Methotrexate, a medication commonly used to treat cancer and autoimmune diseases, can indeed interact with other drugs, potentially altering their efficacy [1].

Methotrexate is a potent inhibitor of dihydrofolate reductase, an enzyme involved in the metabolism of folic acid. This inhibition can affect the metabolism of other drugs, leading to altered efficacy or increased toxicity [1].

For instance, methotrexate can interact with non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen and naproxen. Concurrent use of these drugs can decrease the efficacy of methotrexate by competing for renal tubular secretion, leading to increased methotrexate levels and potential toxicity [1].

Additionally, methotrexate can interact with drugs that increase its elimination, such as probenecid, which is used to treat gout. Probenecid can decrease methotrexate levels, potentially reducing its efficacy [1].

Furthermore, methotrexate can interact with drugs that increase its toxicity, such as sulfasalazine, a medication used to treat inflammatory bowel disease and rheumatoid arthritis. Sulfasalazine can displace methotrexate from plasma proteins, increasing its free fraction and potential toxicity [1].

In conclusion, methotrexate can interact with other drugs, changing their efficacy. Therefore, it is crucial to inform healthcare providers about all medications being taken, including over-the-counter drugs and supplements, to prevent potential interactions [1].

Sources:
[1] DrugPatentWatch. "Methotrexate Drug Interactions." DrugPatentWatch.com. Accessed April 12, 2023. https://drugpatentwatch.com/drug/methotrexate/interactions.