O) is an inhalational anaesthetic
used in the 1960s and early 1970s, but withdrawn because of detrimental effects on the kidneys
. This was due to fluoride ions
being produced by its metabolism in the kidney. (This effect was considered to be dose-dependent, smaller doses for shorter periods being considered relatively safer).
Its minimum alveolar concentration (MAC) is 0.2, hence it is extremely potent. It has a high lipid solubility (oil:gas coefficient around 950) giving it a very slow onset/offset, this being undesirable for anesthetic purposes.
Even so, methoxyflurane is a powerful analgesic (pain-relieving) agent, at well below full anaesthetic doses. The vapour is sometimes said to have a pleasant, fruity aroma.
Methoxyflurane is used extensively in Australian ambulance services, and in St John Ambulance as an emergency analgesic.