methoxyflurane at a glance
Medicine class
Volatile inhaled analgesic; it is not an opioid.
Licensed use
Emergency relief of moderate to severe trauma-related pain in conscious patients aged 6 years and older.
Administration
The patient breathes the vapour through a handheld inhaler under trained supervision.
After use
Do not drive or operate machinery while dizzy, drowsy or sleepy.
What is methoxyflurane used for?
Uses include:
Licensed: emergency relief of moderate to severe trauma-related pain in conscious patients aged 6 years and older.
Off-licence: some NHS services use methoxyflurane as a pain-control option during colonoscopy.
How does methoxyflurane work?
Methoxyflurane is a fluorinated volatile agent that produces pain relief at low inhaled concentrations without being used to induce general anaesthesia. Its precise analgesic mechanism has not been fully established.
How to take methoxyflurane
A trained healthcare professional prepares the inhaler and explains its use. The patient breathes in and out through the mouthpiece, beginning gently, and adjusts inhalation according to pain relief while remaining supervised.
Keep the wrist loop in place.
Exhale back through the inhaler so the activated-carbon chamber captures exhaled vapour.
Follow the supervising professional’s instructions and stop if excessive drowsiness, breathing difficulty, or other concerning symptoms occur.
methoxyflurane side effects
Common or expected effects
- Dizziness
- Headache or sleepiness
- Altered taste or a euphoric mood
- Cough or nausea
- Fatigue or feeling drunk
Get urgent medical advice
- Slow or difficult breathing, low oxygen levels, or marked loss of consciousness
- A severe allergic reaction
- Liver injury, which may cause jaundice, dark urine, or persistent nausea
- Kidney injury, which may cause a marked change in urination or swelling
methoxyflurane in pregnancy
Pregnancy data are limited. Particular care is advised during pregnancy, especially in the first trimester, and the clinician should assess whether another pain-relief option is more appropriate.
methoxyflurane while breastfeeding
It is not known whether methoxyflurane passes into human milk. A clinician should assess its use cautiously during breastfeeding and discuss suitable alternatives where appropriate.
methoxyflurane interactions
Tell the supervising clinician about all medicines, recreational drugs, and alcohol because clinically important additive or metabolic interactions can occur.
Isoniazid, rifampicin, carbamazepine, phenobarbital, efavirenz or nevirapine
These enzyme-inducing medicines may increase methoxyflurane metabolism and its potential toxicity, so concomitant use should be avoided.
Opioids, sedatives, sleeping medicines, general anaesthetics, muscle relaxants or sedating antihistamines
Combined use can increase drowsiness and respiratory or central nervous system depression, requiring close observation.
Alcohol
Alcohol can add to sedation and may increase methoxyflurane metabolism and potential toxicity.
Common questions about methoxyflurane
Answers are fully visible for fast scanning and source review.
Is methoxyflurane an opioid?
No. It is a volatile inhaled analgesic related to fluorinated anaesthetic agents, used at analgesic rather than anaesthetic concentrations.
Does methoxyflurane put you to sleep?
It is intended to reduce pain while the patient remains conscious, although dizziness and drowsiness can occur. It must not be used as a general anaesthetic.
Who can use methoxyflurane?
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.