Our Comment:
Four injections per year of hydroxocobalamin are normally sufficient to treat pernicious anemia adequately. The greater part of injected cyanocobalamin is excreted in urine; hydroxocobalamin is retained in the body longer. Good reasons why cyanocobalamin should be given anyway do not exist. Irrational therapy is often conducted with vitamin B12. On the other hand, it is important not to overlook a deficiency (especially in the elderly).