What is the recommended dosage of lignocaine (lidocaine) 2% with and without adrenaline (epinephrine) for local infiltration anesthesia in a 70 kg adult?

Recommended Dosage of Lignocaine 2% With and Without Adrenaline for Local Infiltration

For a 70 kg adult undergoing local infiltration anesthesia, the maximum safe dose is 315 mg (15.75 mL) of lignocaine 2% without adrenaline, or 490 mg (24.5 mL) of lignocaine 2% with adrenaline. 1, 2

Adult Dosing Guidelines

Lignocaine 2% Without Adrenaline

• Maximum dose: 4.5 mg/kg 1, 2
• For a 70 kg adult: 4.5 mg/kg × 70 kg = 315 mg total 1
• Volume calculation: 315 mg ÷ 20 mg/mL = 15.75 mL of 2% solution 1
• The FDA recommends not exceeding 300 mg total dose in general practice 2

Lignocaine 2% With Adrenaline (Epinephrine)

• Maximum dose: 7.0 mg/kg 1, 2
• For a 70 kg adult: 7.0 mg/kg × 70 kg = 490 mg total 1
• Volume calculation: 490 mg ÷ 20 mg/mL = 24.5 mL of 2% solution 1
• The FDA recommends not exceeding 500 mg total dose in general practice 2

Key Clinical Advantages of Adding Adrenaline

Adding adrenaline to lignocaine provides significant clinical benefits beyond just allowing higher doses: 3, 4

• Prolongs duration of anesthesia by approximately 200% 4
• Slows systemic absorption, reducing peak blood levels and toxicity risk 4
• Improves surgical field visualization through vasoconstriction 4
• Standard concentrations used are 1:100,000 or 1:200,000 3, 5

Critical Safety Measures to Prevent Toxicity

Always implement these steps when administering local infiltration anesthesia: 1

• Use the lowest effective dose for the procedure 1, 2
• Aspirate before each injection to avoid intravascular administration 1, 2
• Use incremental injections rather than bolus administration 1, 2
• Continuously monitor the patient for early toxicity signs (circumoral numbness, facial tingling, slurred speech, metallic taste) 1, 3

Important Clinical Caveats

Concentration Considerations

• 2% lignocaine (20 mg/mL) should be used cautiously for infiltration 6
• More dilute solutions (0.4-0.5%) allow safer use of higher total volumes when extensive infiltration is needed 6
• The 2% concentration is appropriate for smaller volume infiltrations where the total dose remains within safe limits 6

Site-Specific Factors

• Regional blood flow significantly affects absorption rates 7
• Areas with high vascularity (face, scalp, highly vascular tissues) require dose reduction due to faster systemic absorption 7, 8
• Well-vascularized sites may absorb lignocaine more rapidly, increasing toxicity risk even at standard doses 7

Cardiovascular Considerations

• When adrenaline is added, expect transient increases in heart rate and blood pressure 5
• For patients with cardiac disease, consider using 1:200,000 adrenaline concentration instead of 1:100,000 to minimize cardiovascular effects 5
• The cardiovascular effects are typically short-lived but should be monitored 5

Special Populations Requiring Dose Reduction

Reduce doses by 30-50% in the following situations: 2, 8

• Elderly or debilitated patients 2
• Patients with cardiac disease 2, 8
• Patients with hepatic dysfunction (reduced clearance) 8
• Patients with renal disease 8
• Pediatric patients (maximum 1.5-2.0 mg/kg without adrenaline; 3.0-4.5 mg/kg with adrenaline) 1, 3

Multistage Procedures

For procedures requiring multiple injections over time (e.g., Mohs surgery): 1, 3

• Maximum of 500 mg lignocaine delivered over several hours is acceptable 1, 3
• Allow at least 90 minutes between repeat dosing for continuous techniques 2