title: Severe pancytopenia associated with low-dose methotrexate therapy for rheumatoid arthritis.
abstract: OBJECTIVE
  To report the occurrence of severe pancytopenia associated with low-dose methotrexate (MTX) therapy for rheumatoid arthritis.
  
  
  METHODS
  Two patients developed severe pancytopenia after 10 days (cumulative dose 15 mg) and 23 months (cumulative dose 1030 mg), respectively, of low-dose MTX therapy for rheumatoid arthritis. Both patients had renal impairment. One died and the other recovered completely.
  
  
  CONCLUSIONS
  Pancytopenia is a rare adverse effect of low-dose oral MTX therapy. The exact mechanism for development of pancytopenia is unknown, although it is likely that several factors play a role. The most important risk factor for MTX toxicity is impaired renal function. This adverse effect may occur at any time during MTX therapy.
  
  
  CONCLUSIONS
  Severe pancytopenia associated with low-dose MTX therapy for rheumatoid arthritis is a potentially serious complication that may occur at any time during therapy. This adverse effect is more likely to occur in patients with renal impairment.
authors.affiliation: Internal Medicine Service, Infanta Cristina University Hospital, Héroes de Cascorro 9, 3o A, 06004 Badajoz, Spain.
authors.forename: J M
authors.initials: JM
authors.lastname: Calvo-Romero
mesh_terms: D000284:Administration, Oral; D000368:Aged; D018501:Antirheumatic Agents / Q000008:administration & dosage / Q000009:adverse effects*; D001172:Arthritis, Rheumatoid / Q000188:drug therapy*; D004305:Dose-Response Relationship, Drug; D017809:Fatal Outcome; D005260:Female; D006801:Humans; D008297:Male; D008727:Methotrexate / Q000008:administration & dosage / Q000009:adverse effects*; D010198:Pancytopenia / Q000139:chemically induced*
chemical_list: D018501:Antirheumatic Agents; D008727:Methotrexate