This blog post will walk you through: vitamin b12 overdose in cats. Don’t worry, we’ve got all the answers about this subject.
Overview Of Using Vitamin B12 For Dogs And Cats
Vitamin B12 (cyanocobalamin and hydroxocobalamin) is essential to growth, cell reproduction, hematopoesis, and nucleoprotein, myelin synthesis, and treating B12 deficiency for dogs and cats. It works in close concert with folate in the synthesis of the building blocks for DNA and RNA synthesis. It is also essential for the maintenance of the integrity of the nervous system and for the synthesis of molecules involved in fatty acid biosynthesis, amino acid metabolism, and the production of energy.
The cobalt-containing B12 molecule is the largest molecule to be transferred across the intestinal mucosa and transfer occurs only in the ileum. Free B12 then attaches to intrinsic factor (IF) to be transported across ileal cells as a dimer. It is then transported to the liver in the bloodstream bound to transcobalamin-2 (TC-2).
The liver is a rich repository for B12 and releases it, as needed into the systemic blood stream. Frank deficiency of B12 or gastric, intestinal, or pancreatic disorders that affect the absorption of B12 will lead to B12 deficiency. The most important reactions in the body in which B12 is involved are:
a) rearrangement of methylmalonyl-CoA to succinyl-CoA for use in gluconeogenesis b) transfer of a methyl group from N5-methyl tetrahydrofolate to homocysteine in the formation of methionine [under the influence of methlycobalamin synthase] with resultant formation of tetrahydrofolate.
Tetrahydrofolate is involved in purine, pyrimidine, and nucleic acid biosynthesis. A) rearrangement of methylmalonyl-CoA to succinyl-CoA for use in gluconeogenesis b) transfer of a methyl group from N5-methyl tetrahydrofolate to homocysteine in the formation of methionine [under the influence of methlycobalamin synthase] with resultant formation of tetrahydrofolate. Clinical signs of B12 deficiency include inappetance, lethargy, and failure to thrive.
Hematological signs include non-regenerative megaloblastic anemia, anisocytosis, poikilocytosis, and neutropenia with hypersegmentation, Biochemical signs of B12 deficiency include reduced serum cobalamin levels, increased serum methylmalonic acid levels, homocystinuria and methylmalonuria.
Brand Names And Other Names Of Vitamin B12
This vitamin is registered for use in humans. Precautions and Side Effects
Vitamin B12 is essentially non-toxic but it should not be given to animals with known hypersensitivity to it or to cobalt.
Drug Interactions
A number of drugs are known to affect the absorption of vitamin B12, including neomycin, potassium chloride, p-aminosalicylic acid, and colchicine. Dog:
By injection: 50 mcg/kg every 2 weeks (effective in one study)
Oral treatment of B12 deficiency is not always effective, depending on the cause. Intrinsic factor (IF) may have to be supplied to facilitate B12 absorption.
It can be dosed at 100 to 200 mcg/kg once daily.
Feline Vitamin Toxicity
Normal requirements differ for different vitamins and there are a variety of causes of vitamin toxicity, depending on the type of vitamin.
Vitamin A Toxicity In Cats
Excessive feeding of diets containing a large amount of liver
Inappropriate use of vitamin A-containing supplements, especially fish liver oils
Vitamin B-6 Toxicity in Cats
Oversupplementation of vitamin B-6
Vitamin C in Cats
Oversupplementation of vitamin C
Vitamin D Toxicity in Cats
Rodenticides (rat poison) containing cholecalciferol
Inappropriate use of vitamin D-containing supplements, especially fish liver oils
Ingestion of Cestrum diurnum, an ornamental house plant
What To Watch For
Clinical signs of vitamin toxicity depend on the vitamin, the amount ingested and the length of time the ingestion occurs.
In animals with vitamin A toxicity, watch for lethargy, anorexia, weight loss, limping (front legs), changes in sensitivity over the neck and forelimb region, stiffness and constipation. In animals with vitamin B-6 toxicity watch for changes in the nervous system (neurotoxicity) and sensitivity to light. Diagnostic Tests for Vitamin Toxicity in Cats
Diagnosis is based largely on signs of intoxication coupled with a history of ingestion or oversupplementation.
Complete blood count, biochemical profile and urinalysis are often recommended to determine overall health and organ effects. Radiographs (x-rays) of the neck, chest, ribs and joints, chest and abdomen, depending on which vitamin toxicity is suspected. Treatment of Vitamin Toxicity in Cats
Treatment is largely supportive and symptomatic and depends on the underlying vitamin toxicity.
Discontinue supplementation or ingestion of the vitamin. Activated charcoal may be administered to some patients early on to aid in additional gastrointestinal absorption and removal.