Darbepoetin alfa is a drug, a synthetic hormone, that increases red blood cell levels, and is used to treat anemia and related conditions. It is in the same class of drugs as erythropoietin (EPO) and competes for the same market.

Its brand name is Aranesp, marketed by Amgen. It was approved in September 2001 by the Food and Drug Administration for treatment of patients with chronic renal failure by intravenous or subcutaneous injection.

It is produced in modified CHO cells. It differs from endogenous erythropoietin by containing two more N-linked oligosaccharide chains. It is an erythropoiesis stimulating 165-amino acid protein.

Like EPO its use increases the risk of cardiovascular problems, including cardiac arrest, seizures, arrhythmia or strokes, hypertension and hypertensive encephalopathy, congestive heart failure, vascular thrombosis or ischemia, myocardial infarction and edema. Pre-existing hypertension contra-indicates the use of darbepoetin as does existing a hematologic disease. Adverse reactions can include hypotension fever, chest pains, nausea and myalgia.

Also like EPO it has the potential to be abused by athletes seeking an advantage. Its use during the 2002 Winter Olympic Games to improve performance led to the disqualification of cross-country skiers Larissa Lazutina and Olga Danilova of Russia and Johann Mühlegg of Spain from their final races.