Methotrexate toxicity

Methotrexate toxicity refers to the harmful side effects that can happen when the drug methotrexate causes damage to the body. Methotrexate is a medicine used to treat many conditions, including certain cancers (like leukemia and lymphoma), rheumatoid arthritis, psoriasis, and other autoimmune diseases. It works by blocking a key process that cells need to grow and divide. While this makes it useful for fighting cancer and calming overactive immune systems, it can also harm healthy cells — especially in the bone marrow, digestive tract, liver, kidneys, and lungs. Toxicity can happen at high doses (like those used in cancer treatment) or even at lower doses used for arthritis or skin conditions, especially if the drug builds up in the body over time. Risk is higher in people with kidney problems, low folate levels, or certain genetic variations that affect how their body processes the drug. Symptoms can range from mild nausea and mouth sores to serious problems like bone marrow failure, liver scarring, lung inflammation, and kidney damage. Treatment for methotrexate toxicity depends on how severe it is. Mild cases may just need the drug to be stopped or the dose reduced. Serious cases may require a rescue medicine called leucovorin (folinic acid), which helps protect healthy cells. Supportive care — such as fluids, blood transfusions, or treatment for infections — may also be needed. With prompt recognition and treatment, many people recover fully, but severe toxicity can be life-threatening.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

Bring these to your next appointment

• Q1.What signs of toxicity should I watch for at home, and when should I go to the emergency room?,How often do I need blood tests to monitor for side effects, and what are you checking for?,Should I take folic acid supplements, and if so, how much and when?,Are there any medications, supplements, or foods I should avoid while taking methotrexate?,Could my genetics affect how my body handles methotrexate, and should I be tested?,What happens to my underlying condition if methotrexate has to be stopped due to toxicity?,Is leucovorin or glucarpidase available at this hospital if I develop serious toxicity?

Common questions about Methotrexate toxicity