阿法依泊汀 (紅血球生成素)
阿法依泊汀是一種重組人類紅血球生成素 (rHuEPO)，主要用於治療犬貓因慢性腎衰竭引起的非再生性貧血。由於在獸醫臨床上容易產生抗紅血球生成素的自體抗體（高達 20-70% 的機率），導致嚴重的難治性貧血，因此通常被視為「最後手段」。治療期間通常需要額外補充鐵質。
作用機制: Erythropoietin is an endogenous hormone primarily produced by the kidneys that regulates erythropoiesis. * **Receptor Binding:** Epoetin alfa binds to **erythropoietin receptors** on the surface of committed erythroid progenitor cells in the bone marrow. * **Proliferation & Differentiation:** This binding activates intracellular signaling pathways (such as JAK2/STAT5) → stimulates the survival, proliferation, and differentiation of red cell precursors. * **Reticulocyte Release:** It also accelerates the release of reticulocytes from the bone marrow into the systemic circulation, ultimately increasing the hematocrit and hemoglobin levels.
各物種劑量
- Adjunctive therapy for anemia associated with endstage renal disease · Initially, 100 Units/kg SC 3 times weekly (or 48.4-145 Units/kg SC 3 times a week). · SC · 3 times weekly · Ongoing · Target hematocrit is 30-40%.
- Anemia associated with endstage renal disease (PCV <20%) · 75-100 Units/kg SC three times a week until PCV is in the low normal range (35%), then reduce dose and frequency to 50-75 Units/kg two times per week. · SC · 3 times a week initially · Ongoing · Administer iron at start of regime and until appetite is good.
- Problematic clinical signs and PCV <20% · Initially, 100 Units/kg SC 3 times per week. · SC · 3 times per week · Ongoing · Provide oral supplementation with ferrous sulfate (5-50 mg per cat per day). Reduce to twice per week when target PCV (30-40%) is reached.
- Anemia · 50-150 Units/kg IM 3 times weekly; may decrease to once weekly if RBC indices are significantly improved · IM · 3 times weekly · Ongoing
- Anemia (Rabbits) · 50-150 Units/kg SC every 2-3 days until PVC is normal; then once weekly (q7 days) for at least 4 weeks · SC · every 2-3 days initially · at least 4 weeks maintenance
- Adjunctive therapy for anemia associated with endstage renal disease · Initially, 100 Units/kg SC 3 times weekly, until the bottom of the target hematocrit range of 37-45% is attained. Once attained, change to twice weekly. As hematocrit approaches upper target, reduce to once weekly. Maintenance generally 75-100 Units/kg SC 1-2 times weekly. · SC · 3 times weekly initially · Ongoing · A lower initial dosage of 50-100 Units/kg 3 times weekly may be used. Iron supplementation required.
- Adjunctive therapy for anemia associated with endstage renal disease · Initially, 48.4-145 Units/kg SC three times a week. Most dogs should be started at 97 Units/kg SC 3 times a week. · SC · 3 times a week · Ongoing · Monitor hematocrit weekly until target 37-45% is reached, then decrease to two times weekly. Oral iron supplements recommended.
劑量為合格獸醫專業人員的臨床參考。請務必對照最新藥品仿單及個別病患確認。
給藥途徑
禁忌症
- Uncontrolled hypertension
- Hypersensitivity to epoetin alfa
- Formation of significant autoantibodies with prior treatment
- Equines (not recommended for use)
不良反應
- Autoantibody formation (leading to refractory anemia)
- Systemic hypertension
- Vomiting
- Seizures
- Uveitis
- Iron depletion
- Local reactions at injection sites
- Fever
- Arthralgia
- Mucocutaneous ulcers
- Polycythemia (with chronic overdosage)
藥物相互作用
- Androgens · May increase the sensitivity of erythroid progenitors; safety of this combination is not fully determined.
- Desmopressin · Concurrent use with EPO can decrease bleeding times.
- Probenecid · Has been demonstrated to reduce the renal tubular excretion of EPO; clinical significance remains unclear.
- Iron supplements · Synergistic/Required; EPO increases demand for iron to synthesize hemoglobin for new RBCs · minor
監測
- Hematocrit / PCV (weekly to every other week initially, then every 1-2 months)
- Blood Pressure (at least monthly initially)
- Renal Function Status
- Iron status (serum iron, TIBC)
- RBC indices
過量
Acute overdoses appear to be relatively free of adverse effects. Single doses of up to 1600 Units/kg in humans demonstrated no signs of toxicity. **Chronic overdoses** may lead to polycythemia or other adverse effects. Cautious phlebotomy may be employed should polycythemia occur.
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