Methotrexate is a medication used to treat a variety of conditions, including cancer, autoimmune diseases, and ectopic pregnancy. While it is generally considered safe and effective, there may be age-related side effects to consider.

According to Drug Patent Watch [1], the prescribing information for methotrexate warns that the medication should be used with caution in elderly patients due to their increased risk of toxicity. The drug can affect the liver, kidneys, and bone marrow, which can be especially problematic in older adults who may already have compromised organ function. However, the prescribing information does not specify a particular age at which caution should be exercised.

A study published in the journal Clinical Pharmacokinetics [2] found that age can affect the way methotrexate is metabolized in the body. Specifically, the study found that older adults had lower clearance rates of the drug, meaning it stayed in their system longer than in younger patients. This could potentially increase the risk of side effects.

A review of methotrexate use in rheumatoid arthritis, published in the National Library of Medicine [3], notes that while the drug is generally well-tolerated, it can cause side effects such as nausea, fatigue, and hair loss. The review does not specifically address age-related side effects.

Overall, while methotrexate is considered safe and effective for a variety of conditions, caution should be exercised in elderly patients due to their increased risk of toxicity. Patients of all ages should be monitored for potential side effects, and any concerns should be discussed with a healthcare provider.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/METHOTREXATE
[2] https://pubmed.ncbi.nlm.nih.gov/8972245/
[3] https://www.ncbi.nlm.nih.gov/books/NBK556114/