Protect from light.
Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit.
Hydroxocobalamin injection should be given only intramuscularly.
In patients with Addisonian Pernicious Anemia, parenteral therapy with vitamin B12 is the recommended method of treatment and will be required for the remainder of the patient’s life. Oral therapy is not dependable. In other patients with vitamin B12 deficiency, the duration of therapy and route of administration will depend upon the cause and whether or not it is reversible.
Confirmatory diagnostic studies should be performed prior to initiating therapy, if possible, and the patient should be followed with appropriate studies to demonstrate hematologic improvement (Hgb, hematocrit, RBC, reticulocyte count). A diagnostic trial utilizing physiologic doses of vitamin B12 (1 mcg daily) and observing daily reticulocyte counts after establishing a baseline may also be performed. The observation of reticulocytosis which usually occurs between the third and tenth day of therapy confirms the diagnosis of vitamin B12 deficiency.
In seriously ill patients it may be advisable to administer both vitamin B12 and folic acid while awaiting the results of distinguishing laboratory studies. It is not necessary to withhold vitamin B12 therapy until the precise cause of B12 deficiency is established since absorption studies can be performed at any time.
Serum potassium should be closely observed the first 48 hours and potassium should be administered if necessary.
Treatment of Vitamin B12 Deficiency
Thirty mcg daily for 5 to 10 days followed by 100 to 200 mcg monthly injected intramuscularly. If the patient is critically ill, or has neurologic disease, an infectious disease or hyperthyroidism, considerably higher doses may be indicated. However, current data indicate that the optimum obtainable neurologic response may be expected with a dosage of vitamin B12 sufficient to produce good hematologic response. Children may be given a total of 1 to 5 mg over a period of 2 or more weeks in doses of 100 mcg, then 30 to 50 mcg every 4 weeks for maintenance.
Patients who have normal intestinal absorption may be treated with an oral therapeutic multivitamin preparation, containing 15 mcg vitamin B12 daily.
Schilling Test
The flushing dose is 1000 mcg.