What is the treatment for Vitamin B12 deficiency?

Treatment of Vitamin B12 Deficiency

The recommended treatment for vitamin B12 deficiency is hydroxocobalamin 1 mg intramuscularly on alternate days until no further improvement for patients with neurological involvement, or 1 mg intramuscularly three times weekly for 2 weeks for those without neurological involvement, followed by maintenance with 1 mg intramuscularly every 2-3 months lifelong. 1

Diagnosis and Assessment

Before initiating treatment, proper diagnosis is essential:

• Vitamin B12 deficiency is confirmed when:

  • Total B12 <180 ng/L or active B12 <25 pmol/L 1
  • For indeterminate results (Total B12 180-350 ng/L), test methylmalonic acid and homocysteine levels 1

• High-risk populations requiring monitoring:

  • Elderly (10-40% prevalence)
  • Vegetarians and vegans
  • Post-bariatric surgery patients
  • Patients with malabsorption conditions (ileal resection >20 cm, Crohn's disease)
  • Patients on metformin 1

Treatment Protocol

For Patients with Neurological Involvement:

1. Initial Treatment: Hydroxocobalamin 1 mg intramuscularly on alternate days until no further improvement 1
2. Maintenance: 1 mg intramuscularly every 2-3 months lifelong 1

For Patients without Neurological Involvement:

1. Initial Treatment: Hydroxocobalamin 1 mg intramuscularly three times weekly for 2 weeks 1
2. Maintenance: 1 mg intramuscularly every 2-3 months lifelong 1

Alternative Approaches:

• Standard maintenance regimen: 1000 mcg intramuscularly monthly, indefinitely 1
• Oral high-dose supplementation: 1000-2000 μg daily (effective for most patients without severe neurological involvement) 1
• Sublingual B12: Comparable efficacy to intramuscular administration with better compliance and cost-effectiveness 1

Special Considerations

For Specific Patient Groups:

• Ileal resection >20 cm: Vitamin B12 supplementation with 1000 mcg IM monthly, indefinitely 1
• Pregnancy and lactation: 4 mcg daily is recommended 2
• Children: 0.5 to 3 mcg daily as recommended by the Food and Nutrition Board 2

Important Precautions:

• Urgent treatment needed: Vitamin B12 deficiency allowed to progress for >3 months may produce permanent degenerative spinal cord lesions 2
• Avoid folic acid alone: Do not give folic acid before treating B12 deficiency, as it may mask the deficiency and precipitate subacute combined degeneration of the spinal cord 1
• Monitor potassium: During initial treatment of pernicious anemia, serum potassium must be observed closely the first 48 hours 2

Monitoring Response

1. Assess response after 3 months by measuring serum B12 levels 1
2. Monitor platelet count until normalization 1
3. Monitor for improvement in neurological symptoms, including memory function 1
4. Periodically assess B12 levels during maintenance therapy 1

Route of Administration Considerations

• While intramuscular injections have traditionally been the mainstay of treatment, oral replacement therapy (1-2 mg daily) can be effective in many cases 3
• Intramuscular therapy leads to more rapid improvement and should be considered in patients with severe deficiency or severe neurologic symptoms 3
• Recent evidence suggests that up to 50% of individuals with malabsorption may require individualized injection regimens with more frequent administration (ranging from daily or twice weekly to every 2-4 weeks) to remain symptom-free 4

Common Pitfalls to Avoid

1. Delaying treatment in patients with neurological symptoms
2. Using folic acid alone in B12 deficiency
3. Failing to identify and address the underlying cause of B12 deficiency
4. Inadequate follow-up monitoring
5. "Titrating" injection frequency based solely on serum B12 or MMA levels rather than clinical response 4