Maintenance therapy of pernicious anemia with vitamin B12

Abstract Patients with pernicious anemia were given maintenance therapy with crystalline vitamin B 12 , and a "concentrate" containing vitamin B 12 and B 12b for periods up to sixteen months. In the dosages used, these substances were as effective as purified liver extract. An average daily dose of 1 μg given intramuscularly at intervals of three or four weeks appeared to be sufficient to maintain normal erythrocyte levels and to prevent the development or progression of neurologic or lingual lesions. In previous experiments, the concentrate was less effective than the crystalline preparation, but with the concentrates available now there is probably no significant difference. Mild macrocytosis persisted in many of the patients and was not altered by the intramuscular administration of purified liver extract nor by the addition of daily oral doses of folic acid. Comparison of the treated patients with a series of "normals" from the literature indicates that the relationship of the erythrocyte level to hematocrit value in the two series is different, even when treated patients have high "normal" blood values. This suggests the possibility that neither vitamin B 12 , purified liver extract, nor folic acid given singly or in combination completely corrects the erythrocyte abnormality in pernicious anemia and suggests that some other substance(s) may be necessary in addition. From the practical standpoint, however, treatment with sufficient amounts of vitamin B 12 , B 12 concentrates, or purified liver extract maintains normal erythrocyte levels and prevents development or progression of neurologic and lingual lesions.