Lidocaine toxicity typically manifests as central nervous system symptoms such as tongue numbness, tinnitus, visual disturbances, seizure, and cardiovascular depression.
The maximum dose of lidocaine without epinephrine is 5 mg/kg (4.5 mg/kg, to be exact) and 7 mg/kg for lidocaine with epinephrine. The total maxiumum dose is 300 mg.
