From the Guidelines
To treat low vitamin B12, 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 low vitamin B12, it is essential to consider the severity of the deficiency and the presence of neurological involvement.
- For patients with neurological involvement, hydroxocobalamin 1 mg intramuscularly should be administered on alternate days until there is no further improvement, then hydroxocobalamin 1 mg intramuscularly every 2 months 1.
- For patients with no neurological involvement, hydroxocobalamin 1 mg intramuscularly three times a week for 2 weeks, followed by maintenance treatment with 1 mg intramuscularly every 2–3 months is recommended 1. The treatment approach may vary depending on the underlying cause of the deficiency, such as malabsorption or pernicious anemia.
- Patients with ileal involvement or resection may require lifelong treatment with vitamin B12 injections, typically 1000 mg intramuscularly every month 1. It is crucial to monitor treatment effectiveness through blood tests and symptom improvement, as addressing vitamin B12 deficiency promptly helps prevent neurological damage and anemia 1.
From the FDA Drug Label
INDICATIONS AND USAGE Cyanocobalamin is indicated for vitamin B12 deficiencies due to malabsorption which may be associated with the following conditions: Addisonian (pernicious) anemia Gastrointestinal pathology, dysfunction, or surgery, including gluten enteropathy or sprue, small bowel bacteria overgrowth, total or partial gastrectomy Fish tapeworm infestation Malignancy of pancreas or bowel Folic acid deficiency Requirements of vitamin B12 in excess of normal (due to pregnancy, thyrotoxicosis, hemolytic anemia, hemorrhage, malignancy, hepatic and renal disease) can usually be met with oral supplementation.
Treatment for low B12 involves addressing the underlying cause of the deficiency.
- For cases due to malabsorption, treatment may include:
- Surgical correction of anatomic lesions
- Expulsion of fish tapeworm
- Discontinuation of drugs leading to vitamin malabsorption
- Use of a gluten-free diet in nontropical sprue
- Administration of antibiotics in tropical sprue
- For cases with requirements of vitamin B12 in excess of normal, treatment may include oral supplementation 2 3. Cyanocobalamin Injection, USP or methylcobalamin (PO) may be used to treat vitamin B12 deficiencies.
From the Research
Treatment Options for Low B12
- 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 leads to more rapid improvement and should be considered in patients with severe deficiency or severe neurologic symptoms 4
- Oral cyanocobalamin provides effective acute and maintenance treatment for vitamin B12 deficiency caused by Crohn's disease with or without ileum resection 5
- A combination of methylcobalamin and adenosylcobalamin or hydroxocobalamin can be used to treat vitamin B12 deficiency, as both are essential and have distinct metabolic fates and functions 6
Dosage and Administration
- The most used dose of oral cyanocobalamin is 1 mg/day, but there are no significant differences in treatment effectiveness depending on the dose used (≥1 mg/24 h vs. <1 mg/24 h) 5
- Oral vitamin B12 replacement at 1000 μg daily is adequate to replace vitamin B12 levels in patients with pernicious anemia 7
- Patients who have had bariatric surgery should receive 1 mg of oral vitamin B12 per day indefinitely 4
Special Considerations
- Patients older than 50 years and vegans or strict vegetarians should consume foods fortified with vitamin B12 or take vitamin B12 supplements, as absorption rates improve with supplementation 4
- Screening for vitamin B12 deficiency may be warranted in patients with one or more risk factors, such as gastric or small intestine resections, inflammatory bowel disease, or use of certain medications 4