Dosing & Uses
Dosage Forms & Strengths
tablet
- 100mcg
- 250mcg
- 500mcg
- 1000mcg
tablet, extended release
- 1000mcg
tablet, sublingual
- 2500mcg
injectable solution
- 1000mcg/mL
nasal spray
- 500mcg/spray
Nutritional Supplementation
Recommended daily allowance (RDA)
>19 years: 2.4 mcg
Pregnant women: 2.6 mcg
Breastfeeding women: 2.8 mcg
Dietary supplement: 50-6,000 mcg/day
Pernicious Anemia
Manufacturer recommendation: 100 mcg IM/SC once daily for 6-7 days, then every other day for 7 doses, then every 3-4 days for 2-3 weeks, then monthly
Alternative parenteral dosing: 1000 mcg IM/SC once daily for 7 days, then weekly for 1 month, then monthly
Nasal spray: 500 mcg (1 spray in 1 nostril) weekly; if patient is taking hot meals, spray should be administered 1 hour before or after meal
B12 Deficiency
Initial: 30 mcg IM once daily for 5-10 days
Maintenance: 100-200 mcg IM monthly
Nasal dose: 500 mcg once weekly
Dosing considerations
- PO absorption requires intrinsic factor
- Cyanide poisoning: See Hydroxycobalamin AD
Dosage Forms & Strengths
tablet
- 100mcg
- 250mcg
- 500mcg
- 1000mcg
tablet, extended release
- 1000mcg
tablet, sublingual
- 2500mcg
injectable solution
- 1000mcg/mL
nasal spray
- 500mcg/spray
Nutritional Supplementation
RDA
0-6 months: 0.4 mcg
7-12 months: 0.5 mcg
1-3 years: 0.9 mcg
4-8 years: 1.2 mcg
9-13 years: 1.8 mcg
>14 years: 2.4 mcg
Pernicious Anemia
30-50 mcg IM/SC once daily for &ge2 weeks for total dose of 1,000 mcg to 5,000 mcg administer concomitantly with 1 mg/day of folic acid for 1 month
Maintenance: 100 mcg IM/SC monthly
B12 Deficiency
0.2 mcg/kg for 2 days; follow by 1,000 mcg/day for 2-7 days; follow by 100 mcg/day for 2-7 days; then 100 mcg/week for 1 month
Maintenance: 100 mcg IM/SC monthly
Interactions
Interaction Checker
No Results
Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor
Adverse Effects
>10%
Arthralgia (12%)
Dizziness (12%)
Headache (12%)
Nasopharyngitis (12%)
Frequency Not Defined
Anaphylaxis
Angioedema
Congestive heart failure
Peripheral vascular disease
Pulmonary edema
Diarrhea
Dyspepsia
Polycythemia vera
Sore throat
Nervousness
Rhinitis
Glossitis
Hypoesthesia
Warnings
Contraindications
Hypersensitivity to product; sensitivity to cobalt
Cautions
Intensive treatment of B12-deficient megaloblastic anemia may cause hypokalemia and sudden death
Nasal disease; defer use until symptoms resolve
Use with caution in patients with Leber optic nerve atrophy
Injection is incompatible with some common drugs (eg, warfarin and several phenothiazines) but is compatible with vitamins B and C
Vitamin B12 deficiency for >3 months results in irreversible degenerative CNS lesions
Thrombocytosis may occur with treatment of severe vitamin B12 megaloblastic anemia
Oral and intranasal route are not indicated for the treatment of pernicious anemia until symptoms resolve
Vitamin B12 deficiency masks signs of polycythemia vera; vitamin B12 administration may unmask condition
IM and SC route used to treat pernicious anemia; oral and intranasal not indicated until hematologic remission and no signs of nervous system involvement
Use with caution in patients with Leber’s disease; B12 treatment may result in rapid optic atrophy
Parenteral product may contain aluminum; toxic aluminum concentrations may occur with renal dysfunction, high doses, or prolonged use
Efficacy of intranasal administration in patients with nasal pathology or concomitant therapy has not been determined; use with caution
Pregnancy & Lactation
Pregnancy category: A; C (for doses exceeding RDA and for intranasal products)
Lactation: Drug distributed in milk; safe to use
Pregnancy Categories
A:Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B:May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C:Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D:Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X:Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA:Information not available.
Pharmacology
Mechanism of Action
Coenzyme; metabolic functions include protein synthesis and carbohydrate metabolism
Plays role in cell replication and hematopoiesis
Absorption
Bioavailability: 6.1% (intranasal solution relative to IM)
Distribution
Distributed to liver, bone marrow, and other tissues
Protein bound: Binding to transcobalamins
Elimination
Excretion: Urine (excess amount), bile (mostly reabsorbed)
Images
Patient Handout
Formulary
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