Methotrexate in TTT of rheumatoid arthritis

Methotrexate:• MOA: Is folic acid antagonist + cytotoxic +

immunosuppressant.• multiple IC enzymes → activation of ˉˉ ˉˉ

PMNLs, T-cells, and macrophages.• Is one of the first line drugs.• Used in >90% of RA cases.• One weekly.• Folic acid 5mg 24 hrs after methotrexate

dose to compensate for folic acid deficiency.

MOA of methotrexate (MTX):

S.E:1. Hepatotoxicity : common (monitor

LFTs),2. Myelosuppression (BMD),3. Teratogenicity.