fluorouracil

= 5FU; n.

a drug that prevents cell growth (see antimetabolite) and is used in the treatment of solid tumours, such as cancers of the digestive system and breast (see also folinic acid). It is usually administered by intravenous infusion or injection; it is not well absorbed when taken by mouth, but oral fluoropyrimidines (e.g. capecitabine and tegafur/uracil) are converted to 5FU in the liver. Side-effects may include digestive and skin disorders, mouth ulcers, hair loss, nail changes, and blood disorders (see myelosuppression). Fluorouracil is also applied as a cream (Efudix) to treat certain skin conditions, including skin cancer.