Get your patient on Cyanocobalamin - Cyanocobalamin injection, Solution (Cyanocobalamin)

Cyanocobalamin Injection 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 Injection.

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).

Avoid using the intravenous route. Use of this product intravenously will result in almost all of the vitamin being lost in the urine.

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

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 Sagent Pharmaceuticals, Inc. at 1-866-625-1618 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch .

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.

Vitamin B ₁₂ is essential to growth, cell reproduction, hematopoiesis, and nucleoprotein and myelin synthesis.

Cyanocobalamin is quantitatively and rapidly absorbed from intramuscular and subcutaneous sites of injection; the plasma level of the compound reaches its peak within 1 hour after intramuscular injection. Absorbed vitamin B ₁₂ is transported via specific B ₁₂ binding proteins, transcobalamin I and II to the various tissues. The liver is the main organ for vitamin B ₁₂ storage.

Within 48 hours after injection of 100 or 1,000 mcg of vitamin B ₁₂ , 50 to 98% of the injected dose may appear in the urine. The major portion is excreted within the first eight hours. Intravenous administration results in even more rapid excretion with little opportunity for liver storage.

Gastrointestinal absorption of vitamin B ₁₂ depends on the presence of sufficient intrinsic factor and calcium ions. Intrinsic factor deficiency causes pernicious anemia, which may be associated with subacute combined degeneration of the spinal cord. Prompt parenteral administration of vitamin B ₁₂ prevents progression of neurologic damage.

The average diet supplies about 5 to 15 mcg/day of vitamin B ₁₂ in a protein-bound form that is available for absorption after normal digestion. Vitamin B ₁₂ is not present in foods of plant origin, but is abundant in foods of animal origin. In people with normal absorption, deficiencies have been reported only in strict vegetarians who consume no products of animal origin (including no milk products or eggs).

Vitamin B ₁₂ is bound to intrinsic factor during transit through the stomach; separation occurs in the terminal ileum in the presence of calcium, and vitamin B ₁₂ enters the mucosal cell for absorption. It is then transported by the transcobalamin binding proteins. A small amount (approximately 1% of the total amount ingested) is absorbed by simple diffusion, but this mechanism is adequate only with very large doses. Oral absorption is considered too undependable to rely on in patients with pernicious anemia or other conditions resulting in malabsorption of vitamin B ₁₂ .

Cyanocobalamin is the most widely used form of vitamin B ₁₂ , and has hematopoietic activity apparently identical to that of the antianemia factor in purified liver extract. Hydroxycobalamin is equally as effective as cyanocobalamin, and they share the cobalamin molecular structure.

Cyanocobalamin Injection, USP is supplied as follows: