Cimetidine and ranitidine do not affect enflurane metabolism in surgical patients.
Hepatic cytochrome-P-450-linked microsomal metabolism is inhibited by cimetidine, and to a lesser extent by ranitidine. Such an inhibition might protect against the metabolite-related toxicity of inhalation anesthetics. However, in comparison with the values measured in a control group, neither cimetidine (600 mg p.o. + 200 mg i.m.) nor ranitidine (150 mg p.o. + 50 mg i.m.), both administered 11-12 h before anesthesia, inhibited enflurane metabolism as assessed by the increase in plasma inorganic fluoride concentration and urinary fluoride excretion in 21 ASA I patients anesthetized with enflurane (end-tidal concentration 0.5 +/- 0.05% for 2-6 h). The inorganic fluoride concentration in the gastric juice remained low in all groups.
Oikkonen
M
M
Department of Anesthesia, Otolaryngological Hospital, Helsinki University Central Hospital, Finland.
Rosenberg
P H
PH
Saarnivaara
L
L
D000368:Aged; D002927:Cimetidine / Q000627:therapeutic use*; D002986:Clinical Trials as Topic; D004737:Enflurane / Q000009:adverse effects / Q000378:metabolism*; D005260:Female; D005459:Fluorides / Q000097:blood / Q000378:metabolism / Q000652:urine; D005750:Gastric Juice / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D011897:Random Allocation; D011899:Ranitidine / Q000627:therapeutic use*
D002927:Cimetidine; D011899:Ranitidine; D004737:Enflurane; D005459:Fluorides