Methotrexate is a medication used to treat various types of cancer and autoimmune diseases such as rheumatoid arthritis. The dosage of methotrexate recommended for elderly patients depends on several factors, including the patient's age, weight, and medical history.

According to the drug patent watch [1], the recommended dosage of methotrexate varies depending on the condition being treated. For rheumatoid arthritis, the initial dose is usually 7.5 mg once a week, which can be increased to 20-25 mg per week over time. For cancer treatment, the dosage is much higher, typically ranging from 30-500 mg per week, depending on the type and stage of cancer.

A study published in the British Medical Journal [2] found that methotrexate can be safely used in elderly patients with rheumatoid arthritis, but caution should be exercised when prescribing higher doses. The study recommended starting with a low dose and gradually increasing it as tolerated.

Another study published in the Journal of Rheumatology [3] found that elderly patients with rheumatoid arthritis who were treated with methotrexate had a lower risk of developing cardiovascular disease than those who were not treated with methotrexate. The study did not provide specific dosage recommendations for elderly patients.

In conclusion, the recommended dosage of methotrexate for elderly patients depends on the condition being treated, and caution should be exercised when prescribing higher doses. It is recommended to start with a low dose and gradually increase it as tolerated. It is important to consult with a healthcare provider to determine the appropriate dosage for each individual patient based on their medical history and other factors.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/METHOTREXATE
[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1741826/
[3] https://pubmed.ncbi.nlm.nih.gov/8972245/