Methoxyflurane is a halogenated ether anaesthetic. It is highly lipid soluble, allowing for slow induction and emergence.
Uses within SJA
Within SJA it is used as a patient-administered, emergency analgesic.
To reduce environmental exposure, it must be used with accompanying charcoal filter and the vehicle extractor fan.
When administered via inhalation, analgesia commences within 6-8 breathes.
Methoxyflurane is rapidly absorbed through the respiratory system.
It is distributed into fatty tissue where it may be stored for several days.
50 -70% of methoxyflurane is metabolised by the liver to fluride and oxalic acid.
Methoxyflurane metabolites are excreted in urine and some of the unmetabolised drug exhaled during respiration.
Rapid onset of analgesia
Minimal effect on GCS
Easily administered by the patient
Methoxyflurane has relatively mild haemodynamic effects.
May cause respiratory depression and moderate hypotension when used in larger doses.
Nausea has been identified in 4.8% of patients, somewhat lower than other analgesics.
Nephrotoxicity was first identified during the 1960’s when used as an anaesthetic. Its use as an anaesthetic was abandoned in the mid-1970’s. For this reason, it is not recommended for use in patients with renal compromise.
Duration of Action
It provides effective analgesia for 20-30 minutes with continuous use.
Other Drug Interactions
Interactions with other medications are unlikely when used in sub-anaesthetic doses for short periods.
When used in anaesthetic doses, concurrent use with tetracyclines can potentiate nephron / hepatic toxicity.
Did You Know?
Methoxyflurane was first isolated by William T. Miller in the 1940’s. His work on Fluorine was instrumental in separating Uranium isotopes during the Manhattan Project.
Default Author St John WA
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