A Rare Case of Euphoria Caused by Lidocaine After an Erector Spinae Plane Block: A Case Report

Lidocaine is a cost-effective drug that is widely used for local and regional anesthesia. However, central nervous system (CNS) toxicity can occur when lidocaine is administered above the maximum recommended dose (approximately 4.5 mg/kg) or if lidocaine is injected intravascularly rather than administered locally. Systemic toxicity by lidocaine has been reported in several studies. However, psychotic reactions due to lidocaine have been rarely reported; furthermore, reports of lidocaine-related euphoria are very rare. We report a very rare case of euphoria caused by CNS toxicity that occurred during the local administration of lidocaine at the therapeutic dose. Therefore, anesthesiologists should be aware of the severe side effects of local anesthetics despite administering the appropriate dosage at the appropriate location. Future studies should investigate pharmacokinetics to determine the safety profile of local anesthetics.