factors, clinicians can safely administer combined epinephrine and lidocaine for procedures while minimizing risks of toxicity.