Methoxyflurane

Methoxyflurane
Clinical data
Trade names	Penthrane, Metofane, Penthrox, Penthrop, others
Other names	2,2-dichloro-1,1-difluoroethyl methyl ether
AHFS/Drugs.com	Consumer Drug Information
Pregnancy; category	AU: C; ;
Routes of; administration	Inhaled
Drug class	Volatile anesthetic
ATC code	N02BG09 (WHO) ;
Legal status
Legal status	AU: S4 (Prescription only); BR: Class C1 (Other controlled substances); CA: ℞-only; EU: Rx-only;
Pharmacokinetic data
Metabolism	70%
Onset of action	Rapid
Duration of action	Several minutes
Identifiers
	IUPAC name 2,2-dichloro-1,1-difluoro-1-methoxyethane;
CAS Number	76-38-0 ;
PubChem CID	4116;
DrugBank	DB01028 ;
ChemSpider	3973 ;
UNII	30905R8O7B;
KEGG	D00544 ;
ChEBI	CHEBI:6843 ;
ChEMBL	ChEMBL1341 ;
CompTox Dashboard (EPA)	DTXSID7025556 ;
ECHA InfoCard	100.000.870
Chemical and physical data
Formula	C3H4Cl2F2O
Molar mass	164.96 g·mol−1
3D model (JSmol)	Interactive image;
	SMILES ClC(Cl)C(F)(F)OC;
	InChI InChI=1S/C3H4Cl2F2O/c1-8-3(6,7)2(4)5/h2H,1H3 ; Key:RFKMCNOHBTXSMU-UHFFFAOYSA-N ;
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Methoxyflurane, sold under the brand name Penthrox among others, is an inhaled medication primarily used to reduce pain following trauma.^[5]^[6] It may also be used for short episodes of pain as a result of medical procedures.^[4] Onset of pain relief is rapid and of a short duration.^[4] Use is only recommended with direct medical supervision.^[5]

Common side effects include anxiety, headache, sleepiness, cough, and nausea.^[5] Serious side effects may include kidney problems, liver problems, low blood pressure, and malignant hyperthermia.^[5]^[4] It is unclear if it is safe in either pregnancy or breastfeeding.^[5] It is only recommended in those who have a normal level of consciousness and stable blood pressure and heart rate.^[4] It is classified as a volatile anaesthetic.^[4]

It was first made in 1948 by William T. Miller and came into medical use in the 1960s.^[7] It was used as a general anesthetic from its introduction in 1960 until the late 1970s.^[8] In 1999, the manufacturer discontinued methoxyflurane in the United States, and in 2005 the Food and Drug Administration withdrew it from the market.^[8] It is still used in New Zealand, Australia, Ireland, and the United Kingdom for pain.^[9]^[4]^[10]^[5]^[11]

^ Anvisa (2023-03-31). "RDC Nº 784 - Listas de Substâncias Entorpecentes, Psicotrópicas, Precursoras e Outras sob Controle Especial" [Collegiate Board Resolution No. 784 - Lists of Narcotic, Psychotropic, Precursor, and Other Substances under Special Control] (in Brazilian Portuguese). Diário Oficial da União (published 2023-04-04). Archived from the original on 2023-08-03. Retrieved 2023-08-16.
^ "Search Page - Drug and Health Product Register". 23 October 2014.
^ "List of nationally authorised medicinal products : Active substance: methoxyflurane : Procedure no. PSUSA/00010484/202005" (PDF). Ema.europa.eu. Retrieved 2022-03-12.
^ ^a ^b ^c ^d ^e ^f ^g ^h National Prescribing Service (2010). "Methoxyflurane (Penthrox) for analgesia (doctor's bag listing)". NPS RADAR. Canberra, Australia: National Prescribing Service, Department of Health and Ageing. Archived from the original on 2011-07-27. Retrieved 2011-06-12.
^ ^a ^b ^c ^d ^e ^f British national formulary : BNF 76 (76 ed.). Pharmaceutical Press. 2018. pp. X. ISBN 9780857113382.
^ Jephcott C, Grummet J, Nguyen N, Spruyt O (May 2018). "A review of the safety and efficacy of inhaled methoxyflurane as an analgesic for outpatient procedures". British Journal of Anaesthesia. 120 (5): 1040–1048. doi:10.1016/j.bja.2018.01.011. PMID 29661381.
^ Hardman JG, Hopkins PM, Struys MM (2017). Oxford Textbook of Anaesthesia. Oxford University Press. p. 553. ISBN 9780199642045.
^ ^a ^b Mazze RI (October 2006). "Methoxyflurane revisited: tale of an anesthetic from cradle to grave". Anesthesiology. 105 (4): 843–846. doi:10.1097/00000542-200610000-00031. PMID 17006084.
^ "NZ Medsafe Datasheet" (PDF). Medsafe.govt.nz. Retrieved 12 March 2022.
^ PHECC Clinical Practice Guidelines (6 ed.). Pre-Hospital Emergency Care Council. March 2017. p. 100. ISBN 978-0-9929363-6-5. Retrieved 7 January 2019.
^ Porter KM, Siddiqui MK, Sharma I, Dickerson S, Eberhardt A (2018). "Management of trauma pain in the emergency setting: low-dose methoxyflurane or nitrous oxide? A systematic review and indirect treatment comparison". Journal of Pain Research. 11: 11–21. doi:10.2147/JPR.S150600. PMC 5741984. PMID 29302193.

[1] Anvisa (2023-03-31). "RDC Nº 784 - Listas de Substâncias Entorpecentes, Psicotrópicas, Precursoras e Outras sob Controle Especial" [Collegiate Board Resolution No. 784 - Lists of Narcotic, Psychotropic, Precursor, and Other Substances under Special Control] (in Brazilian Portuguese). Diário Oficial da União (published 2023-04-04). Archived from the original on 2023-08-03. Retrieved 2023-08-16.

[2] "Search Page - Drug and Health Product Register". 23 October 2014.

[3] "List of nationally authorised medicinal products : Active substance: methoxyflurane : Procedure no. PSUSA/00010484/202005" (PDF). Ema.europa.eu. Retrieved 2022-03-12.

[NPS2010-4] ^ ^a ^b ^c ^d ^e ^f ^g ^h National Prescribing Service (2010). "Methoxyflurane (Penthrox) for analgesia (doctor's bag listing)". NPS RADAR. Canberra, Australia: National Prescribing Service, Department of Health and Ageing. Archived from the original on 2011-07-27. Retrieved 2011-06-12.

[BNF76-5] ^ ^a ^b ^c ^d ^e ^f British national formulary : BNF 76 (76 ed.). Pharmaceutical Press. 2018. pp. X. ISBN 9780857113382.

[Jep2018-6] Jephcott C, Grummet J, Nguyen N, Spruyt O (May 2018). "A review of the safety and efficacy of inhaled methoxyflurane as an analgesic for outpatient procedures". British Journal of Anaesthesia. 120 (5): 1040–1048. doi:10.1016/j.bja.2018.01.011. PMID 29661381.

[Hard2017-7] Hardman JG, Hopkins PM, Struys MM (2017). Oxford Textbook of Anaesthesia. Oxford University Press. p. 553. ISBN 9780199642045.

[Maz2006-8] Mazze RI (October 2006). "Methoxyflurane revisited: tale of an anesthetic from cradle to grave". Anesthesiology. 105 (4): 843–846. doi:10.1097/00000542-200610000-00031. PMID 17006084.

[9] "NZ Medsafe Datasheet" (PDF). Medsafe.govt.nz. Retrieved 12 March 2022.

[10] PHECC Clinical Practice Guidelines (6 ed.). Pre-Hospital Emergency Care Council. March 2017. p. 100. ISBN 978-0-9929363-6-5. Retrieved 7 January 2019.

[11] Porter KM, Siddiqui MK, Sharma I, Dickerson S, Eberhardt A (2018). "Management of trauma pain in the emergency setting: low-dose methoxyflurane or nitrous oxide? A systematic review and indirect treatment comparison". Journal of Pain Research. 11: 11–21. doi:10.2147/JPR.S150600. PMC 5741984. PMID 29302193.

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