Hydroxocobalamin

Hydroxocobalamin or also vitamin B12a is a synthetically produced (in the laboratory) active substance of vitamin B12. It is related to cyanocobalamin, i.e. vitamin B12, but has a higher protein binding and thus a better depot effect. Depots have the advantage that they are stored in the body (depot) and repeatedly release small amounts of the active substance into the bloodstream without further administration (application).

Hydroxocobalamin belongs to the group of cobalamins, which owe their name to the cobalt atom in their molecular structure. Hydroxocobalamin has a deep red color, is crystalline (crystal-forming), and has hydrophilic (hygroscopic) properties. Hydroxocobalamin, like the other B-group vitamins, is water-soluble and contains cobalt as its central atom. It is used to treat vitamin B12 deficiency and as an antidote for hydrogen cyanide poisoning.

Hydroxocobalamin is a prodrug, i.e. an active ingredient that is present in an inactive form and is only converted into the active form in the body after transformation. It is converted in the body to methylcobalamin and 5-deoxyadenosylcobalamin. Both are active forms of vitamin B12 and can be stored in this form in the body.

Hydroxocobalamin is taken up (absorbed) in the gastrointestinal tract, specifically in the lower part of the ileum (section of the small intestine). It is stored in the liver and is excreted in the urine.

Vitamin B12 is a key building block in metabolism. It is needed in blood formation (hematopoiesis), cell division, myelin formation (an insulating layer of nerve cells in the brain) and nucleic acid synthesis (synthesis of the components of human DNA).

Hydroxocobalamin is used to treat vitamin B12 deficiency, poor performance, fatigue and difficulty concentrating. It is used as an ointment for the treatment of psoriasis, as a dietary supplement and as an antidote for hydrocyanic acid poisoning. Hydroxocobalamin is found in meat, fish, eggs and milk.

In cases of hydrogen cyanide poisoning, the hydrogen cyanide is bound to the hydroxocobalamin and then excreted through the kidneys. Hydrogen cyanide poisoning occurs mainly in smoke inhalation, especially in indoor fires.

Hydroxocobalamin is responsible for the formation of methionine in the body. Methionine is used for the production (synthesis) of the DNA and RNA building blocks adenine, guanine and thymidine. If hydroxocobalamin is lacking, there is a deficiency of these building blocks, resulting in impaired cell division activity in the bone marrow. This leads to the absence of various blood cells, of which the deficiency of red blood cells (erythrocytes) is most noticeable.

Always take hydroxocobalamin exactly as described in the package leaflet or as advised by your doctor.

The recommended daily requirement for adults is 3 mcg daily.

The usual dose for the treatment of hydrogen cyanide poisoning is 5 g i.v. (i.e., administration via the vein) in adults within 25-30 minutes.

For hydrogen cyanide poisoning in children, 70 mg/kg body weight is recommended.

The following side effects may occur:

Interactions may occur if the following drugs are taken at the same time:

• Drugs for the treatment of diabetes (antidiabetics) of the biguanide type e.g. metformin may affect the absorption of hydroxocobalamin.
• p-aminosalicylic acid may affect the absorption of hydroxocobalamin
• Alcohol abuse may lower hydroxocobalamin levels

In general, hydroxocobalamin should not be taken concurrently with other medications because other agents may inhibit the absorption of hydroxocobalamin into the body.

Hydroxocobalamin must not be taken in the following cases:

• in case of allergy to hydroxocobalamin
• in case of Leber's optic atrophy

Hydroxocobalamin can be administered from the completed 1st year of life.

Hydroxocobalamin can be taken both during pregnancy and while breastfeeding. There are no known mutagenic or fertility-damaging effects. Hydroxocobalamin passes into breast milk.

Vitamin B12 was first described in 1926. Dorothy Crowfoot Hodgkin clarified its chemical structure shortly afterwards, for which she received the Nobel Prize in Chemistry in 1964. The first total synthesis was carried out by Albert Eschenmoser and Robert B. Woodward. Vitamin B12 is a very large molecule and is still considered one of the largest ever total synthesized.