In March, the Food and Drug Administration (FDA) issued a warning about the use of Aranesp, Epogen, and Procrit in all patients. These drugs are called erythropoiesis-stimulating agents (ESAs). They stimulate a patient's bone marrow to produce more red blood cells and are given to patients to reduce the need for blood transfusions. ESAs are used to treat anemia in a variety of conditions, including anemia caused by chronic kidney failure, cancer, and treatment with Retrovir (AZT, zidovudine) in HIV patients. These drugs are sometimes also given to patients before they have major surgery to reduce the need for blood transfusions.

The warnings advise health-care providers to monitor red blood cell levels (hemoglobin levels) and to adjust the dose of ESAs to maintain the lowest hemoglobin level necessary to avoid a blood transfusion. Recent studies show that when patients with chronic kidney failure receive a higher than recommended dose of an ESA, they are more likely to die or experience blood clots, strokes, heart failure, and heart attacks. Other studies have reported that patients with head and neck cancer receiving radiation therapy had taster tumor growth. In addition, cancer patients not receiving chemotherapy died sooner and did not have any fewer blood transfusions when ESAs were given according to the dosing recommendations for cancer patients receiving chemotherapy. Finally, patients scheduled for surgery who received ESAs to reduce blood transfusions during and alter surgery had more blood clots than those not given an ESA.

While ESAs appear to be safe and effective when used at the recommended dose, anyone using these drugs must be aware that they are at increased risk of death and of serious heart complications, including stroke, heart attack, and blood clots in the heart or lungs. The warnings recommend that patients and their health-care providers carefully consider the risks of ESAs and the risks of red blood cell transfusions (an alternative treatment for anemia) before making a decision to use ESAs.