From the Guidelines
To replace vitamin B12 deficiency, 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, as recommended by the British Obesity and Metabolic Surgery Society guidelines 1. When treating vitamin B12 deficiency, it is essential to prioritize the most recent and highest quality evidence, which suggests that hydroxocobalamin injections are the most effective way to replace the deficiency, especially in cases with possible neurological involvement.
- The treatment regimen may vary depending on the presence of neurological symptoms, with more frequent injections administered on alternate days until there is no further improvement, then every 2 months 1.
- It is crucial to address the underlying cause of the deficiency, whether it's poor diet, malabsorption issues, pernicious anemia, or medication effects, to prevent further complications.
- Dietary changes can help maintain vitamin B12 levels by consuming B12-rich foods like meat, fish, eggs, dairy products, and fortified cereals, or fortified plant milks and nutritional yeast for vegans.
- The British Obesity and Metabolic Surgery Society guidelines emphasize the importance of treating vitamin B12 deficiency immediately and seeking urgent specialist advice from a neurologist and haematologist if there is possible neurological involvement 1.
From the FDA Drug Label
In patients with Addisonian Pernicious Anemia, parenteral therapy with vitamin B12 is the recommended method of treatment and will be required for the remainder of the patient’s life. Treatment of Vitamin B12 Deficiency Thirty mcg daily for 5 to 10 days followed by 100 to 200 mcg monthly injected intramuscularly. Patients who have normal intestinal absorption may be treated with an oral therapeutic multivitamin preparation, containing 15 mcg vitamin B12 daily.
To replace vitamin B12 deficiency, the recommended treatment is:
- Parenteral therapy with vitamin B12 for patients with Addisonian Pernicious Anemia, which is required for the remainder of the patient's life.
- Intramuscular injection of 30 mcg daily for 5 to 10 days, followed by 100 to 200 mcg monthly for treatment of vitamin B12 deficiency.
- Oral therapeutic multivitamin preparation containing 15 mcg vitamin B12 daily for patients with normal intestinal absorption 2.
From the Research
Replacement Therapy for Vitamin B12 Deficiency
- Vitamin B12 deficiency can be treated with oral or parenteral (intramuscular) therapy, with both methods being effective in correcting the deficiency 3, 4, 5.
- Oral administration of high-dose vitamin B12 (1 to 2 mg daily) is as effective as intramuscular administration for correcting anemia and neurologic symptoms 4.
- Intramuscular therapy may lead to more rapid improvement and should be considered in patients with severe deficiency or severe neurologic symptoms 4.
Dosage and Administration
- The recommended dosage for parenteral therapy is 1000 micrograms of cyanocobalamin, 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.
- 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 5.
Special Considerations
- Patients with Crohn's disease and vitamin B12 deficiency may be effectively treated with oral cyanocobalamin, with a dose of 1 mg/day being commonly used 6.
- Patients who have had bariatric surgery should receive 1 mg of oral vitamin B12 per day indefinitely 4.
- The oral route has been shown to be comparable to the intramuscular route for rectifying vitamin B12 deficiency, and may be a more convenient and cost-effective option 5, 7.