In the presence of neurological symptoms, following daily treatment, injections up to weekly or biweekly are indicated for six months before initiating monthly IM injections. Once clinical improvement is confirmed, maintenance supplementation of B12 will generally be needed for life. Cyanide poisoning
Hydroxocobalamin is first line therapy for people with cyanide poisoning. Hydroxocobalamin converts cyanide to the much less toxic cyanocobalamin. Cyanocobalamin is renally cleared. The use of hydroxocobalamin became first line due to its low adverse risk profile, rapid onset of action, and ease of use in the prehospital setting. Injectable hydroxocobalamin
Injection of hydroxocobalamin is used to rectify the following causes of vitamin B12 deficiency (list taken from the drug prescription label published by the U.S. Food and Drug Administration)

Dietary deficiency of vitamin B12 occurring in strict vegetarians and in their breastfed infants (isolated vitamin B12 deficiency is very rare)
Malabsorption of vitamin B12 resulting from damage to the stomach, where intrinsic factor is secreted, or damage to the ileum, where intrinsic factor facilitates vitamin B12 absorption. These conditions include tropical sprue and nontropical sprue (celiac disease). Inadequate secretion of intrinsic factor, resulting from lesions that destroy the gastric mucosa (which can be caused by ingestion of corrosives, extensive tumors, and conditions associated with gastric atrophy, such as multiple sclerosis, certain endocrine disorders, iron deficiency, and subtotal gastrectomy)
Structural lesions leading to vitamin B12 deficiency, including regional ileitis, ileal reactions, and malignancies
Competition for vitamin B12 by intestinal parasites or bacteria.
Treatment of this chronic disease was no longer seen as a mere slowing of "inexorable degeneration", but instead viewed through "a model of surveillance and early detection. ": 84 Orinase and other sulfonylureas emerged from European pharmaceutical research into antibiotics, specifically from attempts to develop sulfa compounds. One of the contenders for a new sulfa antibiotic had serious side effects during clinical trials at the University of Montpellier including blackouts, convulsions, and coma, side effects not observed with any other drugs in the sulfa cohort. An insulin researcher at the same university heard of these side effects and recognized them as common results of hypoglycemia. The resulting class of drugs for lowering blood sugar came to be known as the sulfonylureas, starting with Orinase and still in use today in other forms. Unfortunately for diabetics dependent on insulin as a treatment for their condition, this research at Montpellier occurred in the early 1940s and was significantly disrupted by the German occupation of France during World War II. Development of these compounds was taken over by German pharmaceutical companies, which were obviously disinclined to share their bounty with nations upon which they were waging war. The German research was, in turn, disrupted by Germanys defeat in 1945 and the partition of Germany into East and West Germany. The sulfonylureas were trapped in East Germany. In 1952, someone smuggled a sample to a West German pharmaceutical company and research resumed. Clinical trials in diabetics began in 1954 in Berlin.