Methotrexate is prescribed either in pill form or in subcutaneous injections given every
week. The most common side effects of methotrexate are stomach upset, nausea and
fatigue. These side effects usually manifest themselves within 24 hours of taking
methotrexate and may last up to 24-48 hours. If these symptoms are present every day of
the week or occur far away from the time of methotrexate administration, it is unlikely that
methotrexate is the cause and you may be dealing with something else. If you are unsure,
we would suggest speaking with your pediatric rheumatology care team about your
concerns.