Which drug is the first-line disease-modifying antirheumatic drug for rheumatoid arthritis?

• A. Methotrexate
• B. Gold
• C. D-Penicillamine
• D. Cyclosporin A

Answer: (A)

The main idea is that methotrexate is the standard first-line disease-modifying antirheumatic drug for rheumatoid arthritis because it offers strong efficacy, a manageable safety profile at low weekly doses, and practical use in everyday practice. In RA, methotrexate acts anti-inflammatory through several mechanisms, including inhibition of enzymes in purine metabolism that leads to increased adenosine, a mediator with broad anti-inflammatory effects, and suppression of immune cell activity, which slows joint damage and progression over time. Clinically, it is given once weekly, in low to moderate doses, and can be taken orally or by subcutaneous injection. Folic acid is routinely added to reduce toxicity to the liver and bone marrow, and patients are monitored with regular blood counts and liver and kidney function tests because potential adverse effects include hepatotoxicity, cytopenias, mucositis, and, less commonly, interstitial lung disease. It is also teratogenic, so pregnancy must be avoided or planned carefully.

Historically used agents like gold salts or D-penicillamine have fallen out of favor due to limited efficacy and higher toxicity. Cyclosporin A is a powerful immunosuppressant but carries significant nephrotoxicity and other risks, and it is not considered a first-line DMARD for RA. For these reasons, methotrexate remains the best initial DMARD choice, providing the best balance of disease control, safety, and practicality for most patients.