title: Leflunomide-induced pneumonitis in a patient with rheumatoid arthritis.
abstract: Leflunomide is a disease-modifying antirheumatic drug (DMARD) that has been available in Japan since August 2003. Leflunomide-induced interstitial pneumonitis has not been reported as an adverse effect in other countries. We report a suspected case of leflunomide-induced interstitial pneumonitis. A 77-year-old woman with rheumatoid arthritis and a history of methotrexate-induced pneumonitis developed sudden-onset dyspnea on exertion about 2 months after the administration of leflunomide. She maintained a high concentration of an active metabolite of leflunomide for more than 3 weeks after withdrawal of the drug. She did not respond to treatment and died. Leflunomide must be administered with caution to patients with a history of interstitial pneumonitis or drug-induced pneumonitis. If leflunomide-induced pneumonitis is suspected, the plasma concentration must be immediately checked, along with elimination and withdrawal of the medication.
authors.affiliation: Department of Respiratory Medicine, International Medical Center of Japan, Toyama, Tokyo.
authors.forename: Yu
authors.initials: Y
authors.lastname: Hirabayashi
authors.forename: Hisahiro
authors.initials: H
authors.lastname: Shimizu
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Kobayashi
authors.forename: Koichiro
authors.initials: K
authors.lastname: Kudo
mesh_terms: D000276:Adjuvants, Immunologic / Q000009:adverse effects*; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000188:drug therapy*; D005260:Female; D006801:Humans; D007555:Isoxazoles / Q000009:adverse effects* / Q000627:therapeutic use; D000077339:Leflunomide; D008168:Lung / Q000000981:diagnostic imaging / Q000473:pathology; D011014:Pneumonia / Q000139:chemically induced* / Q000000981:diagnostic imaging / Q000473:pathology; D011859:Radiography; D011877:Radionuclide Imaging
chemical_list: D000276:Adjuvants, Immunologic; D007555:Isoxazoles; D000077339:Leflunomide