Darbepoetin Alfa
Darbepoetin alfa is a synthetic, long-acting erythropoiesis-stimulating agent (ESA). It is a 165-amino acid protein produced via recombinant DNA technology in Chinese hamster ovary cells. **Clinical Pearl**: Compared to epoetin alfa (rHuEPO), darbepoetin contains two additional N-linked carbohydrate chains. This structural modification increases its molecular weight and dramatically increases its metabolic stability and half-life, allowing for less frequent dosing (e.g., once weekly instead of three times weekly). It is primarily used off-label in veterinary medicine to manage non-regenerative anemia associated with chronic kidney disease (CKD) in dogs and cats. Theoretically, the extra carbohydrate shielding may make it less immunogenic than epoetin alfa, potentially reducing the risk of pure red cell aplasia (PRCA), though this remains unproven in veterinary patients.
Mecanismo: Darbepoetin alfa mimics endogenous erythropoietin by binding to the **erythropoietin receptor (EpoR)** on the surface of erythroid progenitor stem cells in the bone marrow. * Binding induces receptor dimerization → activates the **JAK2/STAT5** intracellular signaling pathway. * This cascade → inhibits apoptosis of progenitor cells → stimulates their proliferation and differentiation into mature **red blood cells (RBCs)**. * The increased RBC mass subsequently raises the packed cell volume (PCV) and improves tissue oxygenation.
Dosificación por especie
- Anemia of chronic kidney disease · 0.45 micrograms/kg · SC/IV · once weekly · Initial human dose. Adjust using clinical judgment and careful monitoring. Alternatively, convert from epoetin alfa: Total weekly dose of epoetin in Units divided by 200 = once weekly dose in micrograms darbepoetin.
- Anemia of chronic kidney disease · 0.45 micrograms/kg · SC/IV · once weekly · Initial human dose. Adjust using clinical judgment and careful monitoring. Alternatively, convert from epoetin alfa: Total weekly dose of epoetin in Units divided by 200 = once weekly dose in micrograms darbepoetin.
Las dosis son una referencia clínica para médicos veterinarios. Confirme siempre con la información vigente del producto y el paciente individual.
Vías de administración
Contraindicaciones
- Patients with documented anti-rHuEPO antibodies
- Uncontrolled hypertension
- Hypersensitivity to darbepoetin or excipients in the formulation
Efectos adversos
- Anti-rHuEPO antibody formation leading to pure red blood cell aplasia (PRCA)
- Hypertension
- Seizures
- Iron deficiency (due to rapid RBC production depleting iron stores)
Interacciones farmacológicas
- Androgens · May increase the sensitivity of erythroid progenitors (interaction has been used for therapeutic effect with epoetin)
- Desmopressin · Can decrease bleeding times when used concurrently with erythropoietin agents
Monitoreo
- PCV/Hematocrit (check before each re-dosing)
- Iron stores (supplement with iron if necessary)
- Blood pressure
Sobredosis
Little information is available in veterinary species. In humans, therapeutic dosages of up to 8 micrograms/kg every week for 12 weeks have been administered. Polycythemia (excessive red blood cells) is possible with overdosage, and therapeutic phlebotomy may be required to reduce blood viscosity.
La referencia de fármacos de VetSheet está destinada a médicos veterinarios como apoyo a la decisión clínica; no sustituye el juicio profesional ni la información vigente del fabricante.