Vitamin B12

Class: Vitamin B Complex
VA Class: VT100
Chemical Name: 5,6-dimethyl-benzimidazolyl cyanocobamide,
CAS Number: 68-19-9
Brands: Nascobal

Introduction

A cobalt-containing, B complex vitamin. Cyanocobalamin and hydroxocobalamin are synthetic forms of vitamin B₁₂.

Hydroxocobalamin: Antidote for cyanide poisoning.

Uses for Vitamin B12

Vitamin B12 Deficiency

Treatment of pernicious anemia and other vitamin B₁₂ deficiency states.

Parenteral cyanocobalamin or hydroxocobalamin: Treatment of vitamin B₁₂ deficiency due to inadequate intrinsic factor (IF) secretion; impaired intestinal absorption; or dietary deficiency associated with a vegetarian diet.

Cyanocobalamin is considered the parenteral vitamin B₁₂ preparation of choice; hydroxocobalamin may be preferred for initial treatment.

Cyanocobalamin nasal spray: Used to maintain hematologic status in adults with pernicious anemia with no nervous system involvement who have responded to parenteral vitamin B ₁₂ therapy. Also used as a supplement for vitamin B₁₂ deficiency due to dietary deficiency, impaired absorption, inadequate secretion of IF, or certain other conditions.

Dietary Requirements

Adequate intake needed to prevent vitamin B₁₂ deficiency and neurologic complications associated with vitamin B₁₂ deficiency.

Adequate intake of vitamin B₁₂ usually can be accomplished through consumption of foodstuffs; however, about 10–30% of geriatric individuals are unable to absorb naturally occurring vitamin B₁₂ and should consume vitamin B₁₂-fortified food or supplements. Inadequate intake can occur in vegetarians and their breast-fed infants. Mixed foods whose main ingredient is meat, fish, or poultry; milk; and fortified ready-to-eat cereals are the main sources of vitamin B₁₂ in the diet of US adults and children.

Recommended Dietary Allowance (RDA) in adults based on amount needed to maintain hematologic status and normal serum vitamin B₁₂ concentrations.

Adequate intake (AI) established for infants ≤6 months of age based on observed mean vitamin B₁₂ intake of infants fed principally human milk; AI for infants 7–12 months of age based on AI for younger infants and data in adults.

RDA for children 1–18 years of age based on data in adults.

Metabolic Disorders

Parenteral cyanocobalamin: Management of hereditary deficiency of transcobalamin II.

Schilling Test

Parenteral cyanocobalamin and hydroxocobalamin: Used in conjunction with cyanocobalamin Co 57 in Schilling test to study vitamin B₁₂ absorption.

Cyanide Poisoning

Hydroxocobalamin (Cyanokit): Treatment of known or suspected cyanide poisoning. Used in conjunction with airway and cardiovascular support and management of seizure activity.

Vitamin B12 Dosage and Administration

Administration

Cyanocobalamin is administered orally, intranasally, or by IM or deep sub-Q injection.

Hydroxocobalamin is administered by IM injection or IV infusion.

Oral Administration

Oral therapy is inferior to parenteral therapy. May be used for treatment of dietary vitamin B₁₂ deficiency in patients with normal GI absorption.

Parenteral Administration

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