Iguratimod is a novel, orally administered small-molecule disease-modifying anti-rheumatic drug (DMARD) used primarily for the treatment of rheumatoid arthritis (RA). It is a synthetic compound with a unique dual mechanism of action, inhibiting both the production of inflammatory cytokines (like IL-6, IL-8, TNF-α) and immunoglobulin production by B cells. It is indicated for patients with active RA who have had an inadequate response to conventional DMARDs like methotrexate.
Adult: 25 mg orally twice daily (total 50 mg/day). After achieving adequate response, some guidelines suggest maintenance with 25 mg once daily, but the standard is twice daily. Must be taken on an empty stomach.
Note: Swallow the tablet whole with a glass of water. Take on an empty stomach, at least 1 hour before or 2 hours after a meal. Do not crush or chew. Dosing should be consistent, at approximately the same time(s) each day.
Iguratimod exerts its anti-inflammatory and immunomodulatory effects through a dual mechanism: 1) Inhibition of pro-inflammatory cytokine production (notably IL-6, IL-8, TNF-α, and MMPs) from synovial fibroblasts and macrophages via suppression of nuclear factor-kappa B (NF-κB) activation. 2) Inhibition of immunoglobulin (IgG, IgM) production by activated B-lymphocytes, potentially by suppressing the activity of transcription factors like NF-AT.
Pregnancy: CONTRANDICATED. Category X (US FDA). Animal studies have shown teratogenicity and embryolethality. Women of childbearing potential must use effective contraception during and for at least 6 months after treatment. Discontinue immediately if pregnancy occurs.
Driving: Generally safe. However, patients should be cautioned as dizziness or headache may occur, which could impair ability.
| Methotrexate | Increased risk of hepatotoxicity and bone marrow suppression. Monitor LFTs and CBC closely. | Major |
| Other Hepatotoxic Drugs (e.g., Paracetamol high dose, Azathioprine, Leflunomide) | Additive risk of liver damage. Requires enhanced monitoring. | Major |
| CYP2C19 Inhibitors (e.g., Omeprazole, Fluconazole, Fluvoxamine) | May increase iguratimod plasma concentration, increasing toxicity risk. | Moderate |
| CYP2C19 Inducers (e.g., Rifampicin, Carbamazepine) | May decrease iguratimod plasma concentration, reducing efficacy. | Moderate |
| Warfarin | Potential for increased INR and bleeding risk due to protein binding displacement and possible effects on coagulation. Monitor INR frequently. | Major |
| Live Vaccines (e.g., MMR, Varicella, Yellow Fever) | Increased risk of vaccine-induced infection. Avoid vaccination during therapy. | Major |