A local anesthetic (LA) is a drug that causes reversible local anesthesia, generally for the aim of having a local analgesic effect, that is, inducing absence of pain sensation, although other local senses are often affected as well. Also, when it is used on specific nerve pathways (nerve block), paralysis (loss of muscle power) can be achieved as well.
Clinical local anesthetics belong to one of two classes: aminoamide and aminoester local anesthetics. Synthetic local anesthetics are structurally related to cocaine. They differ from cocaine mainly in that they have no abuse potential and do not act on the sympathoadrenergic system, i.e. they do not produce hypertension or local vasoconstriction, with the exception of Ropivacaine and Mepivacaine that do produce weak vasoconstriction.
Local anesthetics vary in their pharmacological properties and they are used in various techniques of local anesthesia such as:
- Topical anesthesia (surface)
- Infiltration
- Plexus block
- Epidural (extradural) block
- Spinal anesthesia (subarachnoid block)
The local anesthetic lidocaine (lignocaine) is also used as a Class Ib antiarrhythmic drug.
Read more about Local Anesthetic: Mechanism of Action, Techniques, Local Anesthetics in Clinical Use, Naturally Derived Local Anesthetics, History
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