The maximum safe dose of lignocaine infiltrated for local anaesthesia when combined with adrenaline is:

• A 3 mg/kg
• B 5 mg/kg
• C 7 mg/kg ✓
• D 10 mg/kg

Explanation

Plain lignocaine has a maximum dose of about 4 to 4.5 mg/kg, but when combined with adrenaline the vasoconstriction slows absorption and the ceiling rises to approximately 7 mg/kg. Adrenaline also prolongs anaesthesia and keeps the surgical field dry during facial procedures. Exceeding these limits risks lignocaine toxicity with circumoral numbness, tinnitus, seizures and arrhythmias.

Reference: Malamed's Handbook of Local Anesthesia, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.