Methotrexate
MTX is a folic acid antagonist. DNA synthesis is inhibited by inhibition of dihydrofolate reductase, which provides reduced folates for purine synthesis. The liquor half-time is approximately 4–8 h. For this reason, a protocol has been established, where MTX is injected twice weekly for treatment induction and, when required, weekly for consolidation.
MTX 是葉酸拮抗劑。
- 10 or 12 mg twice a week for four weeks or until cytology becomes negative for malignant cells.
- leucovorin (10 mg twice daily for three days
- To minimize the risk of systemic methotrexate toxicity
- to all patients to minimize myelosuppression related to methotrexate leaving the CSF and entering the bloodstream before being eliminated by the kidneys.
Side effects
- Renal insufficiency, resulting in delayed excretion of methotrexate
- Pleural effusion or ascites, which can accumulate methotrexate and then slowly release drug into the systemic circulation (the “third space” effect)
- Abnormal CSF flow, prolonging release of methotrexate from the CSF into the systemic circulation
from: Treatment of systemic lupus erythematosus
- Arthritis (preferred over MMF/AZA)
- Skin disease & serositis
- Myelosuppression, alopecia, hepatotoxicity, stomatitis,
- pneumonitis, teratogen