RETACRIT
Clinical safety rating
cautionComprehensive clinical and safety monograph for RETACRIT (RETACRIT).
RETACRIT (epoetin alfa-epbx) is a recombinant human erythropoietin that stimulates erythropoiesis by binding to and activating the erythropoietin receptor on erythroid progenitor cells, promoting their survival, proliferation, and differentiation into mature red blood cells.
| Metabolism | Epoetin alfa-epbx is a protein; metabolism is expected to involve proteolytic degradation via catabolic pathways, similar to endogenous erythropoietin. No specific metabolic enzymes have been identified; clearance is primarily through receptor-mediated uptake and proteolysis. |
| Excretion | Primarily hepatic metabolism; ~10% excreted unchanged in urine, remainder via feces as metabolites. |
| Half-life | Terminal elimination half-life is ~2.5-4.5 hours following intravenous administration; shorter in children; prolonged in hepatic impairment. |
| Protein binding | Primarily binds to transferrin; iron is 100% bound to transferrin after dissociation from complex. |
| Volume of Distribution | Vd is approximately 0.067-0.22 L/kg; reflects distribution into plasma and extracellular fluid; limited tissue penetration initially. |
| Bioavailability | Not orally bioavailable; administered intravenously (100% bioavailability for IV route). |
| Onset of Action | Intravenous: within 5-15 minutes; oral: not applicable for this parenteral iron agent. |
| Duration of Action | Clinical effect typically persists for 24-48 hours; hemoglobin response may be seen within 1-2 weeks after full dosing. |
| Molecular Weight | 30400 |
50-100 IU/kg intravenously or subcutaneously three times weekly; initial dose 50 IU/kg three times weekly, titrated to target hemoglobin 10-12 g/dL.
| Dosage form | INJECTABLE |
| Renal impairment | For CKD patients, epoetin alfa dosing is independent of GFR; adjust based on hemoglobin response. No specific GFR-based dose adjustments, but start at 50-100 IU/kg three times weekly for dialysis patients. |
| Liver impairment | No specific Child-Pugh based adjustments. Use with caution in severe hepatic impairment; monitor for adverse effects. |
| Pediatric use | 0.5-50 IU/kg subcutaneously or intravenously three times weekly, titrated to target hemoglobin. For pediatric CKD, initial dose 50 IU/kg three times weekly. |
| Geriatric use | No specific dose adjustment; initiate at lower end of dosing range (50 IU/kg three times weekly) and titrate slowly, monitoring for hypertension and thrombotic events. |
| 1st trimester | Limited data in pregnant women. Retacrit (epoetin alfa) is a recombinant erythropoietin; animal studies not fully conclusive. Use only if clearly needed. Consider risk of increased blood viscosity. |
| 2nd trimester | May be used for treatment of anemia in pregnant women if benefit outweighs risk. Monitor hemoglobin closely to avoid excessive levels and potential thrombotic events. No human teratogenicity data. |
| 3rd trimester | May be used for anemia in third trimester; monitor for hypertension and thromboembolic events. Use lowest effective dose. No known fetal risk, but lack of large studies. |
Clinical note
Comprehensive clinical and safety monograph for RETACRIT (RETACRIT).
| Placental transfer | Epoetin alfa crosses the placenta minimally based on its molecular weight (30.4 kDa) and protein structure. Animal studies show limited transfer; human data are limited but suggest low transfer. |
| Breastfeeding | Epoetin alfa is a large glycoprotein (MW ~30.4 kDa) and is unlikely to be excreted into breast milk in significant amounts due to its size and limited oral bioavailability. However, no specific data on Retacrit in breastfeeding women. Caution is advised; consider risk versus benefit. |
| Lactation Rating | L3 (Moderately Safe) |
| Teratogenic Risk | Retacrit (epoetin alfa-epbx) is a recombinant human erythropoietin. In animal studies, epoetin alfa did not demonstrate teratogenicity at clinically relevant doses. However, there are no adequate and well-controlled studies in pregnant women. Potential fetal risks include hypertension and thromboembolic events secondary to maternal polycythemia. Use during pregnancy only if clearly needed and if the potential benefit justifies the potential risk to the fetus. |
| Fetal Monitoring | Monitor hemoglobin concentration weekly until stable, then periodically. Monitor blood pressure frequently during therapy. Monitor for signs of thrombotic events. In pregnant women, monitor for worsening hypertension, preeclampsia, and thromboembolic events. Consider fetal monitoring (e.g., ultrasound for growth) in women with chronic kidney disease or significant anemia. |
| Fertility Effects | No specific studies on fertility effects of Retacrit have been conducted. In animal studies with epoetin alfa, no effects on fertility were observed at clinically relevant doses. Anemia itself may impair fertility; correction of anemia with Retacrit may improve fertility in affected individuals. |
■ FDA Black Box Warning
WARNING: INCREASED RISK OF DEATH, MYOCARDIAL INFARCTION, STROKE, VENOUS THROMBOEMBOLISM, THROMBOSIS OF VASCULAR ACCESS AND TUMOR PROGRESSION OR RECURRENCE. Chronic Kidney Disease: In controlled trials, patients experienced greater risks for death, serious adverse cardiovascular reactions, and stroke when administered erythropoiesis-stimulating agents (ESAs) to target a hemoglobin level of 13 g/dL or greater. No trial has identified a hemoglobin target level, ESA dose, or dosing strategy that does not increase these risks. Use the lowest dose sufficient to reduce the need for red blood cell transfusions. Cancer: ESAs shortened overall survival and/or increased the risk of tumor progression or recurrence in clinical studies of patients with breast, non-small cell lung, head and neck, lymphoid, and cervical cancers. To decrease these risks, as well as the risk of serious cardiovascular and thromboembolic reactions, use the lowest dose needed to avoid red blood cell transfusions. Use ESAs only for anemia from myelosuppressive chemotherapy. ESAs are not indicated for patients receiving myelosuppressive chemotherapy when the anticipated outcome is cure. Discontinue following the completion of a chemotherapy course. Perisurgery: Due to increased risk of deep venous thrombosis (DVT), use prophylactic anticoagulation and consider whether benefit of transfusion reduction outweighs increased risk of post-operative thrombotic/vascular events.
| Serious Effects |
Uncontrolled hypertensionHypersensitivity to epoetin alfa or any componentPure red cell aplasia (PRCA) due to prior erythropoietin therapySevere coronary artery disease, peripheral vascular disease, or cerebrovascular disease (when hemoglobin >12 g/dL)
| Precautions | Increased mortality, myocardial infarction, stroke, and thromboembolism, Increased risk of thrombosis of vascular access, Increased mortality and/or tumor progression in cancer patients, Hypertension, Seizures, Pure red cell aplasia (PRCA) due to anti-erythropoietin antibodies, Serious allergic reactions, Possible worsening of anemia due to antibody-mediated PRCA, Risk of cardiovascular events when hemoglobin exceeds 11 g/dL, Need for iron supplementation, Monitoring of hemoglobin and blood pressure |
| Food/Dietary | No specific food interactions. Maintain adequate iron intake; consider dietary sources of iron (e.g., red meat, leafy greens) if not on supplements. No restrictions with alcohol or other foods. |
| Clinical Pearls | Retacrit (epoetin alfa-epbx) is a biosimilar to Epogen/Procrit. Monitor hemoglobin weekly until stable, then monthly; target Hb 10-12 g/dL. Do not use to replace urgent transfusions. Iron stores must be adequate; check ferritin and transferrin saturation. Increased risk of thrombotic events, especially in patients with cardiovascular disease. Do not shake vial; use one vial per dose; discard unused portion. Administer subcutaneously or intravenously; rotate injection sites. |
| Patient Advice | This medication helps your body make more red blood cells to treat anemia. · You will have regular blood tests to check your hemoglobin levels and iron stores. · Do not miss scheduled appointments for monitoring; call your doctor if you have symptoms of a blood clot (chest pain, sudden shortness of breath, leg swelling). · It is important to take iron supplements as prescribed while on this medication. · Store Retacrit in the refrigerator; do not freeze or shake the vial. · Report any signs of allergic reaction (rash, itching, swelling). |
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