[The use of methotrexate in cortico-resistant asthma].

: Methotrexate represents a new therapeutic modality in patients with corticoresistant asthma. Its mechanism of action is the competitive inhibition of the folate reducing enzyme, converting folic acid in tetrahydrofolate during the S phase of the cell cycle. It is 50% fixed to albumin and excreted by glomerular filtration and proximal tubule secretion.