Important as a diagnostic test and a therapeutic agent
Cobalamin (Vitamin B-12) is a water-soluble, cobalt-containing vitamin that plays an important role in a number of biochemical processes. Dietary cobalamin is acquired from meat and milk sources. Pancreatic enzymes are required for the series of steps in the intestine needed for absorption of this important vitamin and the active form is created and stored in the liver. The cat’s unique metabolism makes it particularly susceptible to cobalamin deficiency. Serum concentration of this vitamin when used along with other tests is useful for localizing disease.

In addition to its diagnostic value, deficiency of cobalamin has been associated with clinical signs.  Most commonly, low cobalamin levels correlate with inflammation of the distal small intestine. Deficiency of cobalamin decreases the function of intestinal cells which decreases the absorption of the vitamin. This vicious cycle leads to a worsening of the disease. Recent evidence from studies have shown that supplementation of cobalamin has been beneficial for patients with chronic gastrointestinal disease, pancreatic disease and liver disease. Patients who receive supplementation frequently gain weight, and have a decrease in such clinical signs as vomiting and diarrhea. Cobalamin levels are used along with other diagnostic tests to identify gastrointestinal disease. It is a non-invasive test that can help direct additional diagnostics and treatment protocols. If low levels are found, this confirms the presence of disease, and supplementation is required.

THERAPEUTIC DOSING AND ROUTE
At The Cat Clinic of Stillwater, we recommend cobalamin supplementation be administered at home by subcutaneous (under the skin) injection. Cobalamin is non-irritating, inexpensive, and a single bottle may last over a year. The dose recommended for cats is 250 µg or .25 ml of common generic preparations. Most generic cobalamin preparations are 1mg/ml, i.e. 1000µg/ml. (Note: because multi-vitamin and B complex injectable formulations contain much lower concentrations of cobalamin, and often cause pain at the injection site, their use is not recommended.)

The dose regimen is typically one dose weekly for six weeks, one dose every two weeks for six weeks, then dose monthly. Most patients are treated for at least 12 months, and many will require life-long therapy. To determine if therapy can be stopped, serum cobalamin concentrations are measured one month after last administration.

 Information from the web site of the GI lab www.cvm.tamu.edu