5-Fluorouracil induces defects in platelet function

Platelet factor-3 (PF(3)) availability and platelet aggregation to ADP (4 micromol/l) and adrenaline (1.2 micromol/l) were evaluated in patients being treated with 5-fluorouracil (5-FU) for gastrointestinal malignancy. It produced a significant reduction in platelet aggregation and platelet factor-3 (PF(3)) availability ( P < 0.001) without being associated with thrombocytopenia. The changes in platelet aggregation occurred during the first week of chemotherapy and continued with subsequent courses. This acquired abnormality may be responsible for a haemorrhagic diathesis even without obvious thrombocytopenia. Study of platelet function is important and may be considered to assess the haematological toxicity in patients being treated with systemic 5-FU therapy.