Indications And Usage

Vitamin B12 is important for growth, cell reproduction, blood formation, and protein and tissue synthesis.

Vitamin B12 is used to treat vitamin B12 deficiency in people with pernicious anemia and other conditions

Administration

Pernicious Anemia:

Initial dose: 1000 mcg intramuscularly or deep subcutaneous once a day for 6 to 7 days

If clinical improvement and reticulocyte response is seen from the above dosing:

-100 mcg every other day for 7 doses, then;

-100 mcg every 3 to 4 days for 2 to 3 weeks, then;

Maintenance dose: 100 to 1000 mcg monthly

Nutritional Deficiency:

25 to 2000 mcg orally daily

Schilling Test:

1000 mcg intramuscularly is the flushing dose

Contraindications

Sensitivity to cobalt and/or Vitamin B12 is a contraindication.

Precautions

Vitamin B12 deficiency that is allowed to progress for longer than three months may produce permanent degenerative lesions of the spinal cord. Doses of folic acid greater than 0.1 mg/day may result in hematologic remission in patients with Vitamin B12 deficiency. Neurologic manifestations will not be prevented with folic acid, and if not treated with Vitamin B12, irreversible damage will result.

Doses of cyanocobalamin exceeding 10 mcg daily may produce hematologic response in patients with folate deficiency. In discriminate administration may mask the true diagnosis.

Adverse Reactions

Anaphylactic shock and death have been reported with administration of parenteral Vitamin B12.

Pregnancy and lactation

Pregnancy Category C

Vitamin B12 is known to be excreted in human milk. Amounts of Vitamin B12 that are recommended by the Food and Nutrition Board, National Academy of Science-National Research Council for lactating women (4 mcg daily) should be consumed during lactation.

Renal and liver Impairment

Cellular uptake of vitamin B12 in patients with chronic renal failure. This could cause a paradoxical increase in cellular homocysteine levels even with normal total B12 levels, resulting in a functional B12 deficiency.

Laboratory Tests