Flucytosine conversion to fluorouracil in humans: does a correlation with gut flora status exist? A report of two cases using fluorine-19 magnetic resonance spectroscopy.
A relationship between the gut flora level, particularly gram-negative enterobacilli, and the in vivo flucytosine conversion to fluorouracil has been observed in humans from the fluorine-19 magnetic resonance spectroscopy analysis of urine from two patients treated with the flucytosine- (6 to 9 g/day) amphotericin B (1 mg/kg/day) combination. Indeed the percentage of fluorouracil metabolites was extremely low (less than 0.6% of total fluorinated compounds excreted) when the number of enterobacillary colonies was low (less than 10(3] and higher (3.5 to 8.8%) when enterobacillary colonies were under reconstitution or in the normal range (10(5) to 10(8]. The intestinal microflora assessment may therefore be of high interest to predict the risk of an additive flucytosine-induced myelotoxicity suspected to be due to fluorouracil during flucytosine chronic therapy.
Malet-Martino
M C
MC
IMRCP Laboratory, Université Paul Sabatier, Toulouse, France.
Martino
R
R
de Forni
M
M
Andremont
A
A
Hartmann
O
O
Armand
J P
JP
D000293:Adolescent; D000666:Amphotericin B / Q000627:therapeutic use; D004359:Drug Therapy, Combination; D004755:Enterobacteriaceae / Q000378:metabolism*; D005437:Flucytosine / Q000031:analogs & derivatives / Q000378:metabolism* / Q000627:therapeutic use / Q000652:urine; D005472:Fluorouracil / Q000378:metabolism* / Q000652:urine; D006090:Gram-Negative Bacteria / Q000378:metabolism; D006801:Humans; D007422:Intestines / Q000382:microbiology*; D009682:Magnetic Resonance Spectroscopy
D000666:Amphotericin B; D005437:Flucytosine; D005472:Fluorouracil