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ANTINEOPLASTIC AND IMMUNOMODULATING AGENTS › IMMUNOSUPPRESSANTS › IMMUNOSUPPRESSANTS › Other immunosuppressants
methotrexate
L04AX03
Forms & Strengths
- Tablets: 2.5mg, 5mg, 7.5mg, 10mg, 15mg
- Injection: 25mg/mL, 50mg/2mL, 100mg/4mL
- Oral solution: 2.5mg/mL
- Powder for injection: 1g, 5g, 50mg
- Subcutaneous injection: 25mg/mL, 50mg/2mL
Adult Dosing
- Rheumatoid arthritis: 7.5-20mg/week
- Psoriasis: 10-25mg/week
- Cancer: varied, depending on type and stage
Pediatric Dosing
- Juvenile idiopathic arthritis: 5-15mg/m²/week
- Acute lymphoblastic leukemia: 2.5-5mg/m²/dose
- dosage adjusted based on age, weight, and renal function
Indications
- Rheumatoid arthritis
- Psoriasis
- Polyarticular juvenile idiopathic arthritis
- Acute lymphoblastic leukemia
- Breast cancer
- Lung cancer
- Osteosarcoma
Mechanism of Action
- Inhibits dihydrofolate reductase
- Interferes with DNA synthesis
- Suppresses immune system activity
Contraindications
- Pregnancy and breastfeeding
- Severe liver or kidney disease
- Blood dyscrasias
- Active infections
- Hypersensitivity to methotrexate
Adverse Reactions
- Myelosuppression
- Gastrointestinal toxicity
- Hepatotoxicity
- Pulmonary fibrosis
- Nephrotoxicity
- Neurotoxicity
- Mucositis
- Immunosuppression
Drug Interactions
- Increased toxicity with NSAIDs
- Reduced efficacy with folic acid
- Increased risk of hepatotoxicity with acetaminophen
- Interactions with other immunosuppressants and antifolates
- Increased risk of myelosuppression with co-trimoxazole
Curated Content: Needs Vetting Before Put to Clinical Use