Editor—Methoxyflurane, once a frequently used anaesthetic agent,1 is re-emerging as an inhalation analgesic. In modern practice, it is given in doses of up to 6 mL via a proprietary patient-controlled self-delivery device2 with an activated carbon filter designed to adsorb some methoxyflurane vapour from the patient’s exhaled breath.3
Methoxyflurane is an organic vapour, identified as causing local environmental contamination when administered in anaesthesia or analgesia, and can subsequently be detected on the breath and in the urine of occupationally exposed staff members.4
Methoxyflurane is eliminated directly by exhalation and in the urine, and is also metabolised to fluoride and other products.5 Fluoride is also eliminated renally, but can be bound to body tissue and bone…
*Excerpt online at https://bjanaesthesia.org/article/S0007-0912(20)30697-8/fulltext
2. Douglas Pharmaceuticals Ltd. Penthrox New Zealand data sheet. 2020. https://medsafe.govt.nz/profs/datasheet/p/penthroxinh.pdf. Date accessed: April 29, 2020. Google Scholar
3. Ruff R, Kerr S, Kerr D, Zalcberg D, Stevens J. 2018. Occupational exposure to methoxyflurane administered for procedural sedation: an observational study of 40 exposures. Br J Anaesth. 2018; 120:1435-1437.
4. Corbett TH, Ball GL. 1971. Chronic exposure to methoxyflurane: a possible occupational hazard to anesthesiologists. Anesthesiology. 1971; 34 : 532-537
5. Yoshimura N, Holaday DA, Fiserova-Bergerova V. Metabolism of methoxyflurane in man. Anesthesiology. 1976; 44 : 372-379