Erythropoiesis-Stimulating Agents and Hematinics for Treatment of Anemia
Product | Role in RBC Synthesis | Indications for Supplementation | Dosing | Disadvantages/Adverse Effects |
|---|---|---|---|---|
Erythropoiesis-Stimulating Agents | ||||
Epoetin alfa (recombinant human erythropoietin) | Mimics endogenous erythropoietin, stimulating bone marrow precursors | Anemia associated with chronic kidney disease (decreased erythropoietin production) | Dogs and cats: Initial dose 100 U/kg, SC, 3 times/wk, until low end of target PCV range is reached; then frequency decreased to q 7 d | Autoantibody development leading to treatment resistance and worsening anemia (pure red cell aplasia) is the most serious adverse effect Concurrent iron supplementation is recommended to decrease the risk of iron deficiency |
Darbepoetin alfa | Synthetic form of erythropoietin, with same action and 3-fold longer half-life | Anemia associated with chronic kidney disease (decreased erythropoietin production) Its use has now superseded that of epoetin, because of decreased frequency of dosing required and evidence suggesting decreased frequency of pure red cell aplasia | Dogs: Initial dose 0.45–1.5 mcg/kg, SC, q 7 d until low end of target PCV range is reached Cats: Initial dose 0.7–1.8 mcg/kg, SC, q 7 d until low end of target PCV range is reached When target PCV is reached, dosing interval is extended as tolerated (eg, to every 2–3 wk) | Same effects as for epoetin Less common adverse effects of both epoetin and darbepoetin include injection site reactions, vomiting, diarrhea, polycythemia, hypertension, and seizures |
Hematinics | ||||
Vitamin B12 (cobalamin, cyanocobalamin) | Essential for DNA synthesis and RBC maturation in the bone marrow Deficiency results in macrocytic anemia (also called megaloblastic anemia) | Malabsorption from the GI tract due to disease or drugs, such as chronic enteropathy (eg, inflammatory bowel disease), ileectomy, gastrectomy, exocrine pancreatic insufficiency Chronic administration of antacids (H2-receptor antagonists or proton-pump inhibitors) | Parenteral: 20–50 mcg/kg, SC, q 7 d for 4–6 wk; then monthly Oral: 50 mcg/kg, PO, q 24 h for at least 12 wk | No major toxicity |
Folic acid (folate, vitamin B9) | Essential for DNA and RNA synthesis Deficiency results in macrocytic anemia | Dietary deficiency Malabsorption (duodenum and proximal jejunum) Liver disease (decreased storage) Interfering drugs (eg. methotrexate, potentiated sulfonamides) Chronic blood loss | Varied dosing reported Dogs: 5 mg, PO, q 24 h for 1 mo Cats: 2.5 mg/cat, PO, q 24 h for 1 mo Injectable (both dogs and cats): 1–5 mg, SC, q 7 d for 1 mo | No major toxicity |
Iron | Necessary for hemoglobin formation Deficiency results in microcytic, hypochromic anemia | Dietary deficiency Iron depletion (eg, chronic blood loss) | Parenteral preparations are indicated for initial treatment or if oral preparations cannot be tolerated or are not feasible (eg, in neonatal pigs) Iron dextrans (dogs 10–20 mg/kg, IM [maximum 300 mg/dog]; cats 10 mg/kg, IM) once, or continue monthly in absence of oral supplementation Ferrous sulfate (dogs: 100–300 mg/d; cats: 50–100 mg/d), although other ferrous salts can be used Treatment for several months is often indicated | Adverse effects are dose-related GI upset can be decreased by administration with food At toxic doses, iron can cause potentially life-threatening GI, cardiovascular, and hepatic dysfunction Pain on IM injection |