[Non-cancer uses of methotrexate]

Methotrexate, used for nearly 40 years as an antimetabolite for cancer therapy, also has indications in dermatology, rheumatology and pneumology. When given at low dosage, it has an antiinflammatory effect although the mechanism is not totally understood. Numerous therapeutic trials have been performed in chronic inflammatory diseases such as rheumatoid arthritis in the adult, juvenile polyarthritis and corticosteroid-dependent asthma. Methotrexate is effective in severe resistant forms of rheumatoid arthritis and is used either alone or in combination with other drugs as first intention therapy because of the good tolerance, patient compliance and ease of use. The beneficial effect in severe corticosteroid-dependent asthma remains to be demonstrated. It has also been used in severe forms of psoriasis and may be useful in other diseases with an autoimmune component. Other less common indications including Crohn's disease, ectopic pregnancy and pregnancy termination require confirmation. Tolerance and compliance are generally good, even for prolonged treatments and undesirable effects are almost always reversible at withdrawal.