local anesthetics presentation anesthesia complete guide

Local anesthesia prevents pain during procedures by blocking nerves from transmitting pain signals to the brain. The effects of local anesthetic are short-lived, so healthcare teams primarily use it for minor outpatient procedures.

Anesthetists or doctors only apply local anesthetic to the part of the body that the medical procedure involves.

People may also receive sedative drugs, which reduce stress levels and promote calmness. Together, anesthesia and sedation enable the doctor or surgeon to carry out the procedure without causing pain or distress.

In cases where surgeons need to perform more invasive or long lasting procedures, anesthetists will typically administer a regional or general anesthetic instead.

1. Local anesthetic (LA) are drugs that block nerve conduction when applied locally to nerve tissue in appropriate concentrations. Their action is completely reversible. They act on every type of nerve fiber They can cause both sensory and motor paralysis in the innervated area. They act on axons, cell body, dendrites, synapses and other excitable membranes that utilize sodium channels as the primary means of action potential generation.

2. Cocaine was the first agent to be isolated by Niemann in 1860. In spite of its addiction potential, cocaine was used for 30 years as a surface anesthetic. In an effort made to improve the properties of cocaine, procaine was synthesized in 1905. It ruled the field for the next 50 years. In 1943, lignocaine was synthesized by Lofgren and it continues to di dominate the field till today.

3. Injectable Short-acting: Procaine, chloroprocaine Intermediate-acting: Lignocaine, prilocaine Long-acting: Tetracaine (amethocaine), bupivacaine, dibucaine, ropivacaine , etidocaine Surface anaesthetics Lignocaine,cocaine,tetracaine,benzocaine,oxethazaine , Ropivacaine

4. Est e rs Est e rs Cocaine Procaine Tetracaine Benzocaine Chloroprocaine Lignocaine (lidocaine)
Mepivacaine Bupivacaine
Ropivacaine Etidocaine
Prilocaine Articaine Esters Amides Note:
Esters
Single ‘i’ in all names Note:
Amides
Double ‘ i ’ in all names BASED ON CHEMICAL STRUCTURE

5. USES OF LOCAL ANESTHETICS Surface anesthesia ( anesthesia of mucous membrane of the eye, nose, mouth, tracheobronchial tree, esophagus )
Infiltration anesthesia Field block (subcutaneous injection of LA)
Nerve block
Spinal anesthesia Epidural anesthesia

6. MECHANISM OF ACTION OF LOCAL ANESTHETICS