Methotrexate is a commonly used drug for the treatment of various medical conditions, including cancer, autoimmune diseases, and ectopic pregnancy. The dosage of methotrexate depends on various factors, including age, weight, and medical condition.

According to the sources provided, there is limited information on dosage adjustments for methotrexate in older adults. However, it is essential to monitor older adults closely as they are more likely to experience adverse effects due to age-related changes in their body's metabolism and elimination of drugs [2].

The drug patent watch website provides information on the patent status of methotrexate and its various formulations but does not offer any information on dosage adjustments for older adults [1].

The UpToDate article on the therapeutic use and toxicity of high-dose methotrexate discusses the use of high-dose methotrexate in cancer treatment and provides guidelines for monitoring and adjusting the dosage based on renal function, serum methotrexate levels, and other factors. However, this article does not provide specific information on dosage adjustments for older adults [2].

A study published in the National Library of Medicine suggests that older adults may require a lower dose of methotrexate due to age-related changes in their body's metabolism and elimination of drugs. The study recommends close monitoring of older adults for adverse effects and individualizing the dosage based on their medical condition and other factors [3].

In conclusion, while there is limited information on dosage adjustments for methotrexate in older adults, it is essential to monitor them closely and individualize the dosage based on their medical condition and other factors. It is recommended to consult with a healthcare provider before making any changes to the dosage of methotrexate [2][3].

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/METHOTREXATE
[2] https://www.uptodate.com/contents/therapeutic-use-and-toxicity-of-high-dose-methotrexate
[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2718993/