Indications & Uses
Vitamin B12 is used to treat pernicious anemia and Vitamin B12 deficiency caused by low dietary intake. It is also indicated for thyrotoxicosis, hemorrhage, malignancy, liver or kidney disease, gastric bypass surgery, total or partial gastrectomy, gluten enteropathy (sprue), folic acid deficiency, and macrocytic anaemia.
Dosage Reference
Reference Information Only
Dosages shown are general references from official sources. Always consult your doctor or pharmacist for personalized dosing.
Adults:
Usual Adult Dose for Pernicious Anemia: Initial dose, 1000 mcg by intramuscular or deep subcutaneous injection once daily for 6 to 7 days. If clinical improvement and reticulocyte response are seen from the above dosing, give 100 mcg every other day for 7 doses, then 100 mcg every 3 to 4 days for 2 to 3 weeks, then a maintenance dose of 100 to 1000 mcg monthly. Administer concomitant folic acid if needed. Chronic treatment should be done with an oral preparation in patients with normal intestinal absorption. Usual Adult Dose for B12 Nutritional Deficiency: 25 to 2000 mcg orally daily. Usual Adult Dose for Schilling Test: 1000 mcg intramuscularly is the flushing dose. Usual Pediatric Dose for B12 Nutritional Deficiency: 0.5 to 3 mcg daily.
Side Effects
Arthralgia (12%), Dizziness (12%), Headache (12%), Nasopharyngitis (12%), Anaphylaxis, Angioedema, Congestive heart failure, Peripheral vascular disease,Pulmonary edema, Diarrhea, Dyspepsia, Polycythemia vera, Sore throat, Nervousness, Rhinitis, Glossitis, Hypoesthesia
Cautions & Contraindications
Warnings & Precautions
Intensive treatment of vitamin B12-deficient megaloblastic anemia can lower potassium levels enough to cause sudden death. It should be used cautiously in patients with Leber's hereditary optic neuropathy. Thrombocytosis (a rise in platelet count) may also occur when severe vitamin B12 megaloblastic anemia is treated.
Contraindications
Leber's disease and tobacco amblyopia.