Local Anesthetics

Local anesthetics

Local anesthetics are compounds that prevent the generation and the conduction of nerve impulses near to the site of application or injection, resulting in a loss of sensation which is reversible.
Local anesthetics are most often used to produce a loss of pain without loss of consciousness; thus are also referred to as local analgesics.
Local Anesthetics

Ideal properties

  • Should be non-irritating.
  • Should have low toxicity.
  • Effective oral as well as intravenous.
  • Rapid onset of action and short duration of action.

Types of local anesthetics

Topical- Applied on the mucous membrane.
Infiltration- Injected into tissues.
Field block- Injected into the subcutaneous layer.
Nerve block- Injected into the peripheral nerve.
Spinal- Injected into CSF of lumber region.
Intravenous- Injected into nerve trunks and endings.
Epidural- Injected into epidural space.

Classification

Natural

Cocaine, Hexylcaine, Cyclomethylcaine

Synthetic nitrogenous agent

p-aminobenzoic acid derivatives- Procaine,  Benzocaine, Butamben, Butacaine
Anilides- Mepivacaine, Lidocaine, Bupivacaine
Quinoline derivatives- Cinchocaine, Dimethylisoquine

Synthetic non-nitrogenous agent

Benzoyl alcohol, Propanediol

Miscellaneous agent

Phenol