“The main clinical role of lidocaine hydrochloride is as a local anesthetic, but the pharmacological effects of lidocaine will vary with the dose of the drug. After lidocaine is absorbed from the blood or administered intravenously, it can affect the central nervous system. There will be obvious two-way effects of excitation and inhibition, and there may be no precursor excitation. When the blood drug concentration is low, labor pain, drowsiness, and pain threshold increase may occur.