Important: This page is general information, not medical advice. It does not recommend or prescribe any treatment. Always consult your doctor or pharmacist before starting, stopping or changing any medicine.
Quick facts
- Drug class
- Vitamin B12 [EPC]
- How it is given
- intramuscular, subcutaneous
- Type
- human prescription drug
- RxNorm ID
- 309594
We do not publish dosing. How much of this medicine to take, how often, and for how long depends on your age, weight, kidney and liver function, other conditions and other medicines. That is a decision for the person who prescribes or dispenses it. Follow the directions on your own pack and ask your pharmacist if anything is unclear.
What it is used to treat
INDICATIONS AND USAGE 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. Requirements of vitamin B 12 in excess of normal (due to pregnancy, thyrotoxicosis, hemolytic anemia, hemorrhage, malignancy, hepatic and renal disease) can usually be met with oral supplementation. Cyanocobalamin Injection is also suitable for the vitamin B 12 absorption test ( Schilling Test ).
About this medicine
DESCRIPTION Cyanocobalamin Injection, USP is a sterile solution of cyanocobalamin for intramuscular or subcutaneous injection. Each mL contains 1,000 mcg cyanocobalamin. Each vial also contains Sodium Chloride, 0.9%. Benzyl Alcohol, 1.5%, is present as a preservative. Hydrochloric acid and/or sodium hydroxide may have been added during manufacture to adjust the pH (range 4.5 to 7.0). Cyanocobalamin appears as dark red crystals or as an amorphous or crystalline red powder. It is very hygroscopic in the anhydrous form, and sparingly soluble in water (1:80). It is stable to autoclaving for short periods at 121°C. The vitamin B 12 coenzymes are very unstable in light. The chemical name is 5,6-dimethyl-benzimidazolyl cyanocobamide; the molecular formula is C 63 H 88 CoN 14 O 14 P. The cobalt content is 4.34%. The molecular weight is 1355.39. The structural formula is represented below. Structural Formula
Who should not take it
CONTRAINDICATIONS Sensitivity to cobalt and/or vitamin B 12 is a contraindication.
Warnings
WARNINGS 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.
Reported side effects
ADVERSE REACTIONS 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 .
If too much is taken
OVERDOSAGE No overdosage has been reported with this drug.
Before you take anything new
Tell your pharmacist or doctor about every medicine you take — including ones bought without a prescription, herbal products and supplements. Interactions are one of the most common avoidable causes of harm from medicines, and a pharmacist can check your full list in a couple of minutes.
This page is built from the openFDA record of the U.S. Food and Drug Administration's approved labelling for this product, effective 12 June 2025. Label text has been shortened and reformatted for readability; safety wording has not been altered in meaning. FDA labelling describes products approved in the United States — brand names, strengths, formulations and approved uses may differ in your country. Always read the leaflet that comes with your own pack. PocketsInfo is not affiliated with, and is not endorsed by, the FDA. Retrieved 2026-07-30.