Vitamin D Toxicity in Pets

The pet food brands made into the news lately. The excess nutrients found in the popular dog food brands recently stirred the debate on keeping a closer look at the pet food contents.

The report submitted by FDA (Food and Drug Administration) suggests that several popular brands of dog food have 70x the safe levels of Vitamin D which could kill dogs. Although it is rare, it is noteworthy to understand how it can adversely affect your pets.

Vitamin D Toxicity

Vitamin D toxicity is a buildup of excess calcium in your blood (hypercalcemia) which can cause various physical and mental ailments such as nausea, vomiting, weakness, or even kidney failure and death.

The homemade and raw meals lack Vitamin D, hence, most pet food brands added extra Vitamin D to compensate the homemade meal. At least 11 different labels or dog food brands were asked to recall their products by FDA.

Symptoms of Vitamin D Toxicity

  • Vomiting
  • Weakness
  • Depression
  • Loss of appetite
  • Increased thirst (polydipsia)
  • Increased urination (polyuria)
  • Dark tarry feces containing blood
  • Presence of blood in vomit
  • Loss of weight
  • Constipation
  • Seizures
  • Muscle tremor
  • Abdominal pain
  • Excessive drooling

Cholecalciferol & Vitamin D3

Cholecalciferol, also known as Vitamin D3 is a type of Vitamin D which is naturally produced by the skin when exposed to sunlight. It’s also found in some human and pet foods or is taken as a dietary supplement.

It is important for the absorption of calcium from the stomach and for the functioning of calcium in the entire body. Cholecalciferol is used as a treatment or to prevent health conditions caused by a lack of vitamin D, especially skin and bone conditions.

Exposure

Taking 60,000 international units (IU) a day of Vitamin D for a longer period of time has been shown to cause Vitamin toxicity.

Cholecalciferol based rodenticides

Anti-coagulant Rodenticides commonly consist of Cholecalciferol. Concentration is typically 0.075% or 750ppm which equates to about 23mg/ounce of rodenticide. The clinical signs of toxicity are noted at > 0.5mg/kg of cholecalciferol ingestion, therefore a 44-pound dog would need to eat less than 1/2 ounce to cause toxicity.

Vitamin D Supplements

The intake of Vitamin D supplement is common in most pet food brands. Pet owners choose to add Vitamin D to their regular meal to compensate for its lack of nutrients. Multivitamins contain a relatively small amount of Vitamin D, hence, toxicity from multivitamin ingestion is rare. Primary Vitamin D supplements contain a large amount of cholecalciferol which raises the concern of toxicity.

Vitamin D Analogs

There are multiple Vitamin D analogs approved for use in humans which is included in psoriasis creams used for the treatment of secondary hyperparathyroidism, doxercalciferol, or Hectoral which is used for the reduction of pTH (Parathyroid hormone). Dogs tend to lick the skin where the cream is being applied. The routinely licking of skin can cause toxicity.

Pet Food Contamination

Several commercially available pet foods have been known to contain Vitamin D as the major nutrient content. The over-supplementation of Vitamin D can lead to toxicity.

Treatment

Decontamination is the major treatment for Vitamin D toxicity. Within the last 4-6 hours of ingestion, vomiting should be induced with apomorphine at 0.03-0.04mg/kg IV. Hydrogen peroxide can be administered at a dose of 2.2ml/kg, with a maximum of 45ml, repeated once.

Hydrogen peroxide should be avoided in the case of cats as they are more susceptible to adverse effects. In cats, vomiting can be attempted with either xylazine at 0.44mg/kg IM or dexmedetomidine at 10mcg/kg IM.