Question: Why is it necessary to take folic acid with methotrexate?
Answer: Methotrexate (MTX) is a chemotherapy drug that prevents cell reproduction by interfering with folic acid activation. MTX is also used in the treatment of psoriatic arthritis and rheumatoid arthritis. Although very effective, its use potentially may produce serious side effects including nausea, mouth ulcers, blood problems, liver cirrhosis, and hair loss. Prolonged treatment with MTX may also lead to folic acid deficiency. To reduce the risk of these side effects, without fear of interfering with its efficacy, a maximum daily dose of 5mg of folic acid is recommended for those patients taking MTX on a regular weekly basis. (Answer provided by the late Dr. Raymond Federman, aka Dr. Bones, who passed away on September 2, 2003. The care of his patients even in retirement was always his joy.)