• Methoxyflurane is a ‘new-to-Canada’, (May 2018, Health Canada approval) self-administered, inhalational analgesic that may contribute to quicker access to pain control for patients, support for brief painful procedures, and during patient transports in the out-of-hospital setting.
• The handheld delivery system may permit less staff time and monitoring.
• Further experience in the Canadian prehospital and in-hospital environments is required to determine if and where methoxyflurane may best fit in our practices. In 2018-2019, BC Emergency Health Services is trialing methoxyflurane at select ambulance stations in British Columbia. Therefore, BC Emergency physicians will receive patients who have been inhaling this medication.
• A cost-analysis that compares personnel, ancillary equipment and medication between available modalities would be of value.

• No longer used as a general anesthetic due to acute kidney failure with prolonged use.

Indication:

Moderate to severe pain associated with trauma in conscious adults or for performing brief interventional medical procedures.

Contraindications:

Dosage: Initial dose: 3 mL, may repeat another 3 mL after 20 minutes if needed; maximum dose: 6 mL/day.

• Do not use on consecutive days if two doses were given (6 ml) on day 1, which wouldn’t be our common approach.
• Consecutive days at 3 mL would be fine (example, supporting daily burn dressing change up to 5 days; then we hit the 15 ml weekly max).
• Use lowest effective dosage to provide analgesia.
• A treatment course should be limited to a total dose of 15 mL/week (no more than 6 mL/48 hours).
• Treatment courses should not be repeated at an interval of less than 3 months.

Route of Administration:  Self-administration as needed under direct supervision.

Onset: Rapid (<5 minutes; 6-8 breaths).

Duration of action: 25 to 30 minutes (continuous inhalation) or ~60 minutes (intermittent inhalation).

Distribution: Highly lipophilic.

Metabolism: Hepatic.

Elimination: Urine (~60%, as metabolites); respiratory (~40%, unaltered or as carbon dioxide).

Side Effects:

• Major: Dizziness, headache.
• Minor: Drowsiness, nausea, euphoria, anxiety, flushed skin, blood pressure changes, cough, dry mouth.

Dependent upon the patient’s clinical presentation.

1. Blair, H. A., & Frampton, J. E. (2016). Methoxyflurane: a review in trauma pain. Clinical drug investigation, 36(12), 1067-1073.

   
   

2. Coffey, F., Dissmann, P., Mirza, K., & Lomax, M. (2016). Methoxyflurane analgesia in adult patients in the emergency department: a subgroup analysis of a randomized, double-blind, placebo-controlled study (STOP!). Advances in therapy, 33(11), 2012-2031.

   
   

3. Jephcott, C., Grummet, J., Nguyen, N., & Spruyt, O. (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.

   
   

4. Methoxyflurane. Lexi-Drugs. Lexicomp. Wolters Kluwer Health, Inc. Riverwoods, IL. Available at: www.online.lexi.com. Accessed March 19, 2019.

   
   

5. Porter, K. M., Siddiqui, M. K., 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.