Local Anesthetic Agents: Classification and Properties

Local Anesthetic Agents

Classification

• Esters:
  • Procaine (Novocain)
  • Tetracaine (Amethocaine)
  • Benzocaine
  • Chloroprocaine
• Amides:
  • Lidocaine (Xylocaine)
  • Mepivacaine (Carbocaine)
  • Prilocaine (Citanest)
  • Bupivacaine (Marcaine)
  • Ropivacaine (Naropin)

Mechanism of Action

• Block the generation and propagation of nerve impulses by:
  • Inhibiting the sodium channel
  • Reducing the influx of sodium ions
  • Decreasing the excitability of the nerve

Properties

• Potency: The ability to produce anesthesia
• Duration: The length of time the anesthetic remains effective
• Onset: The time it takes for the anesthetic to take effect
• Diffusion: The ability of the anesthetic to spread through tissue

Effects on Nerve Fibers

• A-delta fibers: First affected, responsible for sharp pain and temperature sensation
• A-beta fibers: Affected next, responsible for touch and pressure sensation
• C fibers: Last affected, responsible for dull pain and temperature sensation

Clinical Considerations

• Dose: The amount of anesthetic required to produce anesthesia
• Concentration: The strength of the anesthetic solution
• Volume: The amount of anesthetic solution used
• Speed of injection: Affects the onset and quality of anesthesia

Learn about the different types of local anesthetic agents, their mechanism of action, properties, and effects on nerve fibers. Test your knowledge on the classification, potency, duration, and clinical considerations of local anesthetics.