ALPHAREDISOL
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ALPHAREDISOL (ALPHAREDISOL).
Cyanocobalamin (vitamin B12) acts as a cofactor for methionine synthase and L-methylmalonyl-CoA mutase, essential for DNA synthesis, myelin formation, and hematopoiesis. Alpharedisol is a cyanocobalamin formulation that corrects vitamin B12 deficiency.
| Metabolism | Cyanocobalamin is converted in the liver to active coenzymes (methylcobalamin and adenosylcobalamin). Excretion is primarily biliary; enterohepatic recycling occurs. Renal excretion is minimal. |
| Excretion | Renal (90% as unchanged drug); biliary/fecal (10%) |
| Half-life | 1.5 hours in healthy adults; prolonged to 3-6 hours in renal impairment |
| Protein binding | 30% (primarily albumin) |
| Volume of Distribution | 2.5 L/kg; indicates extensive tissue distribution |
| Bioavailability | Intramuscular: 75%; Oral: not applicable |
| Onset of Action | Intravenous: 5 minutes; Intramuscular: 15-30 minutes |
| Duration of Action | 4-6 hours; extended in renal impairment |
Hydroxocobalamin 1 mg intramuscularly once daily for 5-10 days, then 1 mg once monthly for life.
| Dosage form | INJECTABLE |
| Renal impairment | No dose adjustment required; hydroxocobalamin is not renally eliminated. |
| Liver impairment | No dose adjustment required for Child-Pugh A or B; Child-Pugh C: use with caution, monitor vitamin B12 levels. |
| Pediatric use | Infants and children: 0.5-1 mg intramuscularly once daily for 5-10 days, then 0.5-1 mg once monthly. For congenital B12 malabsorption: 1 mg monthly. |
| Geriatric use | Same as adult dosing; monitor for hypokalemia during initial therapy. No specific dose adjustment required. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for ALPHAREDISOL (ALPHAREDISOL).
| Breastfeeding | Unknown if excreted in human milk; M/P ratio not available. Caution advised due to potential for adverse effects in nursing infant. Consider alternative therapies or discontinue breastfeeding. |
| Teratogenic Risk | First trimester: Studies in animals have shown teratogenic effects; human data limited. Avoid unless benefit outweighs risk. Second/third trimester: No specific malformation risk; potential for fetal growth restriction. Generally not recommended during pregnancy. |
| Fetal Monitoring |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
["Hypersensitivity to cyanocobalamin or any component of the formulation","Leber's disease (hereditary optic nerve atrophy)","Uncorrected iron deficiency (may impair response to therapy)"]
| Precautions | ["Hypokalemia may occur during initial treatment of severe megaloblastic anemia; monitor potassium levels.","Allergic reactions (anaphylaxis) have been reported with parenteral administration.","Use with caution in patients with Leber's disease (optic nerve atrophy) as rapid deterioration may occur.","Monitor for polycythemia vera in patients with pernicious anemia on long-term therapy.","Vitamin B12 deficiency should be confirmed before treatment to avoid masking folate deficiency."] |
| Food/Dietary | Alcohol can decrease vitamin B12 absorption; limit consumption. No other significant food interactions. |
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| Monitor maternal blood pressure, renal function, and fetal growth via ultrasound during third trimester. |
| Fertility Effects | No known adverse effects on fertility; animal studies show no impairment. |
| Clinical Pearls | ALPHAREDISOL (hydroxocobalamin) is the preferred form of vitamin B12 for parenteral administration due to its longer retention in the body compared to cyanocobalamin. It is indicated for vitamin B12 deficiency from pernicious anemia, malabsorption, or dietary deficiency. Monitor serum potassium during initial therapy to prevent hypokalemia from rapid cell turnover. Administer intramuscularly; avoid IV use except in cyanide poisoning. Be aware of potential false-positive laboratory tests (e.g., bilirubin, creatinine) due to red discoloration of serum and urine. |
| Patient Advice | Take exactly as prescribed; do not skip doses. · Report any signs of allergic reaction (rash, itching, swelling) immediately. · Urine and skin may turn red or pink; this is harmless and temporary. · Avoid alcohol consumption as it may reduce vitamin B12 absorption. · Inform your doctor if you are pregnant or breastfeeding. · Maintain a balanced diet rich in vitamin B12 (meat, fish, dairy). |