Methotrexate sodium (Rheumatrex®; Trexall®; Amethopterin; MTX) is in a class of medications called antimetabolites. Available by prescription, methotrexate is FDA approved to treat severe psoriasis that cannot be controlled by other treatments. It is taken by mouth in tablet form.

If you have been prescribed methotrexate for psoriasis, it is essential that you follow your doctor’s instructions exactly. Methotrexate treats psoriasis by slowing the growth of skin cells to stop scales from forming, because it works by decreases immune system activity. Methotrexate may cause side effects including dizziness; drowsiness; headache; swollen; tender gums; decreased appetite; reddened eyes; and hair loss. If you experience any of these side effects for a prolonged period of time, tell your doctor.

Serious side effects associated with methotrexate include blurred vision or sudden loss of vision; seizures; confusion; weakness or difficulty moving one or both sides of the body; and loss of consciousness. If you experience any of these symptoms call your doctor immediately.

Methotrexate is FDA pregnancy category X which means it can cause birth defects in an unborn baby. Do not use methotrexate to treat psoriasis if you are pregnant. Tell your doctor right away if you become pregnant during treatment.