From the Guidelines
The recommended dosage, route, and frequency of Vitamin B12 for optimal levels is hydroxocobalamin 1 mg intramuscularly every 2-3 months for lifelong maintenance, with higher frequencies and doses for those with deficiency or neurological involvement, as outlined in the British Obesity and Metabolic Surgery Society guidelines 1.
Key Considerations
- For individuals with vitamin B12 deficiency and neurological involvement, treatment should start with hydroxocobalamin 1 mg intramuscularly on alternate days until no further improvement is seen, then maintenance with 1 mg intramuscularly every 2 months 1.
- For those without neurological involvement, the recommendation is hydroxocobalamin 1 mg intramuscularly three times a week for 2 weeks, followed by maintenance treatment with 1 mg intramuscularly every 2-3 months for life 1.
- It is crucial to treat vitamin B12 deficiency immediately and avoid giving folic acid first, as it may mask underlying vitamin B12 deficiency and precipitate subacute combined degeneration of the spinal cord 1.
Important Points
- Regular blood tests are essential to monitor vitamin B12 levels and adjust dosing as needed.
- Vitamin B12 is vital for nerve function, DNA synthesis, and red blood cell formation, and its deficiency can lead to severe health issues if not addressed promptly.
- The body's ability to absorb vitamin B12 is limited, which necessitates higher doses and regular supplementation for those with deficiencies, especially after gastric surgery or in cases of pernicious anemia 1.
From the FDA Drug Label
Patients with pernicious anemia should be instructed that they will require monthly injections of Vitamin B12 for the remainder of their lives. Amounts of Vitamin B12 that are recommended by the Food and Nutrition Board, National Academy of Science-National Research Council for pregnant women (4 mcg daily) should be consumed during pregnancy. Amounts of Vitamin B12 that are recommended by the Food and Nutrition Board, National Academy of Science-National Research Council for lactating women (4 mcg daily) should be consumed during lactation. Intake in children should be in the amount (0.5 to 3 mcg daily) recommended by the Food and Nutrition Board, National Academy of Science-National Research Council.
The recommended dosage of Vitamin B12 for optimal levels is:
- 4 mcg daily for pregnant women 2
- 4 mcg daily for lactating women 2
- 0.5 to 3 mcg daily for children 2 The recommended route of administration is:
- Monthly injections for patients with pernicious anemia 2
- Oral administration for patients with dietary deficiencies 2 The recommended frequency of administration is:
- Monthly injections for patients with pernicious anemia 2
- Daily oral administration for patients with dietary deficiencies 2
From the Research
Recommended Dosage of Vitamin B12
- The recommended dosage of Vitamin B12 varies depending on the route of administration and the individual's needs.
- According to 3, parenteral regimens using 1000 micrograms of cyanocobalamin are recommended, with 5 or 6 biweekly injections for loading and once-a-month for maintenance.
- Oral therapy with 300-1000 micrograms per day may be therapeutically equivalent to parenteral therapy 3.
- High oral doses of B12 (1000 mcg and 2000 mcg) have been shown to be as effective as intramuscular administration in achieving haematological and neurological responses 4.
Route of Administration
- Both oral and intramuscular routes of administration have been shown to be effective in treating vitamin B12 deficiency 3, 4, 5.
- The oral route has been proven to be comparable to the intramuscular route for rectifying vitamin B12 deficiency 5.
Frequency of Administration
- The frequency of administration depends on the individual's needs and the route of administration.
- For parenteral regimens, once-a-month injections are recommended for maintenance 3.
- For oral therapy, daily doses of 300-1000 micrograms may be necessary 3.
- High oral doses of B12 (2000 mcg) daily, and then weekly and monthly, may be as effective as intramuscular administration in obtaining short-term haematological and neurological responses 4.
Type of Vitamin B12
- There are different forms of vitamin B12, including methylcobalamin, adenosylcobalamin, and hydroxocobalamin.
- Methylcobalamin is primarily involved in hematopiesis and development of the brain during childhood, while adenosylcobalamin is involved in carbohydrate, fat, and amino-acid metabolism 5.
- Treatment of vitamin B12 deficiency with a combination of methylcobalamin and adenosylcobalamin or hydroxocobalamin may be necessary 5.