Vitamin B12

Mechanism-of-action class: Enzyme Interactions.

• Cyanocobalamin is indicated for vitamin B 12 deficiencies due to malabsorption which may be associated with the following conditions: Addisonian (pernicious) anemia Gastrointestinal pathology, dysfunction, or surgery, including gluten enteropathy or sprue, small bowel bacteria overgrowth, total or partial gastrectomy Fish tapeworm infestation Malignancy of pancreas or bowel Folic acid deficiency It may be possible to treat the underlying disease by surgical correction of anatomic lesions leading to small bowel bacterial overgrowth, expulsion of fish tapeworm, discontinuation of drugs leading to vitamin malabsorption (see Drug/Laboratory Test Interactions ), use of a gluten-free diet in nontropical sprue, or administration of antibiotics in tropical sprue. Such measures remove the need for long-term administration of cyanocobalamin.ICD-10: D64.9

• Sensitivity to cobalt and/or vitamin B 12 is a contraindication.contraindicated

Avoid using the intravenous route. Use of this product intravenously will result in almost all of the vitamin being lost in the urine. Pernicious Anemia Parenteral vitamin B 12 is the recommended treatment and will be required for the remainder of the patient's life. The oral form is not dependable. A dose of 100 mcg daily for 6 or 7 days should be administered by intramuscular or deep subcutaneous injection. If there is clinical improvement and if a reticulocyte response is observed, the same amount may be given on alternate days for seven doses, then every 3 to 4 days for another 2 to 3 weeks. By this time hematologic values should have become normal. This regimen should be followed by 100 mcg monthly for life. Folic acid should be administered concomitantly if needed. Patients with Normal Intestinal Absorption Where the oral route is not deemed adequate, initial treatment similar to that for patients with pernicious anemia may be indicated depending on the severity of the deficiency. Chronic treatment should be with an oral B 12 preparation. If other vitamin deficiencies are present, they should be treated. Schilling Test The flushing dose is 1,000 mcg. Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit.

Patients with early Leber's disease (hereditary optic nerve atrophy) who were treated with cyanocobalamin suffered severe and swift optic atrophy. Hypokalemia and sudden death may occur in severe megaloblastic anemia which is treated intensely. Anaphylactic shock and death have been reported after parenteral vitamin B 12 administration. An intradermal test dose is recommended before cyanocobalamin injection is administered to patients suspected of being sensitive to this drug. This product contains benzyl alcohol. Benzyl alcohol has been reported to be associated with a fatal "Gasping Syndrome" in premature infants. This product contains aluminum that may be toxic. Aluminum may reach toxic levels with prolonged parenteral administration if kidney function is impaired. Premature neonates are particularly at risk because their kidneys are immature, and they require large amounts of calcium and phosphate solutions, which contain aluminum. Research indicates that patients with impaired kidney function, including premature neonates, who receive parenteral levels of aluminum at greater than 4 to 5 mcg/kg/day accumulate aluminum at levels associated with central nervous system and bone toxicity. Tissue loading may occur at even lower rates of administration.

Generalized: Anaphylactic shock and death have been reported with administration of parenteral vitamin B 12 (see WARNINGS ). Cardiovascular: Pulmonary edema and congestive heart failure early in treatment; peripheral vascular thrombosis Hematological: Polycythemia vera Gastrointestinal: Mild transient diarrhea Dermatological: Itching; transitory exanthema Miscellaneous: Feeling of swelling of entire body To report SUSPECTED ADVERSE REACTIONS, contact Meitheal Pharmaceuticals Inc. at 1-844-824-8426 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch .

Pregnancy Teratogenic Effects Adequate and well-controlled studies have not been done in pregnant women. However, vitamin B 12 is an essential vitamin and requirements are increased during pregnancy. Amounts of vitamin B 12 that are recommended by the Food and Nutrition Board, National Academy of Science-National Research Council for pregnant women (4 mcg daily) should be consumed during pregnancy.

No overdosage has been reported with this drug.

• Oct 20, 1971ANDAANDA080515West-ward Pharms Int
• Apr 26, 1972ANDAANDA080737Am Regent
• Jun 20, 1973ANDAANDA080557Fresenius Kabi Usa
• Feb 21, 2001NDANDA021265Sandoz Canada Inc
• Jan 31, 2005NDANDA021642Endo Operations
• Dec 11, 2015ANDAANDA206503Somerset Theraps Llc
• Dec 18, 2018ANDAANDA209255Vitruvias Therap
• Dec 18, 2018ANDAANDA209429Somerset Theraps Llc

Recent PubMed references pinned to Vitamin B12 as a MeSH major topic. Citations link to pubmed.ncbi.nlm.nih.gov.

• Associations between vitamin B6 and vitamin B12 intake and lung function: A cross-sectional study based on NHANES 2007 to 2012.
  Medicine · 2026 · Wang W, Gu Y
  PMID 42260844DOI 10.1097/MD.0000000000049118
• Enrichment of Platelet-Rich Fibrin Using Cobalamin and Alpha-Tocopherol to Modulate Growth Factor Release.
  Journal of visualized experiments : JoVE · 2026 · Ozcan M, Saygı H, Alkaya B, et al.
  PMID 42258410DOI 10.3791/71016
• Association between proton pump inhibitor use and vitamin B12 deficiency: a retrospective cohort study in primary care centers in Riyadh, Saudi Arabia.
  Annals of Saudi medicine · 2026 · Alanazi S, Bin Sulaiman N, Aldahoul SK, et al.
  PMID 42251516DOI 10.5144/0256-4947.2026.159
• Effect of NSAIDs, melatonin, vitamin D and vitamin B12 chronotherapy on postoperative recovery after third molar surgical extraction: A pilot randomized crossover placebo-controlled trial.
  Oral and maxillofacial surgery · 2026 · Abusamak M, Pérez-González F, Ruiz LV, et al.
  PMID 42230417DOI 10.1007/s10006-026-01582-0
• Vitamin B12 supplementation for growth, development, and cognition in children.
  The Cochrane database of systematic reviews · 2026 · Larvie DY, Güitrón Leal CE, Venkatramanan S, et al.
  PMID 42227307DOI 10.1002/14651858.CD015264.pub2
• Vitamin B(12) Supplementation: Is More Always Better?
  Nutrients · 2026 · Yepes-Calderón M, Doorenbos CSE, Stegmann ME, et al.
  PMID 42197057DOI 10.3390/nu18101597
• Red Blood Cell Parameters, Iron Metabolism and Vitamin B12 Status in Children with Obesity: Associations with Diet and Obesity-Related Complications.
  Nutrients · 2026 · Cichocka-Mroczek E, Iwańska A, Goncerz D, et al.
  PMID 42197025DOI 10.3390/nu18101566
• Associations Between Concentrations of Vitamin D3, Vitamin B12, and Folate and the Well-Being of Medical Students.
  Nutrients · 2026 · Cieślikiewicz B, Bieńkowska A, Maksymowicz S, et al.
  PMID 42197019DOI 10.3390/nu18101559

The 10 most recently updated of 705 ClinicalTrials.gov registrations naming Vitamin B12 as an intervention. Registration is not evidence of efficacy or safety — reference crosswalk only.

• Host-Diet-Gut Interaction Post Vegan Diet in Pediatric Autoimmune Hepatitis.
  Recruiting · Interventional · 40 enrolled · Institute of Liver and Biliary Sciences, India
  NCT07118657updated 2026-06-12
• Clinical and Laboratory Study of Methylmalonic Acidemia
  Recruiting · Observational · 2,275 enrolled · National Human Genome Research Institute (NHGRI)
  NCT00078078updated 2026-06-11
• Biological Optimization Versus Standard Care in Post-POEM Achalasia Patients (BIO-POEM)
  Active not recruiting · Interventional · 166 enrolled · Asian Institute of Gastroenterology, India
  NCT07620899updated 2026-06-02
• Immune-Mitochondrial Correction in Military Recruits
  Not yet recruiting · Interventional · 200 enrolled · MIPO Clinic
  NCT07622147updated 2026-06-02
• Anemia Therapy in Patients With Infective Endocarditis
  Recruiting · Phase 4 · Interventional · 74 enrolled · Rigshospitalet, Denmark
  NCT07523646updated 2026-05-29
• A Trial of Vitamin B12 in Septic Shock
  Completed · Phase 2 · Interventional · 20 enrolled · Medical College of Wisconsin
  NCT03783091updated 2026-05-27
• Vitamin B Complex for Inferior Alveolar Nerve Paresthesia Recovery
  Not yet recruiting · Phase 4 · Interventional · 50 enrolled · University of Sao Paulo
  NCT07592897updated 2026-05-20
• Impact of a Novel Functional Snack on Perimenopausal Symptoms and Well-being
  Recruiting · Interventional · 20 enrolled · King's College London
  NCT07599930updated 2026-05-20
• Effect of a Food Intervention With a Prebiotic Alone or Combined With B-vitamins on Gut Microbiota Diversity, Inflammation and Mental Health Outcomes in Older Adults (GutFood)
  Recruiting · Interventional · 84 enrolled · University of Ulster
  NCT07592975updated 2026-05-18
• Testing the Use of Combination Immunotherapy Treatment (N-803 [ALT-803] Plus Pembrolizumab) Against the Usual Treatment for Advanced Non-small Cell Lung Cancer (A Lung-MAP Treatment Trial)
  Active not recruiting · Phase 2 · Phase 3 · Interventional · 82 enrolled · SWOG Cancer Research Network
  NCT05096663updated 2026-05-18

Frequently asked questions

How does Vitamin B12 work?

Mechanism-of-action class: Enzyme Interactions.

What is Vitamin B12 used for?

According to FDA labeling, Vitamin B12 carries indications including: Cyanocobalamin is indicated for vitamin B 12 deficiencies due to malabsorption which may be associated with the following conditions: Addisonian (pernicious) anemia Gastrointestinal pathology, dysfunction, or surgery, including gluten enteropathy or sprue, small bowel bacteria overgrowth, total or partial gastrectomy Fish tapeworm infestation Malignancy of pancreas or bowel Folic acid deficiency It may be possible to treat the underlying disease by surgical correction of anatomic lesions leading to small bowel bacterial overgrowth, expulsion of fish tapeworm, discontinuation of drugs leading to vitamin malabsorption (see Drug/Laboratory Test Interactions ), use of a gluten-free diet in nontropical sprue, or administration of antibiotics in tropical sprue. Such measures remove the need for long-term administration of cyanocobalamin.. This is a reference summary of labeled uses, not medical advice or a treatment recommendation.

What class of drug is Vitamin B12?

Vitamin B12 is classified as Vitamin B12 (cyanocobalamin and analogues), Vitamin B12, Enzyme Interactions, Cellular Activity Alteration.

What are the brand names for Vitamin B12?

Vitamin B12 is marketed under brand names including Animi-3 with Vitamin D, Concept OB, Dodex, Eldertonic, Ellis Tonic, Ferocon, Ferralet 90, Ferraplus.

What are the contraindications for Vitamin B12?

Vitamin B12 labeling lists contraindications including: Sensitivity to cobalt and/or vitamin B 12 is a contraindication.. Always consult the full prescribing information and a clinician.