Erythropoietin (EPO) is a hormone that is naturally produced by the kidneys to stimulate the production of red blood cells. It is also called haematopoietin or haemopoietin. EPO helps the body maintain a healthy amount of red blood cells (erythrocytes) . When cells in the kidneys sense that there is sufficient oxygen in the blood, they reduce the production of EPO. Certain conditions can affect how much EPO the kidneys make, leading to low levels of red blood cells or high levels of red blood cells.
EPO stimulating agents (ESAs) are recombinant versions of EPO produced pharmacologically. They are generally indicated in conditions where there is impaired red blood cell production. ESAs are used to treat anemia that results from chronic kidney disease and other anemias related to bone marrow suppression and/or failure, such as that due to radiation or chemotherapy treatment for cancer.
Some athletes improperly use synthetic EPO to boost their performance because it increases the availability of oxygen to their muscles. Excess EPO results from chronic exposure to low oxygen levels or from rare tumors that produce high levels of EPO, causing a condition known as polycythemia, which means high red blood cell count.
Erythropoietin is given as an injection under the skin (subcutaneously) to treat a low number of red blood cells (anemia) due to cancer or its treatment. There are different types of erythropoietin treatments, including epoetin alfa, epoetin beta, epoetin zeta, and darbepoetin alfa. The drug treatment is expensive and its stimulation of the bone marrow lasts only a few hours.
