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