Erythropoietin agents
Epoetin alfa and darbepoetin alfa are glycoproteins that stimulate RBC production (erythropoiesis).
Pharmacokinetics
Epoetin alfa and darbepoetin alfa may be given subQ or I.V. After subQ administration, serum levels of epoetin alfa peak in 5 to 24 hours, while serum levels of darbepoetin alfa peak in 24 to 72 hours.
The circulating half-life of epoetin alfa is also shorter at 4 to 13 hours, compared to 49 hours for darbepoetin alfa. The therapeutic effect of these agents lasts for several days after administration.
Pharmacodynamics
Epoetin alfa and darbepoetin alfa boost the production of erythropoietin, thus stimulating RBC production in bone marrow. Normally, erythropoietin is formed in the kidneys in response to hypoxia (reduced oxygen) and anemia.
Patients with conditions that decrease production of erythropoietin typically develop normocytic anemia. This anemia can usually be corrected after 5 to 6 weeks of treatment with an erythropoietin agent.
Pharmacotherapeutics
Epoetin alfa is used to:
- treat patients with anemia associated with chronic renal failure
- treat anemia associated with zidovudine therapy in patients with human immunodeficiency virus infection
- treat anemia in cancer patients receiving chemotherapy
- reduce the need for allogenic blood transfusions in surgical patients.
Darbepoetin alfa is used to treat anemia associated with chronic renal failure.
Drug interactions
No known drug interactions exist with either drug, although they can cause some adverse reactions.
Warning!
Adverse reactions to erythropoietin agents
Hypertension is the most common adverse reaction. Other adverse reactions may include:
- headache
- joint pain
- nausea
- edema
- fatigue
- diarrhea
- vomiting
- chest pain
- skin reactions at the injection site
- weakness
- dizziness.
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