5-FUAdrucilEfudex
How it works
Converted intracellularly to FdUMP, which inhibits thymidylate synthase; metabolites are also incorporated into RNA/DNA. Backbone drug of FOLFIRINOX / mFFX.
Bolus omitted in some modified FOLFIRINOX variants. eGFR reduction → 25–50% dose reduction. DPD screening worth raising with oncology if any history of severe fluoropyrimidine toxicity.
Dosing
Typical doses
- 400 mg/m² IV bolus D1
- 2400 mg/m² continuous infusion over 46 h
Schedule
- D1 bolus + 46 h pump (mFFX, 14-day cycle)cycle_linked
Side Effects
- •Mucositis (mouth sores)
- •Diarrhoea
- •Nausea, vomiting
- •Myelosuppression
- •Hand-foot syndrome (palmar-plantar erythrodysaesthesia)
- Severe diarrhoea / dehydration — rapidly life-threatening if untreated
- Cardiotoxicity (coronary vasospasm) — rare, higher with continuous infusion
- DPD deficiency — severe, potentially fatal toxicity; test if suggestive family/personal history
Monitoring
- FBC before each cycle
- Renal function — eGFR affects clearance
- Oral mucosa check / diarrhoea grade each visit