Treatment for polyarticular subgroup of Juvenile Idiopathic Arthritis
Patients with low disease activity at diagnosis are treated with NSAIDs and intraarticular steroids. Patients with moderate to high disease activity at diagnosis are often started on a disease-modifying antirheumatic drug (DMARD), typically methotrexate. Biologics (often TNFα inhibitors) are typically added for refractory disease but may also be considered as initial therapy in patients with high disease activity or poor prognostic features such as erosive changes. TNFα inhibitors can be used as monotherapy or in combination with methotrexate.
- • Methotrexate: Start at 10–15 mg/m 2 per week. Can be given orally or subcutaneously (SQ). Usual SQ maximum dose is 25 mg/week. SQ formulation allows greater absorption. Children require and tolerate higher doses than adults owing to differences in metabolism.
- • Sulfasalazine: 30–50 mg/kg per day (max 2000 mg/day) orally, divided twice daily.
- • Leflunomide: <20 kg (10 mg every other day, orally), 20–40 kg (10 mg daily, orally); >40 kg (20 mg daily, orally).
- • Etanercept: 0.8 mg/kg per week SQ weekly (max 50 mg weekly).
- • Adalimumab: 10kg to <15kg (10mg SQ every 2 weeks); 15mg to <30kg (20 mg SQ every 2 weeks); >30 kg (40 mg SQ every 2 weeks).
- • Infliximab: 5 mg/kg intravenously (IV) at 0, 2, 6 weeks and then every 4–8 weeks.
- • Tocilizumab: IV:<30 kg (10 mg/kg IV every 4 weeks); >30 kg (8 mg/kg IV every 4 weeks).
- • SQ injection: <30kg (162mg SQ every 3 weeks); >30kg (162mg SQ every 2 weeks)
- • Abatacept: (≥6 years): IV: 10 mg/kg (max 1000 mg) IV at 0, 2, 6 weeks, then every 4 weeks. SQ injection: 10–25 kg (50 mg SQ once weekly); 25–50 kg (87.5 mg SQ once weekly); >50 kg (125 mg SQ once weekly) SQ injection: <30kg (162mg SQ every 3 weeks); >30kg (162mg SQ every 2 weeks).
- • Rituximab: 750 mg/m 2 (max 1000 mg) IV at 0 and 2 weeks. Used in refractory RF+ polyarticular disease.