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an analogue of cyanocobalamin (vitamin B12) having exceptionally long-acting hematopoietic activity; used in the treatment of pernicious anemia and other macrocytic anemias.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.


Vitamin B12b, differing from cyanocobalamin (vitamin B12) in the presence of a hydroxyl ion in place of the cyanide ion at the sixth coordinate position on the cobalt atom.
See also: vitamin B12.
Synonym(s): hydroxocobemine
Farlex Partner Medical Dictionary © Farlex 2012


A chemical compound, also called vitamin B12a, which is the immediate precursor to cyanocobalamin (vitamin B12) in the body and that has also been investigated as an antidote in cyanide poisoning, although it is not currently approved for such use in the U.S.
See also: amyl nitrite, sodium nitrite, sodium thiosulfate
Synonym(s): hydroxocobalamin.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012


Vitamin B12. This is the specific treatment for PERNICIOUS ANAEMIA and is highly effective unless neurological damage has already occurred. The drug is on the WHO official list. Brand names are Cobalin-H and Neo-Cytamen.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005
References in periodicals archive ?
Vitamin- B12 has three analogues -cyanocobalamin with short half-life- hydroxocobalamin with the longest half-Life, recommended by the WHO and all the 'Drug Regulatory Authorities' of the scientifically advanced countries and the authentic scientific literature.
Laboratory interferences with the newer cyanide antidote: hydroxocobalamin. Semin Diagn Pathol.
Although the recommended treatment for acute cyanide toxicity is hydroxocobalamin (injectable vitamin B12) (4), persons who went to health care facilities were managed on intravenous antibiotics and oral rehydration salts.
She was being treated regularly with levothyroxine and hydroxocobalamin injections.
In this research, hydroxocobalamin (namely vitamin B12) had mutual effect with MTR and affected transmethylation of methyl cobalamin to HCY (homocysteine) and consequently it gave play to neuroprotection.
The antidote, hydroxocobalamin, classically induces an abnormal reddish discoloration of renal allografts, and oxalate crystals on histologic examination are common.
He was given an intravenous infusion over a 10-minute period that contained 1 g of magnesium chloride hexahydrate, 2.5 ml of 10% calcium gluconate, 1,000 [micro]g of hydroxocobalamin, 100 mg of pyridoxine, 250 mg of dexpanthenol, and 1 ml of B complex 100.
For patients with vitamin [B.sub.12] deficiency, guidelines from the National Health Service in the United Kingdom and the British Society for Haematology recommend treatment with IM hydroxocobalamin, 1,000 IU, 3 times weekly, for 2 weeks.
Six medicines without licensing by Anvisa were incorporated in the period: Biotin (biotidinase deficiency), injectable doxycycline and chloramphenicol oral suspension (spotted fever), hydroxyurea 100mg tablet (sickle cell disease), hydrocortisone cypionate (congenital adrenal hyperplasia), and hydroxocobalamin hydrochloride (cyanide poisoning).
Prevention of hydrogen sulfide (H2S)-induced mouse lethality and cytotoxicity by hydroxocobalamin (vitamin B(12a)).
When treated appropriately, hydroxocobalamin, a form of Vitamin B12, can form a hexadentate complex, including one molecule of NO, and is able to successfully deliver NO to cancer cells following TCP-II receptor binding, endocytosis, and lysosome-mediated NO release.
Both parenteral and oral doses of cyanocobalamin, hydroxocobalamin, or methylcobalamin may be used in pernicious anemia related cobalamin deficiency [70, 71], although hydroxocobalamin administration is associated with better uptake and storage compared to other forms [72].