title: Biodegradation of halothane, enflurane and methoxyflurane.
abstract: The biodegradation of halothane, enflurane and methoxyflurane was studied in 22 patients undergoing abdominal surgery, by measuring the uptake and elimination of each agent and the fluoride excretion in urine. Six control patients were anaesthetized with nitrous oxide in oxygen together with neuromuscular blocking drugs, five patients with nitrous oxide in oxygen and 0.93% halothane, five with nitrous oxide in oxygen and 1.30% enflurane, and six with nitrous oxide in oxygen and 0.31% methoxyflurane. The ratio of the fluoride excretion in urine to the total amount of fluoride contained in the amount of each anaesthetic agent absorbed during anaesthesia was estimated to be 17.7% for halothane, 2.3% for enflurane and 46.3% for methoxyflurane. The serum fluoride concentration increased to a maximum of 15.8 +/- 3.8 mumol litre-1 (mean +/- SD) at 6 h after anaesthesia with methoxyflurane, while it did not exceed 8 mumol litre-1 with the other anaesthetic agents.
mesh_terms: D000328:Adult; D000368:Aged; D000769:Anesthesia, Inhalation; D001711:Biotransformation; D004737:Enflurane / Q000378:metabolism*; D005260:Female; D005459:Fluorides / Q000378:metabolism; D006221:Halothane / Q000378:metabolism*; D006801:Humans; D008297:Male; D008733:Methoxyflurane / Q000378:metabolism*; D008738:Methyl Ethers / Q000378:metabolism*; D008875:Middle Aged; D013997:Time Factors
chemical_list: D008738:Methyl Ethers; D008733:Methoxyflurane; D004737:Enflurane; D005459:Fluorides; D006221:Halothane