To develop clinical practice guidelines for the use of methotrexate in rheumatoid arthritis (RA), using the evidence-based approach and expert opinion.

A scientific committee used a Delphi procedure to select five questions, which formed the basis for developing recommendations. Evidence providing answers to the five questions was sought in the Cochrane databases, PubMed, and proceedings of meetings of the French Society for Rheumatology, European League Against Rheumatism, and American College of Rheumatology. Using this evidence, a group of rheumatologists developed and validated the recommendations. For each recommendation, the level of evidence and the extent of agreement among experts were specified.

The recommendations were as follows: 1: The starting dosage for methotrexate in patients with RA should not be less than 10 mg/week and should be determined based on disease severity and patient-related factors; 2: When a patient with RA shows an inadequate response to methotrexate, the dosage should be increased at intervals of 6 weeks, up to 20 mg/week, according to tolerance and patient-related factors; 3: When starting methotrexate treatment in a patient with RA, preference should be given to the oral route. A switch to the intramuscular or subcutaneous route should be considered in patients with poor compliance, inadequate effectiveness, or gastrointestinal side effects; 4: At present, there is no evidence indicating that a change in methotrexate dosage is in order when a TNF antagonist is given concomitantly; 5: The investigations that are mandatory before starting methotrexate therapy in a patient with RA consist of a full blood cell count, serum transaminase levels, serum creatinine with computation of creatinine clearance, and a chest radiograph. In addition, serological tests for the hepatitis viruses B and C and a serum albumin assay are recommended. In patients with a history of respiratory disease or current respiratory symptoms, lung function tests with determination of the diffusing capacity for carbon monoxide are recommended; 6: Investigations that are mandatory for monitoring methotrexate therapy in patients with RA consist of full blood cell counts and serum transaminase and creatinine assays. These tests should be obtained at least once a month for the first 3 months then every 4-12 weeks; 7: Folate supplementation can be given routinely to patients treated with methotrexate for RA. In practice, a minimal dosage of 5 mg of folic acid once a week, at a distance from the methotrexate dose, is appropriate; 8: In the event of respiratory symptoms possibly related to methotrexate toxicity, the drug must be stopped and symptom severity evaluated. Should evidence of serious disease be found, the patient should be admitted immediately or advice from a pulmonologist should be obtained immediately.

Recommendations about methotrexate therapy for RA were developed. These recommendations should help to improve practice uniformity and, ultimately, to improve the management of RA.