Epoetins

Sialic acid is a carbohydrate that can be attached to certain molecules, e.g., epoetin alfa. 

Anemia may occur in patients with chronic renal failure as tlie result of the inability of the kidney to produce erythropoietin. Erythropoietin is a glycoprotein hormone synthesized mainly in the kidneys and used to stimulate and regulate the production of erythrocytes or red blood cells (RBCs). Failure to produce the needed erythrocytes results in anemia Two examples of drug used to treat anemia associated with chronic renal failure are epoetin alfa (Epogen) and darbepoetin alfa (Aranesp). 

Epoetin alfa (erythropoietin EPO) and darbepoetin alfa are usually well tolerated. The most common adverse reactions include hypertension, headache, tachycardia, nausea, vomiting, diarrhea, skin rashes, fever, myalgia, and skin reaction at tlie injection site. See the Summary Drug Table Drug Used in the Treatment of Anemia for more information on these drug. 

Epoetin alfa is contraindicated in patients with uncontrolled hypertension, those needing an emergency transfusion, or those with a hypersensitivity to human albumin. Darbepoetin alfa (Aranesp) is contraindicated in patients with uncontrolled hypertension or in those allergic to the drug. 

Epoetin alfa and darbepoetin alfa are used with caution in patients with hypertension, heart disease, congestive heart failure, or a history of seizures. Both of these drains are Pregnancy Category C dru and are used cautiously during pregnancy and lactation. 

When monitoring the patient taking epoetin, the nurse reportsany increase in the hematocrit of 4 points within any 2-week period because an exacerbation of hypertension is associated with an excessive rise of hematocrit. Hematocrit is decreased by decreasing or withholding the epoetin alfa dose. 

During the ongoing assessment the nurse takes the vital signs daily more frequent monitoring may be needed if die patient is moderately to acutely ill or if the patient is taking epoetin alfa (because of the increased risk of hypertension). The nurse monitors the patient for adverse reactions and reports any occurrence of adverse reactions to the primary health care provider before the next dose is due. However, the nurse immediately reports severe adverse reactions. 

EPOETIN ALFA. When epoetin alfa is administered to a patient with hypertension, die nurse monitors die blood pressure closely. The nurse reports any rise in the systolic... 

This drug is not used for treatment of severe anemia or as a substitute for emergency transfusion. However, supplemental iron maybe ordered during therapy with epoetin. 

Strict compliance with antihypertensive drug regimen is important in patients witii known hypertension during epoetin tiierapy. 

When monitoring a patient taking epoetin alfa, which of the following lab results would be most important for the nurse to report immediately ... 

Recommendations in this section may change based on the results from the recent EPO-3 trial (epoetin alfa versus placebo). A difference in red blood cell transfusion rates was not observed between groups. Epoetin alpha therapy improved survival in trauma patients. Epoetin alfa did not have a measurable clinical benefit in medical/surgical non-trauma patients. Epoetin alpha therapy was associated with an increased thrombotic event rate, particularly in patients not receiving pharmacological deep vein thrombosis prophylaxis. 

Subcutaneous (SC) administration of ESA produces a more predictable and sustained response than IV administration, and is therefore the preferred route of administration for both agents. Intravenous administration is often utilized in patients who have established IV access or are receiving hemodialysis. Starting doses of ESAs depend on the patient s Hgb level, the target Hgb level, the rate of Hgb increase and clinical circumstances.31 The initial increase in Hgb should be 1-2 g/dL (0.6206-1.2404 mmol/L) per month. The starting doses of epoetin alfa previously recommended are 80 to 120 units/kg per week for SC administration and 120 to 180 units/kg per week for IV administration, divided two to three times per week. The starting dose of darbepoetin alfa is 0.45 mcg/kg administered SC or IV once weekly (Table 23-3). 

TABLE 23-3. Estimated Starting Doses of Darbepoetin Alfa Based on Previous Epoetin Alfa Dose... 

Previous Epoetin Alfa Dose (units/week) Weekly Darbepoetin Alfa Dose (mcg/week)... 

Epoetin Alfa 4000 units intravenously every hemodialysis... 

Evaluate the proper use of epoetin and darbepoetin in anemia patients with cancer and kidney disease. 

Therapy with epoetin or darbepoetin can increase hemoglobin, decrease transfusion requirements, and improve quality of life in cancer and kidney disease patients with anemia. 

Studies have shown that in patients with chemotherapy-related anemia, therapy with erythropoietin products (epoetin-alfa and darbepoetin) can increase hemoglobin, decrease transfusion requirements, and improve quality of life.12 Epoetin is recombinant human erythropoietin, and darbepoetin is structurally similar to endogenous erythropoietin. Both bind to the same receptor to stimulate red blood cell production. Darbepoetin differs from epoetin in that it is a glycosylated form and exhibits a longer half-life in the body. The half-lives of a single subcutaneous injection of epoetin or darbepoetin in patients are roughly 27 and 43 hours, respectively. 

The National Comprehensive Cancer Network (NCCN) recommends an anemia work-up for patients with hemoglobin of less than 11 g/dL (110 g/L or 6.8 mmol/L). Patients who are symptomatic or asymptomatic with significant risk factors (e.g., extensive transfusion history, myelosuppressive chemotherapy, etc) may qualify for treatment with erythropoietic agents such as epoetin-alfa or darbepoetin. Data do not support the use of one agent over another they are both equally effective in treating this type of anemia.12 Table 63-4 provides dosing recommendations for chemotherapy-related anemia. 

Epoetin-alfa (Epogen, Procrit) Darbepoetin-alfa (Aranesp)... 

According to National Kidney Foundation guidelines for the use epoetin in patients with anemia owing to kidney disease, the subcutaneous route is preferred. However, the intravenous route is used commonly in clinical practice. 

Although EPO deficiency is the primary cause of CKD anemia, iron deficiency is often present, and it is essential to assess and monitor the CKD patient s iron status (NKF-K/DOQI guidelines). Iron stores in patients with CKD should be maintained so that transferrin saturation (TSAT) is greater than 20% and serum ferritin is greater than 100 ng/mL (100 mcg/L or 225 pmol/L). If iron stores are not maintained appropriately, epoetin or darbepoetin will not be effective, and most CKD patients will require iron supplementation. Oral iron therapy can be used, but it is often ineffective, particularly in CKD patients on dialysis. Therefore, intravenous iron therapy is used extensively in these patients. Details of the pharmacology, pharmacokinetics, adverse effects, interactions, dose, and administration of erythropoietin and iron products have been discussed previously. 

Besides anemia associated with cancer and CKD, anemia of chronic disease can result from inflammatory processes and occurs commonly in autoimmune disorders such as rheumatoid arthritis and systemic lupus erythematosus. In treating these types of anemia of chronic disease, the most important principle is treating the underlying disease. These patients also may have iron deficiency and should be treated in the manner already discussed. Erythropoietin therapy such as epoetin-alfa therapy at a dose of 150 units/kg three times a week also may be used in these patients. 

Rizzo JD, Lichtin AE, Woolf SH, et al. Use of epoetin in patients with cancer Evidence-based clinical practice guidelines of the American Society of Clinical Oncology and the American Society of Hematology. J Clin Oncol 2002 20(19) 4083-4107. 

EPOGEN Epoetin alfa Amgen also approved and marketed as PROCRIT by Ortho Biotech Anemia associated with chronic renal failure Anemia caused by chemotherapy... 

Epogen (epoetin alfa, rEPO) Anaemia associated with various medical conditions Amgen... 

Neorecormon (tradename, also known as epoetin beta) is a recombinant human EPO first approved for medical use in the EU in 1997. It is indicated for the treatment of anaemia associated with various medical conditions, most commonly chronic renal failure and cancer patients receiving chemotherapy. Neorecormon is produced by recombinant DNA technology in a CHO cell line and is manufactured as outlined in Figure 10.5. It is presented in lyophilized format at various strengths (500-10 000 IU/vial) and contains phosphate buffer, sodium chloride, calcium chloride, urea, polysorbate and various amino acids as excipients. 

Markham, A. and Bryson, H. 1995. Epoetin alfa, a review of its pharmacodynamic and pharmacokinetic properties and therapeutic use in non-renal applications. Drugs 49(2), 232-254. 

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