DOC in rheumatoid arthritis is –
**Core Concept**
Rheumatoid arthritis (RA) is a chronic autoimmune disorder characterized by inflammation and joint damage. The disease-modifying antirheumatic drugs (DMARDs) are a class of medications used as the first-line treatment for RA.
**Why the Correct Answer is Right**
The disease-modifying antirheumatic drug (DMARD) of choice (DOC) in rheumatoid arthritis is methotrexate. Methotrexate works by inhibiting the enzyme dihydrofolate reductase (DHFR), which is essential for DNA synthesis and cell division. This results in the reduction of inflammation and slowing of disease progression. Methotrexate also has immunosuppressive properties, which help in reducing the production of inflammatory cytokines.
**Why Each Wrong Option is Incorrect**
**Option A:** Sulfasalazine is another DMARD used in the treatment of RA, but it is not the DOC. Sulfasalazine has anti-inflammatory properties and is often used in combination with methotrexate.
**Option B:** Hydroxychloroquine is a DMARD used in the treatment of RA, but it is not the DOC. Hydroxychloroquine has anti-inflammatory and immunomodulatory effects, but it is often used in combination with other DMARDs.
**Option C:** Leflunomide is a DMARD used in the treatment of RA, but it is not the DOC. Leflunomide works by inhibiting the enzyme dihydroorotate dehydrogenase, which is involved in pyrimidine synthesis.
**Clinical Pearl / High-Yield Fact**
Methotrexate is the most commonly used DMARD in RA due to its efficacy and safety profile. However, it requires regular monitoring of liver function tests and complete blood counts.
**Correct Answer: A. Methotrexate**