Isoniazid-induced enflurane defluorination in humans.
Serum inorganic fluoride (F-) levels were measured in 20 surgical patients treated with 300 mg isoniazid per day for periods of up to one year, prior to anesthesia with enflurane. Thirty-six control patients anesthetized with enflurane, but taking no drugs, also were studied. Regression lines for peak serum fluoride were plotted against enflurane exposure in MAC-hours. Nine isoniazid-treated patients had fluoride levels significantly (P less than 0.001) higher (y = 22.2x + 12.0) than either the 11 other isoniazid-treated patients (y = 5.0x + 8.2) or the 36 control patients (y = 5.4x + 6.3). Peak serum fluoride values in three patients exceeded 100 microM but in no patient did values exceed 10 microM by 48 h after anesthesia. It was concluded that isoniazid treatment resulted in enzyme induction in the nine patients with high peak fluoride levels. This pattern, i.e., induction occurring in approximately one-half the patients, probably is related to the genetically determined bimodal distribution of rapid and slow acetylation of isoniazid.
D004347:Drug Interactions; D004737:Enflurane / Q000378:metabolism*; D004790:Enzyme Induction / Q000187:drug effects; D005260:Female; D005459:Fluorides / Q000097:blood / Q000378:metabolism; D006801:Humans; D007538:Isoniazid / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D010641:Phenotype
D004737:Enflurane; D005459:Fluorides; D007538:Isoniazid