title: Acute neutropenia associated with initiation of febuxostat therapy for hyperuricaemia in patients with chronic kidney disease.
abstract: OBJECTIVE
  Febuxostat is a new non-purine selective inhibitor of xanthine oxidase for the treatment of hyperuricaemia in patients with gout. Febuxostat is recommended as the first-line pharmacologic urate-lowering therapy for gout in the American College of Rheumatology guidelines. Febuxostat has not been reported to cause severe complications, especially haematological abnormalities. Our objective is to report two cases of neutropenia associated with initiation of febuxostat therapy for hyperuricaemia in patients with chronic kidney disease (CKD).
  
  
  METHODS
  A 74-year-old woman with liver cirrhosis and CKD was treated with febuxostat for hyperuricaemia during hospitalization. Eleven days after febuxostat administration, she developed neutropenia. A 68-year-old man with type 2 diabetes mellitus on intermittent haemodialysis was treated with febuxostat for hyperuricaemia during hospitalization. Three days after febuxostat administration, he developed neutropenia. In the two cases, febuxostat treatment was discontinued and granulocyte colony-stimulating factor was administered, with concomitant recovery of the neutrophil count.
  
  
  CONCLUSIONS
  We believe this to be the first published case of neutropenia associated with initiation of febuxostat therapy for hyperuricaemia. According to the Naranjo probability scale, febuxostat was the probable cause of neutropenia. In view of the wide clinical usage of this drug, physicians and pharmacists should be alerted to this possible complication.
authors.affiliation: Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan. skobayashi@jikei.ac.jp
authors.forename: S
authors.initials: S
authors.lastname: Kobayashi
authors.forename: M
authors.initials: M
authors.lastname: Ogura
authors.forename: T
authors.initials: T
authors.lastname: Hosoya
mesh_terms: D000368:Aged; D000069465:Febuxostat; D005260:Female; D006074:Gout Suppressants / Q000009:adverse effects / Q000627:therapeutic use; D006801:Humans; D033461:Hyperuricemia / Q000188:drug therapy*; D008297:Male; D009503:Neutropenia / Q000139:chemically induced*; D051436:Renal Insufficiency, Chronic / Q000188:drug therapy*; D013844:Thiazoles / Q000009:adverse effects* / Q000627:therapeutic use*
chemical_list: D006074:Gout Suppressants; D013844:Thiazoles; D000069465:Febuxostat