Hydroxocobalamin for initial and long-term therapy for vitamin B12 deficiency.

Seventeen patients were treated for vitamin B12 deficiency with i.m. injection of 1 mg hydroxocobalamin every three months as maintenance therapy for eight to 20 years after an initial depot treatment of one or two series of five i.m. injections on alternate days. In three of four patients given two depot series less than or equal to 3 months apart, and with no antibody to transcobalamin II (TC II) detected previously, abnormally high values of serum cobalamins were measured at the end of injection intervals after seven to 12 years. No increase in unsaturated B12 binding capacity (UB12BC) was found in contrast to findings in patients given identical therapy, in whom an early increase above the normal level occurred associated with antibody to TC II. One depot series followed by i.m. injection of 1 mg hydroxocobalamin every third month secured values within the normal range for serum cobalamin, UB12BC and total B12 binding capacity (TB12BC).