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DMARD (Disease-Modifying Antirheumatic Drug) / Immunosuppressant

Methotrexate (Low-dose)

Brand names: Methofar, Metoject, Maxtrex

This is low-dose methotrexate as used in rheumatology, the cornerstone weekly disease-modifying antirheumatic drug for rheumatoid arthritis, psoriatic arthritis and related inflammatory conditions, given orally or subcutaneously.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

Clinical monograph

How it works

At low weekly doses it acts mainly as an anti-inflammatory immunomodulator through adenosine-related pathways and folate antagonism, rather than the cytotoxic effect seen at high oncology doses.

Prescribing in practice

  • It is taken ONCE WEEKLY only; daily administration is a recognised, sometimes fatal, dosing error that must be guarded against at prescribing, dispensing and counselling.
  • Regular monitoring is essential for myelosuppression, hepatotoxicity and the rarer but serious methotrexate pneumonitis.
  • It is contraindicated in pregnancy and in significant renal impairment, and co-prescription with trimethoprim or co-trimoxazole can precipitate severe marrow toxicity.

Monitoring

Monitor full blood count, liver function and renal function regularly under shared care, with folic acid supplementation to mitigate side effects as set out in the SPC.

Counselling the patient

  • Take on one fixed day each week, never daily, and keep a clear record.
  • Report fever, mouth ulcers, breathlessness or unusual bleeding promptly.
  • Avoid pregnancy, moderate alcohol, and continue folic acid as directed.

Evidence & guidelines

Strong randomised evidence supports low-dose weekly methotrexate as the first-line DMARD anchoring treatment strategies in rheumatoid and psoriatic arthritis.

Reference: BSR/BHPR Guidelines for MTX; NICE NG100 RA; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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