Better efficacy of methotrexate given by intramuscular injection than orally in patients with rheumatoid arthritis

To compare the clinical efficacy of methotrexate and tolerance to the drug in patients with rheumatoid arthritis who were switched from intramuscular to oral administration because of a shortage of the intramuscular preparation.

143 patients were switched from intramuscular to oral methotrexate. Of these, 47 were switched back to the intramuscular form. A multiple choice questionnaire was sent by mail to evaluate clinical and biological criteria of efficacy and tolerance.

When methotrexate was first switched from intramuscular to oral administration, increased disease activity, exacerbation of morning pain and hand stiffness, duration of morning stiffness, increased joint pain, and increased joint swelling were observed. There was a greater frequency of gastrointestinal symptoms, but without a significant increase in liver abnormalities. When intramuscular methotrexate became available again, 47 of the 143 patients were switched back and were followed for at least three months. On average, disease manifestations were improved and side effects reduced by the switch.

Methotrexate given intramuscularly had improved clinical efficacy with fewer side effects than given orally. Intramuscular methotrexate administration should be considered when rheumatoid arthritis remains active in spite of high dose oral methotrexate.