Methoxyflurane

Methoxyflurane
Clinical data
Trade namesPenthrox, Penthrane, Metofane, others
Other names2,2-dichloro-1,1-difluoroethyl methyl ether
AHFS/Drugs.comConsumer Drug Information
Pregnancy
category
  • AU: C
Routes of
administration		Inhalation
Drug classVolatile anesthetic
ATC code
Legal status
Legal status
Pharmacokinetic data
Metabolism70%
Onset of actionRapid[4]
Duration of actionSeveral minutes[4]
Identifiers
  • 2,2-dichloro-1,1-difluoro-1-methoxyethane
CAS Number
PubChem CID
DrugBank
ChemSpider
UNII
KEGG
ChEBI
ChEMBL
CompTox Dashboard (EPA)
ECHA InfoCard100.000.870 Edit this at Wikidata
Chemical and physical data
FormulaC3H4Cl2F2O
Molar mass164.96 g·mol−1
3D model (JSmol)
  • ClC(Cl)C(F)(F)OC
  • InChI=1S/C3H4Cl2F2O/c1-8-3(6,7)2(4)5/h2H,1H3 checkY
  • Key:RFKMCNOHBTXSMU-UHFFFAOYSA-N checkY
 ☒NcheckY (what is this?)  (verify)

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]

  1. ^ Anvisa (31 March 2023). "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 4 April 2023). Archived from the original on 3 August 2023. Retrieved 16 August 2023.
  2. ^ "Regulatory Decision Summary for Penthrox". 23 October 2014.
  3. ^ "List of nationally authorised medicinal products : Active substance: methoxyflurane : Procedure no. PSUSA/00010484/202005" (PDF). Ema.europa.eu. Retrieved 12 March 2022.
  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 27 July 2011. Retrieved 12 June 2011.
  5. ^ a b c d e f British national formulary : BNF 76 (76 ed.). Pharmaceutical Press. 2018. pp. X. ISBN 9780857113382.
  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.
  7. ^ Hardman JG, Hopkins PM, Struys MM (2017). Oxford Textbook of Anaesthesia. Oxford University Press. p. 553. ISBN 9780199642045.
  8. ^ 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.
  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.