GasGasGas - The FRCA Primary Exam Podcast GasGasGas - Isoflurane
Oct 31, 2025
Discover the fascinating world of isoflurane, an underrated volatile anesthetic. Learn about its unique chemical properties and how it compares to its flashier counterparts. The discussion dives into its mechanisms, including GABA potentiation, and explores its cardiovascular and respiratory effects. Dr. Gas Lurks also highlights dosage concerns and how Dalton's law relates to anesthetic use. Plus, get insights into isoflurane's pharmacokinetics and safety profile. Perfect for anyone keen on mastering the art of anesthesia!
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Isoflurane Chemistry Explains Low Metabolism
- Isoflurane is a halogenated methyl ethyl ether and a structural isomer of n‑fluorane.
- Its three terminal fluorines make it minimally metabolised by the liver and chemically stable.
Memorise Isoflurane Core Numbers
- Remember key physical constants: boiling point 48.5°C and saturated vapour pressure ≈32 kPa at 20°C.
- Use MAC 1.17 (aim ET ~1.2%) and blood-gas solubility 1.4 to guide dosing and expectations.
Oil Solubility Drives Potency
- Oil-gas coefficient (98) means isoflurane is potent compared with desflurane (25).
- Higher oil solubility explains lower MAC and greater potency versus less soluble volatiles.