Isoflurane Flashcards
Please note that the drug card information is for Educational Use ONLY, and the source is from Carrie Bowman's glossary of drug cards permitted by use of Georgetown NAP students. No permission is given to use these cards for anything other than as a study resource for our program.
What is the trade name for Isoflurane?
Forane, USP
What drug class is Isoflurane in?
General Inhalational Anesthetic
What is Isoflurane (chemically speaking)?
Halogenated methyl ethyl ether
What is the primary use of Isoflurane?
Induction and maintenance of GA
What makes Isoflurane less useful as an induction agent?
Pungent Odor
What is the MOA of Isoflurane?
Current predominant theory is that target proteins (most likely ion channels/and or receptors) are the site of action of the inhaled anesthetics. Separate sites of action for the loss of consciousness and immobility have been preposed
What are the pharmacokinetics of Isoflurane?
- Small, lipid-soluble molecules that readily cross alveolar membranes
- Isoflurane is specifically a ventilation-limited anesthetic
What does it mean that Isoflurane is a ventilation-limited anesthetic?
It has a high rate of uptake into the bloodstream that prevents the alveolar partial pressure from rising rapidly. Physiologic or pathologic changes that act to increase the rate of rise of the alveolar partial pressure will speed induction
How is Isoflurane metabolized?
- metabolized only slightly (0.2-2%!)
- deflurinated much less than other halogenated agents
- oxidatively metabolized by the liver CYP450 enzymes to form acetylated liver protein adducts
What are the acetylated liver protein adducts capable of?
evoking an antibody response that could occur after exposure to Isoflurane (aka Halothane Hepatitis!)
What can acetylated liver protein adducts cause?
Massive Hepatotoxicity
What is the partial pressure of Isoflurane?
240mmHg at 20C
What is Isoflurane’s Blood/Gas coefficient and Oil/Gas partition coefficient?
1.4 (intermediate solubility in blood)
91 (solubility in fat)
How is isoflurane eliminated?
Both ventilation and metabolism; but the lungs mostly eliminate isoflurane (only 0.17% of iso is excreted in the urine as urinary metabolites)
What is the volume of distribution for Iso?
The time constant of iso for equilibration of tissue with arterial partial pressure is 2.1 minutes into the vessel-rich group (CNS and visceral organs), 88 minutes into the muscle group (muscle and skin), and 2039 min into the fat group