Methotrexate: Uses, Side Effects, and Safe Use
Methotrexate is a prescription medicine that reduces inflammation and slows immune activity. It is used for conditions such as rheumatoid arthritis and psoriasis, and certain forms of methotrexate are used in cancer treatment. It is available as tablets and as an injection, and the dosing schedule differs by condition and formulation.
Methotrexate can help control inflammatory diseases, but it may affect blood counts, liver function, and the lungs. Take it exactly as prescribed, usually once weekly for inflammatory arthritis, and ask your doctor or pharmacist if you have any questions.
This medication carries a boxed (black box) warning — the strongest type of FDA warning. Review the full prescribing information before use.
Key facts at a glance
- ATC
- L04AX03
- Generic
- Methotrexate
- Class
- dmard
- Brands
- Rheumatrex, Trexall
- Availability
- rx
- Pregnancy
- X
- Lactation
- unsafe
- Half-life (h)
- 8
- Routes
- oral, sc, im, iv
- Forms
- tablet, injection
- Regions
- CN, US, EU, JP
- Monitoring
- liver-function, blood-count, renal-function
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Dosage and administration
- Usual dose
- 15mg once weekly
- Maximum
- consult physician
- Frequency
- once weekly
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 0.3mg per kg once weekly
- Maximum
- consult physician
- Frequency
- once weekly
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 7.5mg once weekly
- Maximum
- consult physician
- Frequency
- once weekly
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
Overdose information
Special Populations
8 groupspregnancy
first trimesteravoid use
contraindicated during pregnancy due to high risk of fetal malformations and embryotoxicity
discontinue before conception if possible, fetal ultrasound monitoring if exposed
Use of this medication in this population requires careful consideration of risks and benefits.
pregnancy
second third trimesteravoid use
contraindicated throughout pregnancy due to risk of fetal toxicity and growth restriction
regular fetal growth monitoring, ultrasound assessments
Use of this medication in this population requires careful consideration of risks and benefits.
lactation
n adiscontinue breastfeeding
methotrexate passes into breast milk and can cause serious toxicity in infants
not applicable - breastfeeding should be discontinued
Use of this medication in this population requires careful consideration of risks and benefits.
geriatric
elderlyreduce starting dose
start at lower doses and titrate slowly, increased risk of renal impairment and myelosuppression in elderly
close monitoring of renal function, CBC, and liver enzymes more frequently
Use with caution and monitor for adverse effects.
pediatric_age
children adolescentsweight-based dosing
used for juvenile idiopathic arthritis and certain pediatric malignancies at reduced doses
regular CBC, renal function, and liver function tests, growth monitoring
Use with caution and monitor for adverse effects.
renal_impairment
mild moderatereduce dose by 25-50%
methotrexate is primarily renally eliminated; dose reduction required based on creatinine clearance
monitor renal function and methotrexate levels closely
Use with caution and monitor for adverse effects.
renal_impairment
severeavoid use
contraindicated in patients with severe renal impairment (CrCl < 30 mL/min)
regular monitoring of renal function and methotrexate serum levels
Use of this medication in this population requires careful consideration of risks and benefits.
hepatic_impairment
mild moderateuse with caution
avoid in significant hepatic impairment; hepatotoxicity is a known risk
frequent liver function tests, liver biopsy if long-term use anticipated
Use with caution and monitor for adverse effects.
Statistics and clinical data
FDA approval year
Original FDA approval for Methotrexate
Drug class
Pharmacological classification
Primary indications
Therapeutic indications
Mechanism of action
Pharmacological mechanism
Drug interactions
1 documented interaction(s) with other medications in this knowledge base.
NSAIDs（包括COX-2抑制剂）可通过抑制前列腺素减少肾血流量/GFR，并竞争肾小管分泌，从而降低甲氨蝶呤肾清除率，升高其血药浓度并增加毒性风险（骨髓抑制、黏膜炎、肝肾毒性）。Celecoxib对低剂量MTX的药代动力学影响相对较小，但仍属同类风险。
Contraindications
Conditions and patient states where this medication should be avoided or used with caution.
Do not use (1)
Known allergy to this medication or its components
Use caution (1)
Consult healthcare provider for benefits vs risks assessment
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed July 22, 2026. · Read our editorial policy