What is a common side effect of local anesthetics when used in high doses?

When local anesthetics are used in high doses, a notable and significant side effect is seizures due to central nervous system (CNS) toxicity. Local anesthetics work by blocking sodium channels, which inhibit nerve conduction. However, at elevated doses, they can also affect the CNS, leading to excitatory symptoms such as seizures. This toxicity is a critical concern in clinical settings, as it can happen rapidly depending on the pharmacokinetics of the specific agent used and the overall dosage administered. Early recognition of CNS toxicity is essential for timely intervention and management.

Other side effects like localized swelling at the injection site, increased heart rate, and prolonged sedation can occur; however, they are less common and generally associated with specific circumstances rather than a direct result of using high doses of local anesthetics. Seizures represent a serious complication and highlight the importance of appropriate dosing and monitoring during the use of local anesthetics.