[Dyspnea during administration of methotrexate: not anything to treat casually]

An important complication of methotrexate (MTX) treatment is illustrated by two case histories. Until recently pneumonitis was believed to be associated only with high dose MTX. Lately several cases of pneumonitis during treatment with low intermittent doses have been reported. The use of low dose intermittent MTX treatment in non-malignant diseases is growing fast and an increasing incidence of MTX pneumonitis is to be expected. Early recognition of the disorder may result in adequate treatment. The clinical picture varies from transient mild dyspnoea to progressive, sometimes fatal respiratory insufficiency. All 'new' pulmonary signs of patients treated with MTX should raise suspicion of MTX pneumonitis. Before treatment with MTX is instituted a chest radiograph should be made and pulmonary function testing should be performed. It is of great importance to inform patients carefully about the possibility of MTX pneumonitis and its symptoms. The prognosis of MTX pneumonitis is usually favourable.