title: Lansoprazole-tacrolimus interaction in Japanese transplant recipient with CYP2C19 polymorphism.
abstract: OBJECTIVE
  To report a patient with a high tacrolimus blood concentration after lansoprazole administration and assess the potential interaction between tacrolimus and lansoprazole.
  
  
  METHODS
  A 34-year-old Japanese man underwent a living-donor kidney transplantation having received tacrolimus, mycophenolate mofetil, and prednisolone for immunosuppression. Lansoprazole was administered from postoperative day 4 as prophylaxis of ulcers. The trough concentration of tacrolimus increased markedly after the introduction of lansoprazole, while results of liver function tests were within normal limits. Lansoprazole was stopped on day 15 and was replaced with famotidine on day 17. The trough concentration of tacrolimus returned to the therapeutic range after administration of lansoprazole ceased. Genetic analysis revealed a heterozygous mutation at exon 5 of the CYP2C19 gene (CYP2C19*1/*2) in this patient.
  
  
  CONCLUSIONS
  Lansoprazole is metabolized by 2 enzymes, CYP2C19 and CYP3A4. Since tacrolimus is also metabolized by CYP3A4, the blood concentration of tacrolimus in this patient who had a CYP2C19 gene mutation may have been elevated by decreased hepatic elimination of lansoprazole. An objective causality assessment revealed that this interaction was probable.
  
  
  CONCLUSIONS
  Trough concentrations of tacrolimus should be monitored closely for optimizing the dosage regimen in patients receiving concomitant lansoprazole.
authors.affiliation: Department of Pharmacy, Kyoto University Hospital, Faculty of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Kazushige
authors.initials: K
authors.lastname: Takahashi
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Motohashi
authors.forename: Atsushi
authors.initials: A
authors.lastname: Yonezawa
authors.forename: Masahiro
authors.initials: M
authors.lastname: Okuda
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Ito
authors.forename: Shingo
authors.initials: S
authors.lastname: Yamamoto
authors.forename: Osamu
authors.initials: O
authors.lastname: Ogawa
authors.forename: Ken-Ichi
authors.initials: K
authors.lastname: Inui
mesh_terms: D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D000328:Adult; D000897:Anti-Ulcer Agents / Q000378:metabolism / Q000494:pharmacology* / Q000627:therapeutic use; D001189:Aryl Hydrocarbon Hydroxylases / Q000235:genetics*; D065731:Cytochrome P-450 CYP2C19; D004357:Drug Synergism; D006801:Humans; D007166:Immunosuppressive Agents / Q000097:blood / Q000493:pharmacokinetics* / Q000627:therapeutic use; D016030:Kidney Transplantation; D064747:Lansoprazole; D008297:Male; D006899:Mixed Function Oxygenases / Q000235:genetics*; D009853:Omeprazole / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology* / Q000627:therapeutic use; D011110:Polymorphism, Genetic; D016559:Tacrolimus / Q000097:blood / Q000493:pharmacokinetics* / Q000627:therapeutic use
chemical_list: D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D000897:Anti-Ulcer Agents; D007166:Immunosuppressive Agents; D064747:Lansoprazole; D006899:Mixed Function Oxygenases; D001189:Aryl Hydrocarbon Hydroxylases; C045793:CYP2C19 protein, human; D065731:Cytochrome P-450 CYP2C19; D009853:Omeprazole; D016559:Tacrolimus