Determine maximum safe lidocaine dose by weight.
Maximum lidocaine dose is 4.5 mg/kg without epinephrine and 7 mg/kg with epinephrine. A 1% solution contains 10 mg/mL, 2% contains 20 mg/mL. Signs of toxicity include perioral numbness, tinnitus, seizures, and cardiac arrest. Always aspirate before injecting and use the lowest effective dose.