Methotrexate
Ectopic pregnancy: single IM dose 50 mg/m². In rheumatology it's given once weekly; daily dosing errors kill.
On this page
Dose
| Indication | Dose |
|---|---|
| Ectopic pregnancy (selected) | 50 mg/m² IM single dose; hCG on days 4 and 7 |
| Rheumatoid arthritis, psoriasis | 7.5–25 mg once weekly, with folic acid on another day |
Ectopic eligibility (typical)
Stable, no significant pain, unruptured, mass under 35 mm, no fetal heartbeat, hCG under 1,500–5,000 IU/L, able to return for follow-up.
Cautions
- Avoid alcohol, NSAIDs, trimethoprim; check FBC, LFTs and kidney function.
- Avoid pregnancy for 3–6 months after.
- Weekly dosing must be clearly written; daily dosing causes fatal bone marrow suppression.
Frequently asked questions
What should hCG do after methotrexate for an ectopic?
Fall by at least 15% between day 4 and day 7; if not, a second dose or surgery is considered.
Used in these guides
Sources
Doses on this page are typical doses from the sources above. Always confirm with a current drug reference, the product leaflet and your hospital protocol, especially in children, pregnancy and kidney or liver disease.
For FCPS Part 1
Revising for FCPS Part 1? Methotrexate is covered in our textbook chapter Chemotherapy in gynaecology, with practice MCQs.