Hydroxocobalamin Injection (B12)
1 mg/mL
Size: 30 mLHydroxocobalamin is a naturally occurring form of vitamin B12 that is converted within the body to metabolically active cobalamin coenzymes. Vitamin B12 supports normal red blood cell formation, DNA synthesis, cellular metabolism, and the development, myelination, and function of the nervous system [1–4].
Sterile Hydroxocobalamin Injection is supplied as a 1 mg/mL, preservative-containing solution in a 30 mL multiple-dose vial for intramuscular administration by licensed healthcare professionals. The presentation is designed for office or clinical use under appropriate medical supervision [1].
Parenteral administration bypasses gastrointestinal absorption and may be appropriate when oral administration is unsuitable, absorption is impaired, or a clinician-directed protocol requires injectable vitamin B12. Dose, frequency, and duration should be individualized according to the underlying cause of deficiency, laboratory findings, clinical condition, and treatment response [1–3].
More About This Product
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• Concentration: 1 mg/mL
• Volume: 30 mL Multi-Dose Vial
• Route of Administration: Intramuscular (IM) Use.
• Dosage form: Sterile, preservative-containing injectable solution
• Administration setting: Office or clinical use; for administration by licensed healthcare professionals
Each mL contains hydroxocobalamin 1 mg, benzyl alcohol 0.9%, sodium chloride 9 mg, and Sterile Water for Injection. The pH is adjusted to 4.0–7.5 with hydrochloric acid and/or sodium hydroxide [1].
Administer only by the intramuscular route. Select an appropriate injection site, avoid direct injection into blood vessels or peripheral nerves, and rotate sites when repeated administration is required [1].
The solution should appear clear and red. Do not use if it is cloudy, unexpectedly discolored, contains visible particulate matter, or if the vial or closure is damaged. Use strict aseptic technique during every vial entry, withdrawal, and administration [1].
Hydroxocobalamin is formulated as a sterile parenteral solution utilized in clinical settings to treat and prevent vitamin B12 deficiency [3]. Adherence to strict aseptic technique is required during vial puncture and administration.
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Hydroxocobalamin is converted intracellularly to methylcobalamin and adenosylcobalamin. Methylcobalamin serves as a cofactor for methionine synthase, supporting the conversion of homocysteine to methionine and the regeneration of tetrahydrofolate required for nucleotide synthesis and normal hematopoiesis [2–4].
Adenosylcobalamin serves as a cofactor for methylmalonyl-CoA mutase, which converts methylmalonyl-CoA to succinyl-CoA. Impairment of these vitamin B12-dependent pathways contributes to the hematologic, metabolic, and neurologic manifestations of vitamin B12 deficiency [3,4].
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Contraindications: Do not administer to patients with known hypersensitivity to hydroxocobalamin, another vitamin B12 preparation, cobalt, benzyl alcohol, or any component of the formulation [1].
Hypersensitivity: Serious hypersensitivity reactions, including anaphylactic shock, have been reported after parenteral hydroxocobalamin and other vitamin B12 products. Discontinue administration immediately and initiate appropriate medical treatment if a serious reaction occurs [1].
Formulation-specific precautions: This formulation contains 0.9% benzyl alcohol. Benzyl alcohol has been associated with serious adverse reactions in neonates and premature infants. The Xseer product label specifies intramuscular administration and states that the product is not for intravenous administration [1].
Clinical monitoring: Intensive correction of severe megaloblastic anemia may produce hypokalemia as erythropoiesis increases. Consider appropriate clinical and laboratory monitoring during the initial treatment period in patients with severe deficiency [1,3].
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Long-term use of metformin, proton pump inhibitors, and histamine-2 receptor antagonists can reduce gastrointestinal vitamin B12 absorption and contribute to deficiency. These effects do not directly prevent absorption of intramuscularly administered hydroxocobalamin [2,3].
Formal interaction studies have not been conducted for this compounded parenteral formulation. Concurrent medications and injectable products should be reviewed according to the patient’s clinical condition and the applicable administration protocol.
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Reported or clinically relevant reactions may include:
Hypersensitivity: Rash, pruritus, urticaria, flushing, edema, dyspnea, hypotension, or anaphylaxis
Injection site: Pain, tenderness, erythema, swelling, or local irritation
Gastrointestinal: Nausea or diarrhea
Neurologic: Headache or dizziness
General: Fever, chills, flushing, or malaise
Metabolic: Hypokalemia during intensive treatment of severe megaloblastic anemia
Respiratory difficulty, facial or airway swelling, hypotension, or other evidence of a serious reaction requires immediate discontinuation and medical evaluation [1].
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Pregnancy: Vitamin B12 requirements increase during pregnancy. Administer when clinically indicated and under the direction of a qualified healthcare professional [2,3].
Lactation: Vitamin B12 is present in human milk. Administration should be based on maternal clinical need and the importance of adequate vitamin B12 status for the breastfed infant [2,3].
Pediatric use: Carefully calculate the prescribed dose and administration volume. Consider cumulative benzyl alcohol exposure, particularly in neonates and premature infants [1].
Older adults: Evaluate medication-associated malabsorption, autoimmune gastritis, prior gastrointestinal surgery, dietary factors, neurologic status, and the anticipated need for maintenance therapy [2,3].
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Store at USP Controlled Room Temperature, 20°C to 25°C (68°F to 77°F). Excursions are permitted between 15°C and 30°C (59°F to 86°F) [1].
Protect from light and freezing. Keep the vial in its carton until use.
Inspect the solution and container before each use. Do not use if the solution is cloudy, unexpectedly discolored, or contains visible particulate matter.
Use strict aseptic technique during vial entry and product withdrawal. Follow the product-specific label and applicable facility procedures for handling after initial puncture, beyond-use dating, and disposal.
Keep out of the reach of children.
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[1] DailyMed. Hydroxocobalamin Injection, 1 mg/mL [Xseer Pharmaceuticals product label]. NDC 85551-125-30.
[2] National Institutes of Health, Office of Dietary Supplements. Vitamin B12: Fact Sheet for Health Professionals. Updated July 2, 2025.
[3] Green R, Allen LH, Bjørke-Monsen AL, et al. Vitamin B12 deficiency. Nat Rev Dis Primers. 2017;3:17040. doi:10.1038/nrdp.2017.40.
[4] Mascarenhas R, Gouda H, Ruetz M, Banerjee R. Human B12-dependent enzymes: methionine synthase and methylmalonyl-CoA mutase. Methods Enzymol. 2022;668:309–343. PMID:35589199.
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This information is intended for licensed healthcare professionals and is provided for product-information purposes only. Refer to the product-specific label, lot-specific Certificate of Analysis, applicable institutional protocols, and independent clinical judgment before ordering, preparing, or administering this compounded drug product.
