See the DrugPatentWatch profile for methotrexate

Methotrexate, a medication commonly used to treat various conditions such as rheumatoid arthritis, cancer, and psoriasis, can potentially interact with other medications, resulting in decreased effectiveness of the other drugs [2][3]. However, the specific interactions and mechanisms through which methotrexate may decrease the effectiveness of other medications are not explicitly outlined in the provided sources.

It is essential to consult a healthcare professional or pharmacist for detailed information on potential drug interactions when taking methotrexate or any other medication. They can provide guidance based on an individual's specific medical history and current medications [1][2][3].

Sources:

1. [DrugPatentWatch](https://www.drugpatentwatch.com/p/tradename/METHOTREXATE)
2. [NCBI - National Center for Biotechnology Information](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6360124/)
3. [Arthritis Foundation](https://www.arthritis.org/drug-guide/medication-topics/understanding-methotrexate)