Cholecalciferol is thechemical name for Vitamin D3, and is commonly found in manyhousehold products. Sources of Vitamin D3 – or even the less potentform D2 – include the following:
Despite having the“vitamin” in its name, cholecalciferol can be quite toxic when accidentally ingestedby dogs and cats. When ingested, it causes the body to absorb too much calciumfrom the gastrointestinal tract, bone, and kidneys. This results inlife-threatening high calcium (“hypercalcemia”) and phosphorous(“hyperphosphatemia”) levels in the body; this can cause secondary boneychanges (“mineralization”) to the tissues of the body. Organs such as thekidneys, intestines, aorta, and heart can be affected. When mineralizationoccurs, it can result in severe acute kidney injury (AKI) within a few days.
Cholecalciferol comes in variousconcentrations and strength. With multivitamins, Vitamin D3typically has a wider margin of safety. Most vitamins contain a large range of VitaminD3 per tablet (ranging from 400 IU to 5000 IU). One IU of vitamin D3 is the equivalentof 0.025 mcg or 0.000025 mg of Vitamin D3.
More dangerous sources of cholecalciferol include mouse and rat poison (commonly under the brandname Tomcat, Terad3, Quintox, etc.). Unfortunately, these mouse and rat poisonshave a very narrow margin of safety,meaning it only takes a small amount to result in severe poisoning andsecondary AKI. In fact, with certain brands, it only takes as little as 1 ounce(one block) of mouse and rat poison to result in potential kidney failure in a 70-80pound dog. In dogs, the lethal mouse and rat poison dose that kills 50% ofpatients that get into it (commonly called the LD50)is only 85 mg/kg (based on the concentration of 0.075%). Toxic doses of VitaminD3 are considered to be as low as 0.1 mg/kg of body weight.
Breeds predisposed While no specific breed of dog is predisposed, accidental poisonings are more commonly seen in puppies or younger dogs. That’s because younger dogs may not be crate trained as well, or may be more curious in nature. Cats are also more sensitive to cholecalciferol.
Clinical signs Clinical signs of Vitamin D3 poisoning often don’t develop for 1-3 days until kidney failure has already taken place. Signs include:
Diagnostics Your veterinarian will need to do several tests when it comes to cholecalciferol poisoning, including:
Treatment Treatment must be initiated with cholecalciferol poisoning, due to the narrow margin of safety. Treatment includes:
Treatment of cholecalciferol poisoning used to be very expensive, as hospitalization used to be recommended for 2-7 days (or until the calcium levels return to normal). Another added expense is the frequent blood work monitoring (e.g., specifically for kidney function, calcium, and phosphorous) every 12-24 hours while hospitalized, and then every 2-3 days thereafter for the next 2-4 weeks once discharged. However, recent recommendations from the ASPCA Animal Poison Control Center found that hospitalization may now be reduced with aggressive decontamination and monitoring instead.
Prevention The best way to avoid this deadly poisoning is to make sure your house is appropriately pet-proof. Crate training your puppy early in his or her life is the safest way to prevent accidental poisonings. Keeping OTC and prescription medications out of reach (e.g., high up on a closed shelf) is key. Avoid the use of any type of mouse and rat poison in your house, garage or yard; instead, consider more humane and environmentally friendly snap traps instead.
Even with aggressive treatment, cholecalciferol poisoning can have long-lasting affects and result in secondary chronic renal (e.g., kidney) failure (CRF). This can dramatically shorten the lifespan of the pet. As with most poisoning cases, the longer you wait, the most expensive it is to treat and the worst prognosis for your dog or cat. When in doubt, if you suspect your dog or cat got into cholecalciferol, seek veterinary attention immediately or contact the ASPCA Animal Poison Control Center for life-saving advice. #ad
What are the signs of vitamin D poisoning?
Signs of vitamin D poisoning typically start 12-36 hours after ingestion. The severity of signs depends upon the amount of Vitamin D ingested. Vomiting, diarrhea, increased drinking and urination, abdominal pain, depression, and lack of appetite are generally seen with smaller doses. Higher doses can cause elevated levels of calcium and phosphorous in the body which may result in kidney failure. In addition to the signs above, severe poisoning may also cause an increased respiratory rate, difficulty breathing, bleeding in the intestines, slow heart rate, abnormal heart rhythms, and mineralization of body tissues. Without appropriate treatment, death may occur.
What is vitamin D poisoning?
Vitamin D is necessary for the body to absorb calcium, a mineral that is essential for healthy bones, muscle movement, nervous system function, and immune system function. Excessive amounts of Vitamin D may result in poisoning. There are two forms of vitamin D. Plants, fungi, and yeasts produce Vitamin D2 (ergocalciferol) and Vitamin D3 (cholecalciferol) is produced by animals.
Poisoning commonly occurs when pets ingest rodenticides (rat and mouse poisons) containing cholecalciferol or supplements containing either form of Vitamin D. Vitamin D2 (ergocalciferol) has a much wider margin of safety than vitamin D3 (cholecalciferol) and larger amounts are generally more tolerated by animals. Many topical psoriasis medications also contain potent amounts of vitamin D (i.e., calcipotriene, tacalcitol, or calcitriol) and poisoning can occur when pets lick the cream off someone’s skin or directly from the tube of product. Improperly formulated pet foods, both commercially produced and homemade, have also resulted in poisoning.
How is vitamin D poisoning diagnosed?
Most cases of vitamin D poisoning are diagnosed in pets that have the expected signs and a known or suspected exposure to Vitamin D-containing supplements, rat/mouse poisons, or psoriasis treatments. Blood work showing elevated levels of calcium, phosphorous, or markers of kidney damage increase the suspicion for vitamin D poisoning. A urine sample may be performed to help assess kidney function. In some cases, specialized testing to rule out other causes of elevated calcium may be necessary.
FAQ
How much vitamin D is toxic to a dog?
It can take as little as a dose of 0.1 mg/kg to cause vitamin D poisoning. That’s about 0.45 mg per 10 pounds of body weight. The fatal dose is around 2 mg/kg, which equals about 9 mg in a 10-pound dog.
Can vitamin D make dogs sick?