Local anesthetic overdose primarily affects which system?

Local anesthetic overdose primarily affects the central nervous system (CNS). This is due to the ability of local anesthetics to bind to sodium channels within neuronal membranes, leading to alterations in neuronal excitability. When an overdose occurs, symptoms can manifest as central nervous system toxicity, which may include signs of stimulation such as tinnitus, muscle twitching, seizures, and, at higher doses, can progress to CNS depression characterized by respiratory arrest or coma.

While local anesthetics can have effects on other systems, such as causing cardiovascular symptoms due to their action on cardiac tissues or impacting the respiratory system indirectly through changes in CNS function, the primary and most concerning effects occur within the central nervous system. The skeletal and lymphatic systems are not directly affected by local anesthetics, making them less relevant in the context of overdose scenarios.