What is the drug of choice for treating moderate to severe psoriasis?

• A. Topical corticosteroids
• B. Methotrexate
• C. Cyclosporine
• D. Phototherapy

Answer: (B)

The drug of choice for treating moderate to severe psoriasis is methotrexate. Methotrexate acts as a systemic immunosuppressant and is effective in reducing the rapid turnover of skin cells that characterizes psoriasis. It is especially beneficial for patients with more extensive disease or those who do not respond to topical treatments alone.

Methotrexate works by inhibiting dihydrofolate reductase, which disrupts DNA synthesis and cell proliferation. This action helps to reduce the inflammatory process in the skin and slows down the excessive growth of skin cells, leading to clearer skin and improved overall conditions for patients. Significant clinical improvements can often be seen within weeks of starting therapy.

While other treatments for psoriasis exist, such as topical corticosteroids and cyclosporine, methotrexate is generally preferred for moderate to severe cases due to its systemic effects and ability to address extensive lesions that topical agents may not sufficiently manage. Phototherapy is also an effective treatment option, but it may not be as convenient for patients who require systemic treatment or have a larger affected area. Therefore, for moderate to severe psoriasis specifically, methotrexate stands out as a first-line option.