Pneumocystis carinii pneumonia complicating low dose methotrexate treatment for rheumatoid arthritis

Thorax. 1991 Mar;46(3):205-7. doi: 10.1136/thx.46.3.205.


Low dose methotrexate has been used effectively for various rheumatic and non-rheumatic diseases. Three cases of Pneumocystis carinii pneumonia occurring during treatment of rheumatoid arthritis with low dose methotrexate are presented. Several mechanisms might contribute to impaired immunity and the rare development of opportunist lung infection with methotrexate. A high degree of suspicion may result in earlier diagnosis and treatment.

Publication types

  • Case Reports
  • Review

MeSH terms

  • Adolescent
  • Aged
  • Arthritis, Rheumatoid / complications
  • Arthritis, Rheumatoid / drug therapy*
  • Arthritis, Rheumatoid / immunology
  • Female
  • Humans
  • Methotrexate / administration & dosage
  • Methotrexate / therapeutic use*
  • Middle Aged
  • Opportunistic Infections / complications
  • Pneumonia, Pneumocystis / complications*


  • Methotrexate