About methotrexate
Antimetabolite immunosuppressant
Used for
- Rheumatoid arthritis and other inflammatory diseases
- Severe psoriasis
- Certain cancers, including leukemia and lymphoma
Usual adult dose
Inflammatory diseases: usually 7.5–25 mg once weekly. Cancer doses vary widely by treatment plan.
Usual dose in children
Cancer doses vary by diagnosis and treatment plan; specialist dosing is required.
Common side effects
- Nausea, mouth sores, diarrhea
- Low blood counts and increased infection risk
- Liver injury
- Hair loss or rash
Important warnings
- Take only once weekly for inflammatory diseases; daily use can be fatal.
- Requires regular blood tests and monitoring of liver and kidney function.
- Can cause serious infections, lung injury, and severe liver or bone-marrow problems.
- Avoid alcohol; use caution with kidney disease, liver disease, or active infection.
Pregnancy
Can cause miscarriage and serious birth defects. Avoid during pregnancy; timing before conception depends on the condition and clinical guidance.
Breastfeeding
Generally avoid during treatment; discuss when breastfeeding can safely resume with a clinician.
Interactions
- Trimethoprim or co-trimoxazole can cause severe bone-marrow suppression.
- NSAIDs and some antibiotics can increase methotrexate toxicity.
- Live vaccines may increase infection risk.
- Alcohol and other liver-toxic medicines increase liver injury risk.
AI-generated from general medical knowledge, not from this product's official leaflet. It may be incomplete or out of date. Not medical advice — ask a pharmacist or doctor before making any decision.