What is the recommended dose of Cyanocobalamin (Vitamin B12)?

From the Guidelines

Vitamin B12 deficiency should be treated with hydroxocobalamin 1 mg intramuscularly administered on alternate days until there is no further improvement, then hydroxocobalamin 1 mg intramuscularly administered every 2 months for patients with neurological involvement, and 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 for patients without neurological involvement. The dosing of cyanocobalamin (vitamin B12) is crucial in treating vitamin B12 deficiency, which can lead to megaloblastic anemia and neurological complications if left untreated 1.

Key Considerations

• The treatment of vitamin B12 deficiency with possible neurological involvement requires immediate attention and urgent specialist advice from a neurologist and haematologist 1.
• Hydroxocobalamin is the preferred form of vitamin B12 for treatment, especially in cases with neurological involvement or impaired absorption 1.
• The maintenance dose of hydroxocobalamin is 1 mg intramuscularly every 2–3 months for life for patients without neurological involvement, and every 2 months for patients with neurological involvement 1.

Important Details

• Folic acid deficiency may indicate non-adherence with the daily multivitamin and mineral supplement or malabsorption, and some medications may affect folic acid levels 1.
• Treatment of folic acid deficiency requires oral folic acid 5 mg daily for a minimum of 4 months, but only after excluding vitamin B12 deficiency 1.
• Vitamin B12 plays a critical role in nerve function, DNA synthesis, and red blood cell formation, making its deficiency a significant health concern that requires prompt and appropriate treatment 1.

From the FDA Drug Label

Doses of cyanocobalamin exceeding 10 mcg daily may produce hematologic response in patients with folate deficiency. Patients with pernicious anemia should be informed that they will require monthly injections of vitamin B12 for the remainder of their lives. The need for vitamin B12 is increased by pregnancy and lactation. 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 cyanocobalamin dose is:

• 10 mcg daily for patients with folate deficiency
• monthly injections for patients with pernicious anemia
• 4 mcg daily for pregnant women
• 4 mcg daily for lactating women
• 0.5 to 3 mcg daily for children 2

From the Research

Cyanocobalamin Dose

• The recommended dose of cyanocobalamin varies depending on the severity of the deficiency and the route of administration 3, 4, 5.
• For parenteral regimens, a dose of 1000 micrograms of cyanocobalamin is recommended, with 5 or 6 biweekly injections for loading and once-a-month for maintenance 3.
• Oral therapy with 300-1000 micrograms per day may be therapeutically equivalent to parenteral therapy 3.
• A study found that oral supplementation with 1000 μg/d of cyanocobalamin improved vitamin B12 deficiency in patients with pernicious anemia 4.
• Another study suggested that daily doses of 647 to 1032 μg of cyanocobalamin were associated with 80% to 90% of the estimated maximum reduction in the plasma methylmalonic acid concentration 5.
• The use of high-dose oral B12 at different frequencies may be considered for long-term treatment, and prophylactic B12 supplementation should be considered for specific high-risk groups 6.

Route of Administration

• Both parenteral and oral routes of administration are effective for treating vitamin B12 deficiency 3, 7, 4, 5.
• The oral route is comparable to the intramuscular route for rectifying vitamin B12 deficiency 7.
• Parenteral B12 is regarded as the first choice for patients with acute and severe manifestations of B12 deficiency 6.

Treatment Duration

• The treatment duration for vitamin B12 deficiency varies depending on the severity of the deficiency and the response to treatment 4, 6.
• A study found that oral supplementation with 1000 μg/d of cyanocobalamin for 1 year improved vitamin B12 deficiency in patients with pernicious anemia, with no patients showing vitamin B12 deficiency by the end of the follow-up period 4.