Vitamin B12 Absorption by Inhalation

Cyanocobalamin in the form of an aerosol was inhaled by normal subjects, patients with pulmonary diffusion defects and patients with vitamin B₁₂ deficiency. In all groups there was a rapid increase in serum B₁₂ levels suggesting that absorption had occurred by diffusion through the lung alveoli.
Six patients with pernicious anaemia given daily inhalations showed complete clinical and haematological remission and a group of six patients with B ₂ deficiency were maintained in remission for 12 months. While effective, this method of administration of vitamin B₁₂ is not regarded as superior to that of injections and is therefore considered to have no therapeutic application. The possibility of inducing pulmonary damage is considered.