Hydroxocobalamin: Uses, Mechanism of Actions, and Deficiency Symptoms

What is Hydroxocobalamin or Vitamin B12?

Vitamin B12 also known as hydroxocobalamin or cyanocobalamin, is essential for purine nucleotide synthesis, certain amino acid metabolism, and proper cell development and reproduction. Hydroxocobalamin is a kind of vitamin B12 that is used to prevent and cure vitamin B12 insufficiency. Since this interacts with cyanide to create cyanocobalamin, it’s also utilized to treat diseases linked to cyanide poisoning. Reticulocytes grow after 2-5 days after parenteral treatment, followed by increases in haemoglobin, hematocrit, and erythrocyte count. Routes of administration of Hydroxocobalamin include Oral, IM (intramuscular), and IV (intravenous).

What is Hydroxocobalamin Used for?

Vitamin B12 hydroxocobalamin is a synthetic form of vitamin. Hydroxocobalamin is used to treat and prevent anaemia caused by a lack of vitamin B12 (when you have low levels of vitamin B12 in the body). Pernicious anaemia is the most common cause of vitamin B12 insufficiency in the United Kingdom.

Hydroxocobalamin Pharmacokinetics

For oral absorption, hydroxocobalamin, as a type of vitamin B12, requires the presence of stomach intrinsic factors. Small amounts are, however, absorbed by simple diffusion. The active ingredient, vitamin B12 binds to transcobalamin II in the plasma and is delivered to tissues as a complex. Approximately, 90% of the vitamin’s bodily stores are found in the liver, where it is kept as an active coenzyme. Hydroxocobalamin is eliminated in the bile after significant enterohepatic recirculation. Only a small portion of a given dose is eliminated unaltered in the urine.

Hydroxocobalamin Mechanism of Action

Hydroxocobalamin is a precursor to the active forms of vitamin B12, methylcobalamin, and adenosylcobalamin. Cofactors methylcobalamin and adenosylcobalamin are involved in DNA and amino acid synthesis, fatty acid metabolism, and nerve function maintenance. The methylcobalamin element of hydroxocobalamin aids in the brain and nervous system development and hematopoiesis during childhood. Adenosylcobalamin is important in myelin production and is involved in the metabolism of carbohydrates, amino acids, and fatty acids. As a result, the role of vitamin B12 emphasizes the clinical signs and symptoms of vitamin B12 deficiency, as well as the indications for using hydroxocobalamin. A cofactor; Methycobalamine for the enzyme methionine synthase, is required for the conversion of homocysteine to methionine. This activity is necessary for the synthesis of purines and pyrimidines, which are required for DNA synthesis and the formation of red blood cells (RBCs).

Mechanism of Inhibition of Cyanide Poisoning by Hydroxocobalamin

Mechanism of the antidote for cyanide poisoning involves cyanide binding to cytochrome c oxidase, an electron transport chain terminal complex. The synthesis of ATP and the use of cellular oxygen are both inhibited as a result of this process. Thus, cellular respiration is disrupted, and the cell dies quickly. Cobalt molecules in hydroxocobalamin can attach to and detoxify cyanide by intercepting it before it impairs cellular respiration. By eliminating cyanide from tissues, hydroxocobalamin quickly converts to cyanocobalamin. The cyanocobalamin is then excreted in the urine by the kidneys.

Therapeutic Indications

Vitamin B12 deficiency can be prevented and treated using hydroxocobalamin. Because it combines with cyanide to generate cyanocobalamin, it’s also utilized to treat illnesses linked to cyanide toxicity. Other uses of hydroxocobalamin include:

  • Nutritional optic neuropathy 
  • Pernicious anemia
  • Leber optic atrophy


Hydroxocobalamin Vitamin B12 is contraindicated in the following conditions:

  • Known hypersensitivity to hydroxocobalamin
  • Hypersensitivity to cobalt

Hydroxocobalamin Side effects

The following are some of the negative outcomes related to hydroxocobalamin parenteral administration:

  • Mild diarrhea
  • Urticaria
  • Skin rash
  • Anaphylactic reactions
  • Cross-sensitivity of hydroxocobalamin and cyanocobalamin

Hydroxocobalamin Interactions

1.      Ethinyl Estradiol

Hydroxocobalamin shows drug interaction with Ethinyl estradiol. Parallel use of Ethinyl estradiol and may cause a reduction in vitamin B12 levels in the blood.

2.      Mestranol

The use of mestranol with hydroxocobalamin may cause a drop in vitamin B12 levels in the blood.

Hydroxocobalamin use in Pregnancy and Lactation

As per NHS guidelines, Hydroxocobalamin is generally regarded as safe to take during pregnancy and breastfeeding. Although it passes through your milk, it is not detrimental to your infant.

Vitamin B12 Deficiency Symptoms

Fatigue, lack of energy, breathlessness, headaches, pale skin, hearing noises that originate from within the body rather than outside the environment, palpitations, loss of appetite, and weight loss are among some of the symptoms developed as a result of Vitamin B12 deficiency.

Vitamin B12 Deficiency Outcomes

Following are given some conditions which may result when someone experiences a deficiency of Vitamin B12.

  • Atrophic gastritis
  • Pernicious anemia
  • Crohn’s disease
  • Celiac disease
  • Glossitis
  • Inflamed tongue.

Natural Sources of Vitamin B12

Rich sources (food) of Vitamin B12 include meat, salmon and codfish, milk (other dairy products), and eggs. People who follow a strict vegan diet for a prolonged period of time without appropriate consumption of eggs and dairy products are susceptible to experience Vitamin B12 deficiency.


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