Iguratimod
1. Drug class
Conventional synthetic disease-modifying anti-rheumatic drug (csDMARD); NF-κB inhibitor.
2. Mechanism of action
It mainly inhibits the NF-κB pathway, reducing production of TNF-α, IL-6 and pro-inflammatory cytokines and mediators. It also directly suppresses B-Cell terminal differentiation and Immunoglobulin/ autoantibody production, thereby dampening the autoimmune response in rheumatoid arthritis.
3. Indications
- Rheumatoid arthritis (RA): approved and widely used in Japan and China, often in combination with methotrexate as a csDMARD.
- Used in India for RA as an add-on or alternative csDMARD, following local rheumatology practice patterns; formal national guideline positioning may vary.
4. Dosing
Starting dose: 25 mg once daily for 4 weeks to assess tolerability
Maintenance dose: 25 mg twice daily (total 50 mg/day) orally, with or after food to reduce GI upset.
As combination therapy: commonly used with methotrexate as per RA csDMARD protocols, with standard MTX dosing unchanged.
5. Dose adjustment
Hepatic impairment: Avoid in active liver disease or elevated transaminases; discontinuation if ALT/AST >2–3× ULN
Renal impairment: no specific adjustment usually required in mild to moderate impairment, but use cautiously and monitor, as detailed PK data are limited
Elderly: start at lower end of dosing range and titrate carefully due to higher risk of hepatic and hematologic adverse effects
6. Contraindications
- Known hypersensitivity to Iguratimod or any component of the formulation.
- Severe hepatic impairment or significant active liver disease (due to risk of hepatotoxicity).
- History of severe hematologic disorders such as aplastic anemia or significant bone marrow failure.
- Pregnancy and lactation are generally considered contraindications/strongly discouraged because of insufficient safety data and potential risk; use only if no alternatives and potential benefit justifies risk
7. Adverse effects
Common (usually dose-related and often reversible): diarrhea, nausea, vomiting, abdominal pain, decreased appetite, stomatitis, rash, itching, urticaria, photosensitivity, nasopharyngitis and upper respiratory symptoms.
Laboratory and serious adverse effects: Elevated ALT/AST; potential drug-induced liver injury, Bone marrow suppression (aplastic anemia/cytopenias), Severe hypersensitivity or anaphylaxis.
8. Special populations
Pregnancy and lactation
- Not recommended; insufficient human data, and immunomodulatory mechanism suggests potential risk to fetus or infant.
- Discontinue or avoid in women who are pregnant or planning pregnancy; use effective contraception while on therapy and for a period after discontinuation as per local label.
- Breastfeeding is generally discouraged during treatment.
