This is a prodrug that is converted to fluorouracil in body tissues following oral administration.

Indications: it is given by mouth for the treatment of metastatic breast and colorectal cancer.

Cautions: should be used with care in patients with renal impairment; doses should be reduced in moderate renal impairment.

Contra-indications: in patients with severe hepatic and renal impairment (creatinine clearance below 30ml/minute); pregnancy; breast feeding.

Side effect: diarrhoea, nausea and vomiting, stomatitis, palmer-plantar syndrome (erythema and desquamation of hands and feet), dermatitis, and bone-marrow depression have all been reported. Hyperbilirubinaemia has occurred. Dose: Adult over 18 years, 1.25 g/m2 twice daily for 14 days; subsequent courses repeated after a 7-day interval.