This preparation is indicated in Pernicious anemia,Vitamin B12 deficiency due to low intake from food,Thyrotoxicosis, Hemorrhage, Malignancy, Liver or kidney disease,Gastric bypass surgery, Total or partial gastrectomy, Gluten enteropathy or sprue, Folic acid deficiency, Macrocytic anaemia
Vitamin B12 (cyanocobalamin) is required for the maintenance of normal erthropoiesis, nucleprotein and myelin synthesis, cell reproduction and normal growth; Coenzyme; metabolic functions include protein synthesis and carbohydrate metabolism. Plays role in cell replication and hematopoiesis.
Usual Adult Dose for Pernicious Anemia
Initial dose: 1000 mcg intramuscularly or deep subcutaneous once a day for 6 to 7 days
If clinical improvement and reticulocyte response is seen from the above dosing:
- 100 mcg every other day for 7 doses, then
- 100 mcg every 3 to 4 days for 2 to 3 weeks, then
- Maintenance dose: 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
Absorption reduced by antibiotics, aminosalicylic acid, anticonvulsants, biguanides, cholestyramine, cimetidine, colchicine, K salts, methyldopa.
Leber’s disease, tobacco amblyopia.
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
Pregnancy Category A. Adequate and well-controlled human studies have failed to demonstrate a risk to the fetus in the first trimester of pregnancy (and there is no evidence of risk in later trimesters).
Lactation: Drug distributed in milk.
Intensive treatment of B12-deficient megaloblastic anemia may cause hypokalemia and sudden death. Use with caution in patients with Leber optic nerve atrophy. Thrombocytosis may occur with treatment of severe vitamin B12 megaloblastic anemia