Sevoflurane

Sevoflurane

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Systematic (IUPAC) name
1,1,1,3,3,3-hexafluoro-2-(fluoromethoxy)propane
Clinical data
Routes of administration	inhaled
Legal status
Legal status	UK: POM (Prescription only) US: ℞-only
Identifiers
CAS Number	28523-86-6
ATC code	N01AB08 (WHO)
PubChem	CID 5206
DrugBank	APRD00219
Chemical data
Formula	C4H3F7O
Molar mass	200.055 g/mol[[]]

Sevoflurane (2,2,2-trifluoro-1-[trifluoromethyl]ethyl fluoromethyl ether), also called fluoromethyl hexafluoroisopropyl ether, is a sweet-smelling, non-flammable, highly fluorinated methyl isopropyl ether used for induction and maintenance of general anesthesia. Together with desflurane, it is replacing isoflurane and halothane in modern anesthesiology. It is often administered in a mixture of nitrous oxide and oxygen. After desflurane, it is the volatile anesthetic with the fastest onset and offset. Though desflurane has the lowest blood/gas coefficient of the currently used volatile anesthetics, sevoflurane is the preferred agent for mask induction due to its lesser irritation to mucous membranes.

First reports of sevoflurane appeared in the literature in 1971. The agent was developed by scientists at Baxter Laboratories. It was introduced into clinical practice initially in Japan in 1990. The rights for sevoflurane in the US and other countries are held by Abbott Laboratories.

Sevoflurane forms at least two degradation products, Compound A [fluoromethyl-2,2-difluoro-1-(trifluoromethyl)vinyl ether] and Compound B [1,1,1,3,3-pentafluoro-2-(fluoromethoxy)-3-methoxypropane], on contact with the soda lime in a rebreathing apparatus, which absorbs exhaled carbon dioxide, especially at higher temperatures and when the soda lime is desiccated. Compound A has been shown to cause renal necrosis in rats. In humans, direct histological evidence of renal toxicity has not been demonstrated, although there is dose-related proteinuria, glycosuria and enzymuria. During low-flow anaesthesia, when the lower fresh gas flow leads to decreased flushing of the circuit and increased temperature of the soda lime, Compound A may build up to clinically significant levels, although there have never been any reports of adverse events in humans. As a result, sevoflurane is sometimes administered with a minimum fresh gas flow of 2 liters per minute, making it a relatively expensive choice for maintaining general anesthesia. Only two countries currently maintain mandatory minimum flow rates of 2L/min; Canada and Australia. Recent generic competition in select markets has also significantly lowered the unit cost of Sevoflurane, making it more cost effective.

The U.S. Environmental Protection Agency‎ (EPA) has classified sevoflurane as a greenhouse gas, with a global warming potential of 345. One tonne of sevoflurane emitted is equivalent to 345 tonnes of carbon dioxide in the atmosphere.

Sevoflurane has been implicated in neuronal degeneration in infant mice. This activity is thought to occur via blockade of NMDA receptors or hyperactivity of GABA neurotransmission. In this study the researchers showed that exposure of infant mice to inhaled sevoflurane resulted in learning deficits and abnormal social behaviour

Physical properties

Boiling point:	58.6 °C	(at 101.325 kPa)
Density:	1.517–1.522 g/cm³	(at 20 °C)
MAC :	2 vol %
Molecular Weight:	200 u
Vapor pressure:	157 mmHg (20.9 kPa)	(at 20 °C)
	197 mmHg (26.3 kPa)	(at 25 °C)
	317 mmHg (42.3 kPa)	(at 36 °C)
Blood:Gas Partition Coefficient:	0.68
Oil:Gas Partition Coefficient:	47

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External links

• "Propofol and Sevoflurane Anesthesia". 

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