Vitamin B12
Vitamin B12 is an essential water-soluble vitamin and hematinic agent used to treat and prevent B12 deficiency, which can cause megaloblastic anemia and neurological complications. It is commonly prescribed for patients with pernicious anemia, malabsorption disorders, or dietary deficiencies such as in vegans and vegetarians, and for those with increased requirements like pregnant women or the elderly.
Vitamin B12 treats B12 deficiency and related anemias by supporting red blood cell production and nerve function.
Key facts at a glance
- ATC
- B03BA01
- RxNorm
- 11248
- Generic
- Vitamin B12
- Class
- atc-b03
- Brands
- Ferocon, Ferraplus, Ferrex 150 Forte Plus, Folbecal, Folgard OS, Hemocyte Plus, Hemax, Icar-C Plus, Multi-Delyn, Folgard, Irospan Tablet, Lactocal, Vitafol-One, MTX Support, Animi-3 with Vitamin D
- Availability
- rx
- Lactation
- unknown
- Routes
- oral, sublingual, nasal
- Forms
- tablet, solution, capsule, gel, spray
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Dosage and administration
- Usual dose
- 500mg twice daily
- Maximum
- consult physician
- Frequency
- every 12 hours
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 250mg twice daily
- Maximum
- consult physician
- Frequency
- every 12 hours
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 400mg daily
- Maximum
- consult physician
- Frequency
- once daily
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
Overdose information
Special Populations
10 groupspregnancy
first trimesterno adjustment needed
continue supplementation as recommended by healthcare provider; essential for proper fetal neural tube development
routine prenatal care
pregnancy
second trimesterno adjustment needed
continue supplementation; important for maternal and fetal blood health
routine prenatal care
pregnancy
third trimesterno adjustment needed
continue supplementation; important for final trimester development
routine prenatal care
lactation
breastfeedingno adjustment needed
continue supplementation; important for breast milk quality
routine postpartum care
geriatric
elderlyoften requires higher doses due to reduced absorption
supplementation often necessary due to age-related decreased intrinsic factor and gastric acid secretion
periodic B12 level monitoring recommended
pediatric_age
infants and childrendose based on age and weight; pediatric formulations available
follow pediatric dosage guidelines; important for growth and neurological development
routine pediatric checkups
renal_impairment
mild to moderateno dose adjustment typically required
can be used safely; renal excretion minimal
standard monitoring
renal_impairment
severemonitor and adjust as needed
use under medical supervision; may require parenteral administration in dialysis patients
regular B12 level monitoring
Use with caution and monitor for adverse effects.
hepatic_impairment
mild to moderateno dose adjustment typically required
can be used safely; not primarily metabolized by liver
standard monitoring
alcohol_users
chronic alcohol usemay require higher doses due to impaired absorption and increased excretion
supplementation often recommended; alcohol interferes with B12 absorption and storage
periodic B12 level monitoring recommended
Use with caution and monitor for adverse effects.
Statistics and clinical data
Commonly prescribed since
General prescribing information
Drug class
Drug class information
Common uses
Common therapeutic uses
Typical adult dose
Standard dosing information
Treatment and prevention of vitamin B12 deficiency states including pernicious anemia, megaloblastic anemia, and neurological manifestations of B12 deficiency. Also used for B12 supplementation in at-risk populations such as vegans, vegetarians, elderly patients, and those with malabsorption syndromes or gastrointestinal disorders.
Vitamin B12 acts as an essential cofactor for methionine synthase and methylmalonyl-CoA mutase enzymes, supporting DNA synthesis, normal red blood cell formation (erythropoiesis), and maintenance of the myelin sheath covering nerves. This corrects the impaired cell division and hematopoiesis seen in B12 deficiency.
Available in oral, intramuscular, and subcutaneous formulations. Cyanocobalamin and hydroxocobalamin are common synthetic forms. B12 is generally well-tolerated with minimal toxicity since excess is excreted in urine. Monitor potassium levels during initial treatment as hypokalemia may occur. Oral absorption requires intrinsic factor; consider alternative routes in malabsorption.
Contraindications
Conditions and patient states where this medication should be avoided or used with caution.
Do not use (1)
Known allergy to this medication or its components
Use caution (1)
Consult healthcare provider for benefits vs risks assessment
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 20, 2026. · Read our editorial policy