[Intranasal cyanocobalamin; an effective and safe therapeutic alternative].

Vitamin B12 or cobalamin deficiency is a common nutritional disorder, in which the early recognition and treatment is critical since it is a reversible cause of bone marrow failure and demyelinating nervous system disease. Insufficient intake of vitamin along with anatomical or functional disorders of the stomach, pancreas and terminal ileum are the most frequent causes of the deficit. We present three cases of patients with cobalamin deficiency secondary to intestinal malabsorption after bariatric surgery, in relation to autoimmune process and inflammatory bowel disease mechanisms respectively, which conditioned a lack of response to treatment with high-dose oral cyanocobalamin. They also had contraindication to intramuscular administration of cyanocobalamin by the use of oral anticoagulants. In such patients, the use of an inhaled formulation cyanocobalamin provides an adequate absorption, normalizing serum cobalamin and without the existence of side effects.