From the Guidelines
For vitamin B12 deficiency, the recommended dose is hydroxocobalamin 1 mg intramuscularly, with the frequency of administration depending on the presence of neurological involvement. The treatment regimen varies based on whether there is neurological involvement.
- For people with vitamin B12 deficiency and possible neurological involvement, hydroxocobalamin 1 mg intramuscularly should be administered on alternate days until there is no further improvement, then hydroxocobalamin 1 mg intramuscularly administered every 2 months 1, 2.
- For people with vitamin B12 deficiency and no neurological involvement, hydroxocobalamin 1 mg intramuscularly should be administered three times a week for 2 weeks, followed by maintenance treatment with 1 mg intramuscularly every 2–3 months for life 1, 2. It is essential to treat vitamin B12 deficiency immediately, especially in cases with possible neurological involvement, to prevent irreversible nerve damage 1, 2. Urgent specialist advice from a neurologist and haematologist should be sought if there is possible neurological involvement, such as unexplained sensory and/or motor and gait symptoms 1, 2. Folic acid deficiency may also be present, but it is crucial to exclude vitamin B12 deficiency before treating folic acid deficiency to avoid masking the underlying condition 1. Treatment effectiveness should be monitored through symptom improvement and normalization of B12 levels, with hematologic response typically seen within days to weeks. The body requires B12 for DNA synthesis, red blood cell formation, and neurological function, making prompt treatment essential to prevent irreversible nerve damage.
From the FDA Drug Label
Patients with pernicious anemia should be informed that they will require monthly injections of vitamin B12 for the remainder of their lives. The recommended dose of Vitamin B12 in cases of Vitamin B12 deficiency is not explicitly stated in terms of a specific dose, but it is mentioned that patients with pernicious anemia will require monthly injections of vitamin B12.
- The text does mention that doses of cyanocobalamin exceeding 10 mcg daily may produce hematologic response in patients with folate deficiency, but this is not a direct recommendation for Vitamin B12 deficiency treatment.
- Additionally, the text mentions that the Food and Nutrition Board recommends 4 mcg daily for pregnant and lactating women, and 0.5 to 3 mcg daily for children, but these are general recommendations and not specific to treating Vitamin B12 deficiency 3.
From the Research
Recommended Dose of Vitamin B12
The recommended dose of Vitamin B12 in cases of Vitamin B12 deficiency varies depending on the cause of the deficiency and the individual's response to treatment.
- For individuals with B12 deficiency due to malabsorption, the British National Formulary guidelines suggest 1000 µg intramuscular hydroxocobalamin once every two months after the initial loading 4.
- Some studies recommend parenteral regimens using 1000 micrograms cyanocobalamin: 5 or 6 biweekly injections for loading, and once-a-month for maintenance 5.
- Oral therapy with 300-1000 micrograms per day may be therapeutically equivalent to parenteral therapy 5.
- A daily dose of 1 mg vitamin B12 is also recommended for efficient treatment 6.
- Oral administration of high-dose vitamin B12 (1 to 2 mg daily) is as effective as intramuscular administration for correcting anemia and neurologic symptoms 7.
- A systematic review suggests that oral vitamin B12 replacement, at a daily dose of 1000 μg (1 mg), is adequate to normalize serum vitamin B12 levels and cure main clinical manifestations related to vitamin B12 deficiency in GI disorders 8.
Individualized Treatment
It is essential to note that treatment follows an individualized approach, based on the cause of the deficiency, and tailored to help someone become and remain symptom-free 4.
- Clinical and patient experience strongly suggests that up to 50% of individuals require individualized injection regimens with more frequent administration, ranging from daily or twice weekly to every 2-4 weeks, to remain symptom-free and maintain a normal quality of life 4.
- Intramuscular therapy leads to more rapid improvement and should be considered in patients with severe deficiency or severe neurologic symptoms 7.