Anesthetic

Question 1

What was the first local anesthetic available?

Answer 1

Cocaine

Question 2

Actions of anethetics

Answer 2

• Reversible blockage of nerve impulse generation and conduction
• Affect sensation of pain & temperature
• Reversibly block voltage-gated sodium channels (as opposed to
  ligand-gated channels)
• Lipophilic properties facilitate passage of the anesthetic into the
  cell to evokes its effect on the ion channel by binding to the
  intracellular side of the receptor

Question 3

Desirable effects of anethetics

Answer 3

• Rapid onset
• Suitable potency
• Adequate duration of action
• Minimal side effects
• Minimal local tissue damage

Question 4

Chemistry and chemical structures of anesthetics

Answer 4

• Lipophilic synthetic aromatic or heterocyclic residue
  
  • Lipophilic ring serves to penetrate nerve membrane; this confers potency
• Intermediate ester or amide linkage
  
  • The type of linkage determines the route of metabolism; longer linkages promote potency
• Weakly basic tertiary amine terminal
  
  • The cationic moiety provides the essential chemistry required to interact with the channel

* Topical anesthetics have a pKa 8-9 which renders them uncharged at
 alkaline pH (vs inflamed tissues), thereby facilitating lipid penetration

• Weakly Basic Aromatic Amines
• Intermediate chain linkage unites a lipophilic aromatic residue with a hydrophilic amino group; longer linkage and lipophilicity enhances potency (receptor site is
  hydrophobic) , duration, and decreases the TI