Supplemental folic acid therapy in pernicious anemia: the effect on erythropoiesis and serum vitamin B12 concentrations in selected cases.

Abstract

Abstract 1.1. Administration of 30 μg of vitamin B 12 intramuscularly every two weeks increased the hemoglobin levels of only five of a group of twenty-two patients previously receiving 15 μg of crystalline vitamin B 12 every four weeks. None of eleven patients who received 20 μg of vitamin B 12 in the form of Liver Injection U.S.P. every two weeks was so benefited. 2.2. Supplemental folic acid did not alter hemoglobin levels; therefore folic acid deficiency as a limiting factor in hematopoiesis was shown not to exist in twenty-nine patients given adequate therapy with vitamin B 12 . 3.3. The serum vitamin B 12 level in twenty of thirty-five patients receiving 15 μg of vitamin B 12 once every four weeks was less than 100 μg per milliliter, which is characteristic of patients with pernicious anemia in relapse. It is greater than 100 μμg per milliliter in most patients receiving 30 μg of vitamin B 12 once every four weeks. Inasmuch as the serum vitamin B 12 concentration probably reflects tissue saturation, treatment with the larger dose of vitamin B 12 appears to be more nearly adequate. 4.4. Administration of folic acid adversely affected the serum vitamin B 12 level of eighteen of twenty-seven patients receiving 20 or 30 μg of vitamin B 12 intramuscularly every two weeks, possibly by accelerating the utilization of vitamin B 12 . Therefore, supplementation of inadequate intramuscular vitamin B 12 therapy with folic acid, in addition to being unnecessary for nearly all patients, may actually be inadvisable unless larger doses of vitamin B 12 are given.