General Anesthetics

General anesthetics are divided into inhalational and intravenous types.

1. INHALATIONAL ANESTHETICS

Further classified into:

• Gases
  • Example: Nitrous oxide (N₂O) (the only commonly used gas).
• Volatile Liquids
  • Contain fluorine (Halogenated compounds).
  • Examples:
    • Halothane
    • Isoflurane
    • Sevoflurane
    • Desflurane
  • Mnemonic to remember: “DISH” (Desflurane, Isoflurane, Sevoflurane, Halothane).

2. INTRAVENOUS ANESTHETICS

Subdivided based on duration of action:

• Ultrashort-acting (Induction agents):
  • Thiopental (Barbiturate)
  • Propofol
  • Etomidate
  • Ketamine (Dissociative anesthetic).
• Slower acting:
  • Benzodiazepines (e.g., Midazolam for sedation).

Key Notes

• Inhalational agents are used for maintenance of anesthesia.
• IV agents are preferred for rapid induction.
• Nitrous oxide is weak (low MAC) and often combined with other agents.
• Halogenated volatile liquids (e.g., Sevoflurane) are potent and fluorinated.