Tetracaine hydrochloride is a long-acting ester local anesthetic. Its action characteristics are: strong penetration of mucous membranes, suitable for surface anesthesia, and commonly used in ophthalmology. After injection, the anesthetic effect appears slowly (about 10 minutes), and the metabolism after absorption is also slow. The local anesthesia time is as long as 3IJ, H,-J. About. After the instillation of Tetracaine hydrochloride into the eye, there is no adverse reaction such as vasoconstriction, mydriasis, and corneal damage. The local anesthetic effect and toxicity are about 10 times greater than procaine. It is mainly used for surface anesthesia of the eye, nose, and throat mucosa, and is rarely used for conduction anesthesia and epidural anesthesia. Due to its high toxicity, it is generally not used for infiltration anesthesia.