Desflurane

Desflurane

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Clinical data
ATC code	N01AB07 (WHO)
Pharmacokinetic data
Metabolism	Not metabolized
Elimination half-life	Elimination dependent on minute ventilation
Identifiers
IUPAC name 2-(difluoromethoxy)-1,1,1,2-tetrafluoro-ethane
CAS Number	57041-67-5
PubChem CID	42113
DrugBank	APRD00907
E number	{{#property:P628}}
ECHA InfoCard	{{#property:P2566}}
Chemical and physical data
Formula	C3H2F6O
Molar mass	168.038 g/mol

Desflurane (2-(difluoromethoxy)-1,1,1,2-tetrafluoro-ethane) is a highly fluorinated methyl ethyl ether used for maintenance of general anaesthesia. Together with sevoflurane, it is gradually replacing isoflurane for human use, except in the third world where its high cost precludes its use. It has the most rapid onset and offset of the volatile anaesthetic drugs used for general anaesthesia due to its low solubility in blood.

The major drawbacks of desflurane are its low potency, its pungency and its high cost. It may cause tachycardia and airway irritability when administered at concentrations greater than 10 vol%. Due to this airway irritability, Desflurane is infrequently used to induce anesthesia via inhalation techniques.

Though it vaporises very readily, it is a liquid at room temperature. Anaesthetic machines are fitted with a specialized anaesthetic vaporiser unit that heats liquid desflurane to a constant temperature. This enables the agent to be available at a constant vapor pressure, negating the effects that fluctuating ambient temperatures would otherwise have on its concentration imparted into the fresh gas flow of the anesthesia machine.

Desflurane, along with enflurane and to a lesser extent isoflurane, has been shown to react with the carbon dioxide absorbant in anesthesia circuits to produce detectable levels of carbon monoxide through degradation of the anesthetic agent. Baralyme appears less prone to cause this degradation than soda lime. Dry conditions in the carbon dioxide absorbant are conducive to this phenomenon, such as those resulting from high fresh gas flows.

Physical properties

Boiling point :	23.5 °C	(at 1 atm)
Density :	1.465 g/cm³	(at 20 °C)
Molecular Weight :	168
Vapor pressure:	88.5 kPa	672 mmHg	(at 20 °C)
	107 kPa	804 mmHg	(at 24 °C)
Blood:Gas partition coefficient :	0.42
Oil:Gas partition coefficient :	19
MAC :	6 vol %

References

Book references

• Eger, Eisenkraft, Weiskopf. The Pharmacology of Inhaled Anesthetics. 2003.
• Rang, Dale, Ritter, Moore. Pharmacology 5th Edition. 2003.