title: Sequential interaction of phenytoin and phenobarbital with fluorouracil.
abstract: OBJECTIVE
  We report a case of sequential interaction of phenytoin (PHT) and phenobarbital (PB) with fluorouracil (5-FU).
  
  
  METHODS
  A male patient aged 60 under treatment with PHT and PB in which serum concentrations of PHT (32.8 μg/ml) and PB (26.7 μg/ml) increased ~ 2-fold after the start of postoperative adjuvant therapy with calcium levofolinate (l-LV) and fluorouracil (5-FU). When the drug interactions of this case evaluated using the Drug Interaction Probability Scale, was assessed as "probable".
  
  
  CONCLUSIONS
  In this case, 5-FU increased PHT, which in turn may have increased the PB concentration, suggesting that when fluoropyrimidine antitumor agents are administered to patients receiving PHT in combination with other drugs, some measures should be taken in consideration of secondary effects of antitumor agents on other drugs that may possibly interact with PHT, including frequent monitoring of blood drug concentration.
authors.affiliation: Gamou Higashiohmi City Hospital, Higashiomi City, Japan.
authors.forename: Aiko
authors.initials: A
authors.lastname: Tsuda
authors.forename: Akiko
authors.initials: A
authors.lastname: Miki
authors.forename: Takeshi
authors.initials: T
authors.lastname: Togawa
authors.forename: Hiroki
authors.initials: H
authors.lastname: Satoh
authors.forename: Satoko
authors.initials: S
authors.lastname: Hori
authors.forename: Yasufumi
authors.initials: Y
authors.lastname: Sawada
mesh_terms: D004347:Drug Interactions; D005472:Fluorouracil / Q000494:pharmacology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010634:Phenobarbital / Q000009:adverse effects / Q000493:pharmacokinetics*; D010672:Phenytoin / Q000493:pharmacokinetics*
chemical_list: D010672:Phenytoin; D005472:Fluorouracil; D010634:Phenobarbital