Hydroxocobalamin (Vitamin B12) Injectable 2mg/mL, 10mL

Cobalamins are vitamin B12 which can only be synthesized by microorganisms and can only be sourced from animal product-based diet. Deficiency of cobalamin can cause megaloblastic anaemia which could be related to deficient intake of vitamin B12 or deficient intrinsic factor, among other factors. The type of anaemia, resulting from lack of intrinsic factor is referred to as pernicious anaemia. 1

Hydroxocobalamin (OHCbl) is a natural form of vitamin B12 which is available commercially. It is administrated parenterally either as an intravenous or intramuscular injection. This form of cobalamin is bioidentical to the B12 forms occurring in human physiology. 2 Initially present as a manufacturing impurity and result of photolysis in commercial cyanocobalamin (under the trade name Cytamen), 3 hydroxocobalamin was later found to be superior for many clinical conditions.

Doses of OHCbl are quite efficient for prevention and treatment of pernicious anaemia, as an antidote in cases of cyanide poisoning as well as for the treatment of Leber’s optic atrophy and tobacco amblyopia. Pernicious anaemia is a fatal condition where deficiency of vitamin B12 affects generation of healthy red blood cells and proper functioning of nervous system. 4 In some individuals, an auto-immune response, inhibits production of a protein called intrinsic factor which is present in normal stomach secretion. It is responsible for vitamin B12 absorption and its absence causing clinical manifestation of its deficiency. Surgery involving stomach areas where cells responsible for intrinsic factor are affected could also lead to loss of B12 absorption. Besides this, several diseases like celiac disease, Crohn’s disease as well as HIV can interfere with vitamin B12 absorption. Others causes include wrong types of bacteria in small intestine, some antibiotics and B12 feeding tapeworm. 5

OHCbl is found to be safe and cost effective along with being efficient against pernicious anaemia to be listed as an anti-anaemic in the list of essential medicines for children published by W.H.O. 6

As an antidote for cyanide poisoning, hydroxocobalamin has shown many benefits over alternative antidotes. It has a very rapid response, its by-products are non-toxic and can be easily eliminated from the body, it can be used safely even with non-poisoned patients and it does not affect oxygen carrying capability of blood. It has a long history of being used as an anti-dote safely against cyanide poisoning. 7 The only limitation is that it needs to be administered intravenously for a significant period of time and might need a hospital setting.

Tobacco amblyopia is caused by tobacco consumption and can be treated with hydroxocobalamin. A notable difference of improved visual acuity and color vision was reported when OHCbl was administrated IM in patients suffering from it and the performance was superior to cyanocobalamin.