Onco Wiki / Droga

Methotrexate

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IDDRUG-METHOTREXATE
TipoFármaco
Alegais
AmethopterinAçúcarMTXMetoblastinaOtrexupAçúcarAçúcarМетотрексат
Estadoreviewed 2026-04-26 | pending_clinical_signoff
DoençasDIS-B-ALL DIS-BURKITT DIS-NK-T-NASAL DIS-PCNSL DIS-T-ALL
FontesSRC-ESMO-BREAST-METASTATIC-2024 SRC-NCCN-BCELL-2025 SRC-NCCN-BREAST-2025

Fatos sobre as drogas

Classeantimetabolita — folato análogo (inibidor da diidrofolato-reductase)
MecanismoFolate analog; competitively inhibits dihydrofolate reductase (DHFR), blocking conversion of dihydrofolate to tetrahydrofolate. Depletes reduced folate cofactors required for thymidylate (dTMP) and purine synthesis → DNA / RNA / protein synthesis arrest, S-phase cytotoxicity. At high doses crosses the blood-brain barrier in therapeutic concentrations (basis of HD-MTX in CNS lymphoma, CNS prophylaxis, intrathecal administration). Polyglutamation in cells prolongs intra- cellular retention. Leucovorin (folinic acid) bypasses the DHFR block and is the obligatory rescue after high-dose exposure.
Dose típicaHD-MTX (CNS prophylaxis DLBCL/Burkitt): 3-3.5 g/m² IV over 2-4 h with leucovorin rescue + urinary alkalinization (sodium bicarbonate to urine pH ≥7) + hydration 3 L/m²/day. R-MPV (PCNSL induction): 3.5 g/m² IV over 2 h every 14 days × 5 cycles. MATRix (PCNSL induction): 3.5 g/m² day 1 + cytarabine + thiotepa + rituximab × 4 cycles. Intrathecal (CNS prophylaxis ALL / aggressive lymphoma): 12-15 mg per dose (lumbar) or 15 mg per dose (Ommaya) per protocol schedule. GVHD prophylaxis post allo-SCT (mini-MTX): 15 mg/m² IV day 1, 10 mg/m² IV days 3, 6, 11. CMF breast (historical): 40 mg/m² IV days 1, 8 of 28-day cycle. Low-dose oral (RA, psoriasis): 7.5-25 mg PO weekly.
Ucrânia registadaVerdade
NSZU reembolsadoVerdade
Ucrânia verificada pela última vez2026-04-27

Avisos

Notas

HD-MTX (≥1 g/m²) protocol essentials: alkalinize urine to pH ≥7 (sodium bicarbonate IV); hydrate 3 L/m²/day starting 12 h pre-dose; monitor MTX levels at 24, 48, 72 h post-dose with target <0.1 µM at 72 h; continue leucovorin rescue (15 mg/m² IV q6h, escalate per nomogram if level elevated) until MTX <0.05 µM. Glucarpidase (Voraxaze) is the rescue agent for delayed clearance / AKI: rapidly hydrolyzes MTX to inactive metabolites. Pleural effusion / ascites must be fully drained before HD-MTX (third-spacing causes prolonged toxic exposure). Avoid TMP-SMX, NSAIDs, PPIs around HD-MTX dosing. Intrathecal MTX must use preservative-free formulation; leucovorin should NOT be given systemic- ically to rescue intrathecal MTX (it does not enter CSF in adequate concentration but can rescue systemic effects). For breast cancer, CMF largely supplanted by anthracycline + taxane regimens; retained for cardiac contraindication scenarios.

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