Cyanocobalamin Injection (Vitamin B12)


Indications for Prior Authorization:

  • 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
  • Vitamin B12 supplementation to reduce toxicity associated with pemetrexed or pralatrexate
  • 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.

Prior authorization criteria:

  • Prior authorization required for any dosing greater than cyanocobalamin 1000mcg once monthly
  • Diagnosed vitamin B12 deficiency, AND
  • Has tried and failed oral cyanocobalamin as evidenced by medical record documentation (does not apply to pernicious anemia)


  • Pernicious anemia: parenteral vitamin B12 is the recommended treatment and will be required for the remainder of the patient's life. 
    • 100 mcg IM daily for 6 or 7 days; with clinical improvement and reticulocyte response, the same dose may be given on alternate days for seven doses, then every 3 to 4 days for another 2 to 3 weeks. 
    • Maintenance: 100 mcg monthly
  • Patients with normal intestinal absorption: when the oral route is not adequate, initial treatment similar to that for patients with pernicious anemia may be indicated depending on deficiency severity.
  • Supplementation to reduce toxicity associated with pemetrexed: IM: 1000 mcg every 9 weeks, beginning 1 to 3 weeks prior to pemetrexed treatment initiation; continue for 3 weeks after last pemetrexed dose.
  • Supplementation to reduce toxicity associated with pralatrexate: IM: 1000 mcg every 8 to 10 weeks; begin cyanocobalamin within 10 weeks prior to pralatrexate treatment initiation.


  • One year

Last review date: June 10, 2019

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