Cyanocobalamin is also used to perform the Schilling test to check ability to absorb vitamin B12.Cyanocobalamin is also produced in the body (and then excreted via urine) after intravenous hydroxycobalamin is used to treat cyanide poisoning. Side effects
Possible side effects of cyanocobalamin injection include allergic reactions such as hives, difficult breathing; redness of the face; swelling of the arms, hands, feet, ankles or lower legs; extreme thirst; and diarrhea. Less-serious side effects may include headache, dizziness, leg pain, itching, or rash.Treatment of megaloblastic anemia with concurrent vitamin B12 deficiency using B12 vitamers (including cyanocobalamin), creates the possibility of hypokalemia due to increased erythropoiesis (red blood cell production) and consequent cellular uptake of potassium upon anemia resolution. When treated with cyanocobalamin, patients with Lebers disease may develop serious optic atrophy, possibly leading to blindness. Chemistry
Vitamin B12 is the "generic descriptor" name for any vitamers of vitamin B12. Animals, including humans, can convert cyanocobalamin to any one of the active vitamin B12 compounds.Cyanocobalamin is one of the most widely manufactured vitamers in the vitamin B12 family (the family of chemicals that function as B12 when put into the body), because cyanocobalamin is the most air-stable of the B12 forms. It is the easiest to crystallize and therefore easiest to purify after it is produced by bacterial fermentation. It can be obtained as dark red crystals or as an amorphous red powder. Cyanocobalamin is hygroscopic in the anhydrous form, and sparingly soluble in water (1:80). It is stable to autoclaving for short periods at 121 °C (250 °F).
Chondrodermatitis nodularis chronica helicis is a small, nodular, tender, chronic inflammatory lesion occurring on the helix of the ear, most often in men. : 610  it often presents as a benign painful erythematous nodule fixed to the cartilage of the helix or antihelix of the external ear. Although the exact cause of the condition is unknown, it has been linked to head pressure on the ear while sleeping. Treatment options include the use of pressure-relieving devices or, in cases where that is not an option, surgery. See also
List of cutaneous conditions


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