BERUBIGEN

Clinical safety rating: caution

Comprehensive clinical and safety monograph for BERUBIGEN (BERUBIGEN).

How it works

BERUBIGEN (cyanocobalamin) is a form of vitamin B12 that acts as a coenzyme for methylmalonyl-CoA mutase and methionine synthase, essential for DNA synthesis, fatty acid metabolism, and myelin production. It promotes red blood cell maturation and neurologic function.

What the body does with it

Metabolism	Cyanocobalamin is converted to active coenzymes (methylcobalamin and adenosylcobalamin) in tissues. Metabolism involves hepatic conversion and enterohepatic recirculation. The cyano group is converted to cyanide (minimal) and excreted renally.
Excretion	Primarily renal (50-90% of absorbed dose as unchanged drug via glomerular filtration); minor biliary/fecal (<10%) and negligible pulmonary elimination.
Half-life	Terminal elimination half-life: ~6-7 days (range 5-10 days). Clinically signifies slow clearance; repeated dosing leads to accumulation in liver stores.
Protein binding	~90% bound to transcobalamin II and to a lesser extent haptocorrin (R-binders).
Volume of Distribution	0.3-0.5 L/kg in healthy adults; expands in B12-deficient states due to increased tissue binding. Clinical meaning: distributes primarily into liver (>50% of total body stores) and bone marrow.
Bioavailability	Oral: <1% (requires intrinsic factor for absorption; 1-3% at high doses via passive diffusion). Intramuscular/Subcutaneous: >95% bioavailability.
Onset of Action	Oral: ~4-6 hours (first signs of reticulocyte response). Intramuscular: 24-72 hours (hematologic response).
Duration of Action	Single dose supports erythropoiesis for 2-4 weeks. Following administration, maintenance therapy typically required every 1-3 months for pernicious anemia.

Classification & Brands

Dosing & administration

1000 mcg intramuscularly or deep subcutaneous once daily for 1 week, then 1000 mcg weekly for 1 month, then 1000 mcg monthly for life.

Dosage form	INJECTABLE
Renal impairment	No dose adjustment required for any degree of renal impairment.
Liver impairment	No dose adjustment required for Child-Pugh A or B; no data for Child-Pugh C.
Pediatric use	Initial: 1000 mcg intramuscularly or deep subcutaneous daily for 1 week; maintenance: 1000 mcg every 2-4 weeks. For infants <6 months: 0.1-0.4 mcg/kg daily orally if oral route used.
Geriatric use	Same as adult dosing; monitor for hypokalemia and cyanocobalamin hypersensitivity.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for BERUBIGEN (BERUBIGEN).

Breastfeeding	Cyanocobalamin (vitamin B12) is naturally present in breast milk. Exogenous supplementation has not been well studied; however, it is generally considered compatible with breastfeeding due to endogenous presence. No specific M/P ratio reported.
Teratogenic Risk	Pregnancy category C. No adequate studies in pregnant women; animal reproduction studies have not been conducted. Use only if clearly needed and potential benefit justifies risk. Trimester-specific risks are not established.
Fetal Monitoring

Warnings & precautions

■ FDA Black Box Warning

None.

Side Effect Profile

Serious Effects

Absolute Contraindications

Hypersensitivity to cyanocobalamin or cobalt; Leber's disease (hereditary optic nerve atrophy); methylmalonic acidemia with methylmalonyl-CoA mutase deficiency (relative).

Clinical Precautions

Precautions	Hypokalemia and thrombocytosis may occur during initial treatment of pernicious anemia. Use caution in patients with Leber's disease (optic nerve atrophy). Avoid use in patients with cobalt allergy. Monitor serum potassium and platelet count.
Food/Dietary	Alcohol consumption may interfere with B12 absorption and should be limited. Dietary intake of B12-rich foods (meat, fish, eggs, dairy) does not replace therapeutic doses but supports overall status.

Clinical Tips & Counseling

Drug interactions

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BERUBIGEN

Clinical safety rating: caution

Comprehensive clinical and safety monograph for BERUBIGEN (BERUBIGEN).

How it works

What the body does with it

Metabolism	Cyanocobalamin is converted to active coenzymes (methylcobalamin and adenosylcobalamin) in tissues. Metabolism involves hepatic conversion and enterohepatic recirculation. The cyano group is converted to cyanide (minimal) and excreted renally.
Excretion	Primarily renal (50-90% of absorbed dose as unchanged drug via glomerular filtration); minor biliary/fecal (<10%) and negligible pulmonary elimination.
Half-life	Terminal elimination half-life: ~6-7 days (range 5-10 days). Clinically signifies slow clearance; repeated dosing leads to accumulation in liver stores.
Protein binding	~90% bound to transcobalamin II and to a lesser extent haptocorrin (R-binders).
Volume of Distribution	0.3-0.5 L/kg in healthy adults; expands in B12-deficient states due to increased tissue binding. Clinical meaning: distributes primarily into liver (>50% of total body stores) and bone marrow.
Bioavailability	Oral: <1% (requires intrinsic factor for absorption; 1-3% at high doses via passive diffusion). Intramuscular/Subcutaneous: >95% bioavailability.
Onset of Action	Oral: ~4-6 hours (first signs of reticulocyte response). Intramuscular: 24-72 hours (hematologic response).
Duration of Action	Single dose supports erythropoiesis for 2-4 weeks. Following administration, maintenance therapy typically required every 1-3 months for pernicious anemia.

Classification & Brands

Dosing & administration

1000 mcg intramuscularly or deep subcutaneous once daily for 1 week, then 1000 mcg weekly for 1 month, then 1000 mcg monthly for life.

Dosage form	INJECTABLE
Renal impairment	No dose adjustment required for any degree of renal impairment.
Liver impairment	No dose adjustment required for Child-Pugh A or B; no data for Child-Pugh C.
Pediatric use	Initial: 1000 mcg intramuscularly or deep subcutaneous daily for 1 week; maintenance: 1000 mcg every 2-4 weeks. For infants <6 months: 0.1-0.4 mcg/kg daily orally if oral route used.
Geriatric use	Same as adult dosing; monitor for hypokalemia and cyanocobalamin hypersensitivity.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for BERUBIGEN (BERUBIGEN).

Breastfeeding	Cyanocobalamin (vitamin B12) is naturally present in breast milk. Exogenous supplementation has not been well studied; however, it is generally considered compatible with breastfeeding due to endogenous presence. No specific M/P ratio reported.
Teratogenic Risk	Pregnancy category C. No adequate studies in pregnant women; animal reproduction studies have not been conducted. Use only if clearly needed and potential benefit justifies risk. Trimester-specific risks are not established.
Fetal Monitoring

Warnings & precautions

■ FDA Black Box Warning

None.

Side Effect Profile

Serious Effects

Absolute Contraindications

Hypersensitivity to cyanocobalamin or cobalt; Leber's disease (hereditary optic nerve atrophy); methylmalonic acidemia with methylmalonyl-CoA mutase deficiency (relative).

Clinical Precautions

Precautions	Hypokalemia and thrombocytosis may occur during initial treatment of pernicious anemia. Use caution in patients with Leber's disease (optic nerve atrophy). Avoid use in patients with cobalt allergy. Monitor serum potassium and platelet count.
Food/Dietary	Alcohol consumption may interfere with B12 absorption and should be limited. Dietary intake of B12-rich foods (meat, fish, eggs, dairy) does not replace therapeutic doses but supports overall status.

Clinical Tips & Counseling

Drug interactions

Loading safety data…