Lidocaine toxicity misinterpreted as a stroke

For more than 50 years lidocaine has been used to treat ventricular arrhythmias. Neurologic dysfunction, manifested as a stroke, occurred acutely in an 87-year-old woman after she had been administered repeated doses of lidocaine, a lidocaine infusion, then an intravenous amiodarone infusion for ventricular tachycardia. This was ultimately diagnosed as lidocaine toxicity with a serum lidocaine level of 7.9 mg/L (1.5-6.0 mg/L). We discuss lidocaine toxicity and risk factors leading to its development, which include particularly hepatic dysfunction, cardiac dysfunction, advanced age and other drug administration.