Vitamin B12 Injection Medication Monograph

Methylcobalamin and cyanocobalamin are B-vitamins also known as Vitamin B12. Lipo-B contains cyanocobalamin as well as methionine, inositol, and choline. Vitamin B12 is found in food like meat, fish, shellfish and dairy products

Indications: Vitamin B12 deficiency: Treatment of pernicious anemia, vitamin B12 deficiency due to dietary deficiencies, gastrointestinal malabsorption, folic acid deficiency, parasitic infestation, inadequate secretion of intrinsic factor, and inadequate utilization of B12 (eg, during neoplastic treatment); treatment of increased B12 requirements due to pregnancy, thyrotoxicosis, hemorrhage, malignancy, liver or kidney disease

Renal Dosing: There are no dosage adjustments provided in the manufacturer’s labeling

Hepatic Impairment: There are no dosage adjustments provided in the manufacturer’s labeling

Contraindications: to vitamin B12, cobalt, or any component of the formulation

Warnings/Precautions:

CNS effects: Vitamin B12 deficiency for >3 months results in irreversible degenerative CNS lesions; neurologic manifestations will not be prevented with folic acid unless vitamin B12 is also given

Hypokalemia: According to the manufacturer, treatment of severe vitamin B12 megaloblastic anemia may result in severe hypokalemia, sometimes fatal, due to intracellular potassium shift upon anemia resolution; however, in more recent experience, while some patients may experience hypokalemia, this is unlikely to be significant

Leber disease: Patients with Leber disease who received B12 treatment have suffered from severe rapid optic atrophy

Thrombocytosis: Treatment of severe vitamin B12 megaloblastic anemia may result in thrombocytosis

Polycythemia vera: Vitamin B12 deficiency masks signs of polycythemia vera; vitamin B12 administration may unmask this condition

Drug Interactions: Chloramphenicol (Systemic): May diminish the therapeutic effect of Vitamin B12. Colchicine: May decrease the serum concentration of Vitamin B12. Heavy ethanol consumption >2 weeks may impair vitamin B12 absorption. Please speak with your doctor or pharmacist about other possible drug interactions as this list is not all-inclusive

Adverse Reactions: Dizziness, headache, nervous and excitable, upset stomach or throwing up, diarrhea

Storage: Lipo-B and cyanocobalamin should be stored at room temperature

Powdered Methylcobalamin should be stored at room temperature until it is mixed with water. Once mixed, methylcobalamin should be stored in the refrigerator

Patient Education:

What should I tell my doctor about before taking this medication?

Leber disease, blood problems, pregnancy, other medications you take including those that are over-the-counter

What side effects should I call my doctor about right away?

Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat; swelling, warmth, numbness, change of color, or pain in a leg or arm; very loose stools (diarrhea); feeling very tired or weak; chest pain; shortness of breath, a big weight gain, or swelling in the arms or legs; change in balance; a burning, numbness, or tingling feeling that is not normal; any unexplained bruising or bleeding