Halothane

Structural formula
	Structural formula without stereochemistry
General
Non-proprietary name	Halothane
other names	2-bromo-2-chloro-1,1,1-trifluoroethane
Molecular formula	C 2 HBrClF 3
Brief description	colorless, volatile liquid with a sweet odor
External identifiers / databases
EC number	205-796-5
ECHA InfoCard	100.005.270
PubChem	3562
DrugBank	DB01159
Wikidata	Q32921
Drug information
ATC code	N01 AB01
Drug class	narcotic
properties
Molar mass	197.39 g mol −1
Physical state	liquid
density	1.871 g cm −3
Melting point	−118 ° C
boiling point	50.2 ° C
Vapor pressure	324 h Pa (20 ° C)
solubility	heavy in water (3.7 g l −1 at 24 ° C); miscible with petroleum ether ;
Refractive index	1.3697
safety instructions
	Please note the exemption from the labeling requirement for drugs, medical devices, cosmetics, food and animal feed
H and P phrases	H: 315-318-335-360
	P: 201-261-280-305 + 351 + 338-308 + 313
MAK	DFG : 41 mg m −3 ; Switzerland: 5 ml m −3 or 40 mg m −3 ;
Toxicological data	29,000 ppm ( LC 50 , rat , inh. )
Global warming potential	50 (based on 100 years)
Thermodynamic properties
ΔH f 0	−720.0 kJ / mol
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . Refractive index: Na-D line , 20 ° C

Halothane is a halogenated hydrocarbon that was synthesized by Charles Suckling in 1951 for Imperial Chemical Industries . Since its first clinical application under the trade name as Fluothane on January 20, 1956 by Michael Johnstone in Manchester , it has been used as an inhalation anesthetic which is administered via the airways . In Europe and the USA, halothane has largely been replaced by the newer anesthetics isoflurane , sevoflurane and desflurane . See corridors .

The use of halothane can lead to malignant hyperthermia .

Extraction and presentation

The industrial synthesis of halothane takes place starting from trichlorethylene , which reacts with hydrogen fluoride in the presence of antimony trichloride at 130 ° C to form 2-chloro-1,1,1-trifluoroethane . This then reacts with bromine at 450 ° C to form halothane.

properties

Desired properties

Halothane is a colorless liquid with a sweet odor. Since halothane is very sensitive to light, it is usually stored in brown bottles. Halothane is easily soluble in blood and fat. Halothane flows in and out of the blood very quickly, which is why it is particularly suitable as an anesthetic . In addition, it does not form explosive mixtures, can be combined with nitrous oxide (N ₂ O) (dose reduction possible) and is an extremely potent inhalation anesthetic. The therapeutic range is around 0.5–1% atm. Alveolar Concentration.

Undesirable properties

Like almost all narcotics, halothane has a narrow therapeutic index and causes a dose-dependent drop in blood pressure. Heart rate stays the same or decreases with halothane. Halothane also sensitizes the myocardium to catecholamines , which is why tachycardias can also occur. When metabolized (around 15–20%) in the liver, bromide ions are released, which in large quantities are toxic, can trigger allergies and suppress the immune system. In rare cases (1: 10000) halothane hepatitis develops (as an allergic reaction), which is why it is recommended that patients be anesthetized with halothane only every three months. It should be noted here that the staff, unlike the patient, can be very stressful.

Halothane is becoming less and less important as a narcotic because halogenated ethers such as enflurane , isoflurane or sevoflurane have significantly better pharmacological properties.

The lifetime in the atmosphere is one year, the global warming potential (GWP) 50 and the emissions are 250 tons per year.

Trade names

Fluothane (D, aH), Narcotan (D, aH), Halothane BP (CH, aH)

literature

Erich Kirchner (Ed.): 20 years of Fluothane. Springer, Berlin 1978 (= anesthesiology and intensive care medicine. Volume 109), ISBN 978-3-540-08602-4 .
Max S. Sadove, Vernon E. Wallace: Halothane. Blackwell Scientific Publications, Oxford 1962.

Individual evidence

↑ ^a ^b ^c ^d ^e ^f ^g Entry on 2-bromo-2-chloro-1,1,1-trifluoroethane in the GESTIS substance database of the IFA , accessed on January 9, 2019(JavaScript required) .
↑ ^a ^b ^c Entry on halothane in the ChemIDplus database of the United States National Library of Medicine (NLM) .
↑ ^a ^b Entry on Halothane. In: Römpp Online . Georg Thieme Verlag, accessed on December 25, 2014.
↑ Swiss Accident Insurance Fund (Suva): Limit values - current MAK and BAT values (search for 151-67-7 or halothane ), accessed on November 2, 2015.
↑ G. Myhre, D. Shindell et al .: Climate Change 2013: The Physical Science Basis . Working Group I contribution to the IPCC Fifth Assessment Report. Ed .: Intergovernmental Panel on Climate Change . 2013, Chapter 8: Anthropogenic and Natural Radiative Forcing, pp. 24-39; Table 8.SM.16 ( PDF ).
↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Standard Thermodynamic Properties of Chemical Substances, pp. 5-21.
↑ M. Johnstone: The human cardiovascular response to fluothane anesthesia. In: British Journal of Anesthesiology. Volume 28, No. 9, pp. 392-410.
↑ Suckling et al: PROCESS FOR THE PREPARATION OF 1,1,1-TRIFLUORO-2-BROMO-2-CHLOROETHANE. US patent 2921098, granted January 1960, assigned to Imperial Chemical Industries.
↑ HH Frey, W. Löscher: Textbook of pharmacology and toxicology for veterinary medicine. 2nd Edition. Enke Verlag, 2007, ISBN 3-8304-1070-0 ( limited preview in Google book search).
↑ Reinhard Larsen: Anesthesia and intensive medicine in cardiac, thoracic and vascular surgery. (1st edition 1986) 5th edition. Springer, Berlin / Heidelberg / New York et al. 1999, ISBN 3-540-65024-5 , pp. 3-6; here: p. 3 f.
↑ Martin K. Vollmer, Tae Siek Rhee, Matt Rigby, Doris Hofstetter, Matthias Hill, Fabian Schoenenberger, Stefan Reimann: Modern inhalation anesthetics: Potent greenhouse gases in the global atmosphere . In: Geophysical Research Letters . 42, No. 5, 2015, p. 1606. doi : 10.1002 / 2014GL062785 .

[GESTIS-1] ↑ ^a ^b ^c ^d ^e ^f ^g Entry on 2-bromo-2-chloro-1,1,1-trifluoroethane in the GESTIS substance database of the IFA , accessed on January 9, 2019(JavaScript required) .

[ChemIDplus-2] Entry on halothane in the ChemIDplus database of the United States National Library of Medicine (NLM) .

[roempp-3] Entry on Halothane. In: Römpp Online . Georg Thieme Verlag, accessed on December 25, 2014.

[4] Swiss Accident Insurance Fund (Suva): Limit values - current MAK and BAT values (search for 151-67-7 or halothane ), accessed on November 2, 2015.

[5] G. Myhre, D. Shindell et al .: Climate Change 2013: The Physical Science Basis . Working Group I contribution to the IPCC Fifth Assessment Report. Ed .: Intergovernmental Panel on Climate Change . 2013, Chapter 8: Anthropogenic and Natural Radiative Forcing, pp. 24-39; Table 8.SM.16 ( PDF ).

[CRC90_5_21-6] David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Standard Thermodynamic Properties of Chemical Substances, pp. 5-21.

[7] M. Johnstone: The human cardiovascular response to fluothane anesthesia. In: British Journal of Anesthesiology. Volume 28, No. 9, pp. 392-410.

[8] Suckling et al: PROCESS FOR THE PREPARATION OF 1,1,1-TRIFLUORO-2-BROMO-2-CHLOROETHANE. US patent 2921098, granted January 1960, assigned to Imperial Chemical Industries.

[9] HH Frey, W. Löscher: Textbook of pharmacology and toxicology for veterinary medicine. 2nd Edition. Enke Verlag, 2007, ISBN 3-8304-1070-0 ( limited preview in Google book search).

[10] Reinhard Larsen: Anesthesia and intensive medicine in cardiac, thoracic and vascular surgery. (1st edition 1986) 5th edition. Springer, Berlin / Heidelberg / New York et al. 1999, ISBN 3-540-65024-5 , pp. 3-6; here: p. 3 f.

[11] Martin K. Vollmer, Tae Siek Rhee, Matt Rigby, Doris Hofstetter, Matthias Hill, Fabian Schoenenberger, Stefan Reimann: Modern inhalation anesthetics: Potent greenhouse gases in the global atmosphere . In: Geophysical Research Letters . 42, No. 5, 2015, p. 1606. doi : 10.1002 / 2014GL062785 .