Methotrexate, a medication originally developed for cancer treatment over 80 years ago, has been a cornerstone in managing psoriasis for approximately 60 years. Despite newer alternatives and potential side effects, methotrexate remains a significant option in treating psoriatic disease.
Mechanism of Action
Methotrexate operates by suppressing the immune system, which reduces inflammation and slows down the turnover of skin cells. The exact immune-modulating pathway targeted by methotrexate is still under investigation, with recent research pointing to its impact on the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway. This medication may also interfere with the folate pathway, leading prescribers to recommend folate supplements to mitigate side effects.
Treatment Considerations
Dr. Laura Coates, an associate professor at the University of Oxford specializing in psoriatic arthritis, emphasizes methotrexate’s enduring appeal due to its efficacy in both skin and joint symptoms and its cost-effectiveness. While newer therapies exist, methotrexate is often recommended when topical treatments prove insufficient, particularly for patients with joint involvement.
Dr. Astrid van Huizen of the Amsterdam University Medical Center underscores methotrexate’s established safety profile over eight decades of use compared to newer biologic agents, which have only been available for 24 years. The affordability of methotrexate further supports its role in widening access to treatment for psoriasis.
Administration and Dosage
Methotrexate is typically administered orally in pill form but is also available as an injection. Dosage varies depending on the severity of the condition, with oral doses ranging from 5 mg to 25 mg weekly. The medication is generally taken once a week, although splitting the dose can improve absorption and reduce side effects.
Potential Side Effects
While methotrexate is widely tolerated, common side effects include abdominal discomfort, bone marrow suppression, diarrhea, fever, and lowered infection resistance. Dr. Coates stresses the importance of open communication with healthcare providers to manage side effects effectively, potentially by adjusting folic acid intake or switching to injections.
Contraindications and Precautions
Certain individuals should avoid methotrexate, such as pregnant women or those planning pregnancy, individuals with significant liver disease, and heavy alcohol consumers. Regular blood tests are advised to monitor liver function, and patients are urged to inform their healthcare providers of any changes or concerns.
Drug Interactions
Methotrexate interacts with several medications, including NSAIDs, certain antibiotics, diuretics, and epilepsy medications. Patients should avoid live flu vaccines and proton pump inhibitors while taking methotrexate.
Long-Term Use
Patients may require patience as methotrexate typically takes months to demonstrate its full effectiveness. Treatment duration varies, with some individuals maintaining methotrexate use long-term and others discontinuing once symptoms are controlled.
Distinguishing Use in Cancer Treatment
In higher doses, methotrexate serves as a chemotherapy agent, targeting rapidly dividing cells in cancer. However, for autoimmune conditions like psoriasis, lower doses are used to suppress immune responses.
Conclusion
Methotrexate’s longstanding use in managing psoriasis underscores its significance, offering an affordable and effective treatment option. While caution is warranted due to potential side effects and drug interactions, methotrexate remains a vital therapeutic tool for patients with psoriatic disease, complementing the expanding array of available treatments. Effective communication with healthcare providers is essential to optimize treatment outcomes and ensure patient safety and well-being.
