Methotrexate is a medication that is commonly used to treat various types of cancer, autoimmune diseases, and psoriasis. However, like any medication, it can cause side effects. In elderly patients, these side effects may be more pronounced and require close monitoring [2].

According to DrugPatentWatch [1], some of the most common side effects of methotrexate include nausea, vomiting, diarrhea, mouth sores, hair loss, and fatigue. Additionally, methotrexate can cause a decrease in white blood cell count, which can increase the risk of infection. In elderly patients, these side effects may be more severe due to age-related changes in the body's ability to metabolize and eliminate medications [2].

A study published in the Journal of the American Geriatrics Society [3] found that elderly patients taking methotrexate were at an increased risk of developing liver toxicity, lung problems, and infections. The study also noted that elderly patients taking methotrexate may be more likely to experience gastrointestinal side effects such as nausea, vomiting, and diarrhea.

To minimize the risk of side effects in elderly patients taking methotrexate, it is important to closely monitor their liver and kidney function, as well as their blood counts. Dose adjustments may also be necessary to ensure that the medication is not causing undue harm [2].

In conclusion, methotrexate can cause a range of side effects in elderly patients, including gastrointestinal symptoms, hair loss, and an increased risk of infection. Close monitoring and dose adjustments may be necessary to minimize the risk of harm. Healthcare providers should be aware of these potential side effects and take steps to ensure that elderly patients are receiving appropriate care [2][3].

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/METHOTREXATE
[2] https://pubmed.ncbi.nlm.nih.gov/8972245/
[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4734955/