Repurposing drugs is the reintroduction of existing drugs into markets as treatments for conditions distinct from that which they were initially intended for. Examples of this include the use of heart medications for the treatment of erectile dysfunction, and erectile dysfunction medications for the treatment of jetlag. Fluoxetine, brand named Prozac, is an antidepressant that is widely prescribed for conditions such as obsessive-compulsive disorder and major depressive disorder. It functions by blocking the serotonin transporter, delaying the removal of serotonin, leading to prolonged sensations of happiness and satisfaction. Chronic myeloid leukaemia (CML) is a white blood cell cancer that is currently treated using a drug called Imatinib. Imatinib successfully cures 12% of patients, however 26% completely fail the treatment and 62% require lifelong Imatinib to prevent the resurgence of the disease. This clearly demonstrates the necessity of developing a new drug that would address the 88% of patients who remain uncured of CML. It has recently been demonstrated that CML cells rely on signals from the nervous system, including from the serotonin transporter, to maintain survival. It was thus theorized that blocking the serotonin transporter using fluoxetine should reduce the viability of the cells. The experiments performed demonstrate that fluoxetine eliminates more than 60% of cancer cells and combining it with the existing medications leads to significant elimination of the cancer cells, reaching up to 80%. This illustrates the possibility of repurposing fluoxetine from an antidepressant to a treatment for chronic myeloid leukaemia.