A 58-year-old woman with a 10-year history of rheumatoid arthritis presents with progressive joint destruction, morning stiffness lasting 2 hours, and elevated inflammatory markers (ESR 68 mm/h, CRP 12 mg/dL). She has not received any disease-modifying antirheumatic drug (DMARD) therapy. What is the drug of choice for initial disease-modifying therapy?

Question

Accepted Answer

D. Methotrexate. ## Rheumatoid Arthritis: First-Line DMARD Therapy

### Pathophysiology of RA
Rheumatoid arthritis is a chronic, systemic autoimmune disease characterized by:
- Th1/Th17-mediated synovial inflammation
- TNF-α and IL-6 overproduction by activated macrophages and fibroblasts
- Immune complex deposition and complement activation
- Progressive cartilage and bone destruction if untreated

### First-Line DMARD: Methotrexate

**Key Point:** Methotrexate is the gold standard first-line DMARD for rheumatoid arthritis. It is the anchor drug in combination therapy and is used in nearly all RA treatment regimens.

**High-Yield:** Methotrexate mechanism in RA:
- Inhibits dihydrofolate reductase → ↓ purine and pyrimidine synthesis
- Reduces T-cell and B-cell proliferation
- Decreases TNF-α, IL-6, and IL-8 production (anti-inflammatory effect)
- Onset of action: 6–12 weeks
- Peak effect: 3–6 months

### Dosing & Administration
- **Starting dose:** 7.5–10 mg/week (oral or subcutaneous)
- **Titration:** Increase by 2.5–5 mg/week every 4–8 weeks to target 15–25 mg/week
- **Folic acid supplementation:** 1 mg daily (or 5 mg on non-methotrexate days) to reduce toxicity

### Efficacy & Outcomes
- **ACR20 response:** ~50% at 12 weeks
- **Remission/low disease activity:** Achievable in 40–50% when combined with biologics
- **Joint damage prevention:** Methotrexate monotherapy slows radiological progression; combination therapy with biologics achieves remission in many patients

### Monitoring Requirements
- **Baseline:** CBC, LFTs, renal function, hepatitis B/C serology, TB screening
- **During therapy:** CBC and LFTs every 8–12 weeks
- **Toxicity:** Hepatotoxicity (rare with modern dosing), myelosuppression, mucositis, teratogenicity (absolute contraindication in pregnancy)

### First-Line DMARD Comparison

| Agent | Onset | Efficacy | Toxicity | Role |
|-------|-------|----------|----------|------|
| **Methotrexate** | 6–12 weeks | High | Moderate (hepatotoxicity, myelosuppression) | **Anchor drug, first-line** |
| Sulfasalazine | 8–12 weeks | Moderate | GI upset, rash, hepatotoxicity | Alternative monotherapy; part of triple therapy |
| Hydroxychloroquine | 8–12 weeks | Low–moderate | Well-tolerated; retinopathy (rare) | Mild RA; adjunct therapy |
| Leflunomide | 4–8 weeks | High | Hepatotoxicity, teratogenicity | Alternative if methotrexate intolerant |

**Clinical Pearl:** Biologic DMARDs (TNF-α inhibitors, IL-6 inhibitors, JAK inhibitors) are NOT first-line monotherapy. They are added to methotrexate in patients with inadequate response or used in combination regimens for rapid remission induction.

### Why Methotrexate is First-Line
1. **Proven efficacy:** Decades of clinical data; slows radiological progression
2. **Cost-effectiveness:** Inexpensive compared to biologics
3. **Anchor drug:** Used in combination with all other DMARDs and biologics
4. **Tolerability:** Manageable toxicity profile with appropriate monitoring
5. **Guideline consensus:** ACR, EULAR, and Indian Rheumatology Association recommend methotrexate as first-line

**Warning:** Corticosteroids (prednisolone) are NOT disease-modifying agents. They provide symptomatic relief but do NOT prevent joint destruction. They should be used as adjunctive therapy only, at the lowest effective dose, while waiting for DMARD onset.

### Treatment Algorithm

```mermaid
flowchart TD
  A[Confirmed RA diagnosis]:::outcome --> B[Start Methotrexate]:::action
  B --> C{Response at 12 weeks?}:::decision
  C -->|Adequate response| D[Continue MTX monotherapy]:::action
  C -->|Inadequate response| E[Add biologic DMARD]:::action
  E --> F[TNF-α inhibitor + MTX]:::action
  F --> G{Remission/LDA?}:::decision
  G -->|Yes| H[Maintain combination therapy]:::action
  G -->|No| I[Switch biologic or add second agent]:::action
```

Answer

A. Prednisolone

Answer

B. Infliximab

Answer

C. Sulfasalazine

Explanation

Rheumatoid Arthritis: First-Line DMARD Therapy

Pathophysiology of RA

First-Line DMARD: Methotrexate

Dosing & Administration

Efficacy & Outcomes

Monitoring Requirements

First-Line DMARD Comparison

Why Methotrexate is First-Line

Treatment Algorithm

Practice similar questions

Join our NEET PG community

Agent	Onset	Efficacy	Toxicity	Role
Methotrexate	6–12 weeks	High	Moderate (hepatotoxicity, myelosuppression)	Anchor drug, first-line
Sulfasalazine	8–12 weeks	Moderate	GI upset, rash, hepatotoxicity	Alternative monotherapy; part of triple therapy
Hydroxychloroquine	8–12 weeks	Low–moderate	Well-tolerated; retinopathy (rare)	Mild RA; adjunct therapy
Leflunomide	4–8 weeks	High	Hepatotoxicity, teratogenicity	Alternative if methotrexate intolerant