pharmacological mechanism 

Blocking voltage dependent sodium channels leads to conduction block and produces anesthetic effects.

Local anesthetics have lipophilic effects, and non dissociative type is a necessary condition for nerve penetration. After nerve penetration, they must be converted into dissociative charged cations to exert their effects. The proportion of dissociative/non dissociative types of different local anesthetics varies.

Pharmacology and Application

The local anesthetic effect is stronger than procaine and 10 times greater than procaine. The toxicity is also high, 10-12 times greater than procaine. It can penetrate the mucosa and is mainly used for mucosal anesthesia. The effect is rapid and takes effect within 1-3 minutes. Maintain for 2-3 hours. Ophthalmic use of 0.5% to 1% solution, with no serious adverse reactions such as corneal injury. The nasal and throat department should use a 1% to 2% solution, with a total volume not exceeding 20ml. When applied, 1 drop of 0.1% adrenaline hydrochloride solution should be added every 3ml. 0.025% to 0.03% solution is used for infiltration anesthesia, and 0.1% to 0.3% solution is used for nerve conduction block. During spinal anesthesia, mix 10-15 mg with cerebrospinal fluid and inject. A 0.15% to 0.3% solution is used for epidural anesthesia, with a maximum concentration of 0.3% when combined with lidocaine. Due to its high toxicity, infiltration anesthesia is generally not performed.

Extreme dose: infiltration anesthesia, nerve conduction block, 0.1g once.

Usage and dosage

Epidural block: The commonly used concentration is 0.15-0.3% solution, combined with lidocaine hydrochloride, with a maximum concentration of 0.3%. The commonly used dose is 40-50mg at a time, with a maximum dose of 80mg.

Subarachnoid block: commonly used mixture (1ml of 1% lidocaine hydrochloride mixed with 1ml of 10% glucose injection and 1ml of 3% ephedrine hydrochloride), with a common dose of 10mg, 15mg as the limit, and 20mg as the maximum dose.

Nerve conduction block: The commonly used concentration is 0.1% to 0.2%, with a single dose of 40-50 mg and a maximum dose of 100 mg.

Mucosal surface anesthesia: commonly used concentration 1%, ophthalmology uses 1% isotonic solution, otolaryngology uses 1-2% solution, with a one-time limit of 40 mg.