Abstract
This study was designed to test the hypothesis that administration of clinical doses of cimetidine could affect the metabolic degradation of enflurane to inorganic fluoride via inhibition of the mixed function oxidase enzyme (MFOE) system. In Part I of the study 38 female patients undergoing gynaecologic surgery received, double blind, either cimetidine, 300 mg PO the night prior to surgery and 300 mg IV 30 minutes prior to anaesthesia induction or a placebo. In Part 2,24 patients received either cimetidine as in Part I, but with continued administration for 24 hours into the postoperative period, or a placebo. Anaesthesia in all cases was with enflurane in oxygen, via a closed circuit.
In both Parts 1 and 2 of the study there were no statistically significant differences between the two groups in serum fluoride levels at baseline, four hours or 24 hours postoperatively, or in the total urinary fluoride excretion during the first or second postoperative days. The authors speculate that this is due either to separate interactions of cimetidine and enflurane with the MFOE system or to the relatively low rate of enflurane meta-bolism.
Résumé
Cette étude a été congue afin de vérifier que I’hypothèse de L’administration de cimetidine à des doses cliniques peut affecter la dégradation métabolique de L’enflurane en fluorure inorganique par inhibition de la “mixed function oxidase enzyme system (MFOE).” Dans la première partie de L’étude 38 patients devant subir une chirugie gynécologique ont reçu à double insu soit de la cimétidine 300 mg PO la veille de la chirurgie et 300 mg IV 30 minutes avant l’induction de l’anesthésie, ou du placebo. Dans la deuxieme partie, 24 patients ont reçu soit de la cimetidine comme pour la premiere partie avec l’administration continue pour 24 heures dans la période post-opératoire, ou du placebo. Pour tous les cas l’anesthésie était accomplie avec de l’enflurane dans l’oxygène dans un circuit fermé.
Aucune différence statistiquement significative n’était observée entre les deux groupes dans les deux parties 1 et 2 quant au taux de fluore sérique lors du céntrôle, quatre heures et 24 heures post-opératoires ou dans le fluore total urinaire excrété le premier et le deuxième jour post-opératoire. Les outers supposent que ceci peut être du soit aux interactions séparées de la cimetidine et de l’enflurane sur le système MFOE ou au taux de métabolisme relativement bas de l’enflurane.
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Presented in part at the Annual Meeting of the American Society of Anesthesiologists, Atlanta, Georgia, 1983, and the Annual Meeting of the Canadian Anaesthetists’ Society, Toronto, Ontario, 1985.
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Yeager, M.P., Coombs, D.W., Dodge, C.P. et al. Effect of cimetidine on biotransformation of enflurane in man. Can Anaesth Soc J 33, 466–470 (1986). https://doi.org/10.1007/BF03010972
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DOI: https://doi.org/10.1007/BF03010972