Methotrexate is a medication that is used to treat a variety of conditions, including cancer and autoimmune diseases. However, it can also cause toxicity, which can be particularly concerning in older patients.

According to Drug Patent Watch [1], Methotrexate is a widely used medication that has been on the market for many years. It is used to treat a variety of conditions, including cancer, rheumatoid arthritis, and psoriasis. However, the website does not provide any information about the incidence of toxicity in older patients.

A study published in the journal Clinical Pharmacokinetics [2] notes that methotrexate toxicity is a concern in patients of all ages, but that it may be more common in older patients. The study suggests that older patients may be more susceptible to toxicity due to age-related changes in the way the body processes the medication. The study recommends that older patients be closely monitored for signs of toxicity.

According to UpToDate [3], methotrexate toxicity can cause a variety of symptoms, including nausea, vomiting, diarrhea, mouth sores, and skin rash. In severe cases, it can cause liver damage, kidney damage, and bone marrow suppression. The website notes that older patients may be more susceptible to toxicity due to age-related changes in the way the body processes the medication. The website recommends that older patients be closely monitored for signs of toxicity and that their dosage be adjusted as needed.

In conclusion, while there is no definitive answer as to whether methotrexate toxicity is common in older patients, the available evidence suggests that it may be more common in this population. Older patients may be more susceptible to toxicity due to age-related changes in the way the body processes the medication. As such, it is important for older patients who are taking methotrexate to be closely monitored for signs of toxicity and to have their dosage adjusted as needed.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/METHOTREXATE
[2] https://pubmed.ncbi.nlm.nih.gov/8972245/
[3] https://www.uptodate.com/contents/therapeutic-use-and-toxicity-of-high-dose-methotrexate