the analgesic effect of opioids is due to their
Opioid Opioids are substances that act on opioid receptors to produce morphine-like effects.[2] Medically they are primarily used for pain relief, including anesthesia.[3] Other medical uses include suppression of diarrhea, treating opioid use disorder, reversing opioid overdose, suppressing cough, and suppressing opioid induced constipation.[3] Extremely potent opioids such as carfentanil are only approved for veterinary use.[4] Opioids are also frequently used non-medically for their euphoric effects or to prevent withdrawal.[5]
Methoxyflurane Methoxyflurane has been extensively used since the 1970s in Australia as an emergency analgesic for short-term use, mostly by the Australian and New Zealand Defence Forces,[3] and the Australian ambulance services.[4][5][6] The drug is currently only available from one manufacturer (Medical Developments International, Melbourne, Victoria, Australia). It is self-administered to children and adults using the Penthrox inhaler, a hand-held inhaler device, known as "the green whistle".[3][4][7][8] A non-opioid alternative to morphine, it is also easier to use than nitrous oxide.[9] As of 2010, methoxyflurane was listed under the Pharmaceutical Benefits Scheme for the initial management of pain due to acute trauma, as well as for brief painful procedures such as changing of wound dressings or for patient transport.[9] A portable, disposable, single-use inhaler device (the Penthrox inhaler), along with a single 3 milliliter brown glass vial of methoxyflurane is provided in doctor's kits that allows conscious hemodynamically stable patients (including children over the age of 5 years) to self-administer the drug, under supervision.[9]