Tegafur with gimeracil and oteracil (Specialist drug)

How it works

Tegafur is a prodrug converted to fluorouracil, which inhibits thymidylate synthase and disrupts DNA synthesis; gimeracil slows fluorouracil breakdown to sustain levels, while oteracil reduces gastrointestinal toxicity.

Prescribing in practice

• It is contraindicated with other fluoropyrimidines and with brivudine, and patients with DPD (dihydropyrimidine dehydrogenase) deficiency are at high risk of severe, potentially fatal toxicity, so DPD status should be considered before treatment.
• Severe diarrhoea, mucositis, myelosuppression and hand-foot syndrome can occur and may require dose interruption.
• Renal impairment increases gimeracil-related toxicity, so dose and suitability must be reviewed against the SPC.

Monitoring

Monitor full blood count, renal and liver function, and for gastrointestinal and skin toxicity throughout treatment.

Counselling the patient

• Report severe diarrhoea, mouth ulcers, fever, or painful red hands and feet promptly.
• Take the medicine as directed and do not take other fluorouracil-type medicines at the same time.
• Tell your team about all other medicines, including antiviral treatments.

Evidence & guidelines

Its use in advanced gastric cancer is supported by randomised controlled trials.