Effects of 5-fluorouracil on erythrocytes in relation to its cardiotoxicity: Membrane structure and functioning

In the present study, we showed that the antineoplastic drug 5-fluorouracil (5-FU) induces in vitro exposure-time/dose-dependent changes on the level of an erythrocyte's morphology, ionic balance, and membrane fluidity. These changes are partially or fully irreversible, and we suggest that they are provoked by an irreversible depletion of ATP. Because of these changes that could also occur in vivo during 5-FU infusion, a certain amount of erythrocytes with echinocytic shape and diminished ability to deliver oxygen is present in blood for longer periods of time. This renders oxygen transport and delivery more difficult, leaving the heart with an insufficient supply of oxygen, thus leading to cardiotoxicity.