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29 March 2016

How Much Vitamin D Is Toxic to Dogs.

It sometimes happens that a dog swallows a number of Vitamin D or D3 capsules or tablets, but how poisonous or dangerous is this, are there treatments available? What is the toxic dose of Vitamin D in the dog? At what point should you take your dog to the ER vet. What are the symptoms of Vitamin D toxicity in the dog and how is Vitamin D poisoning in the dog treated?


This is, in fact, a toxicity which I dealt with quite a few times in the past at my clinic. Most of these cases involved dogs getting hold of vitamin supplements which the owner had left lying about the house. Flavoured ones are particularly attractive to dogs and hence more dangerous, however, vitamin D toxicity can also occur where dogs have access to rodent poisons.

1. But how much vitamin D is toxic to dogs? When should you rush your dog to the ER vet and when is it safe just to observe your dog? Well, opinion varies depending on where you look up the information and the toxic dose may also vary with individual cases, but taking a very careful and conservative approach I personally usually only start to become concerned at dose rates higher than 0.1 mg per kg of the dog's body weight. { There are 40,000 iu per mg of vitamin D }

Lets express the above in a easier to understand way. Basically, you will start to be concerned when a dog takes more than 4,000 iu per kilogram of bodyweight which works out as 1,811 iu per pound of bodyweight. iu = international units and the number of iu units per tablet or capsule in your case should be clearly stated on the bottle or packaging.

To be fair most cases of vitamin D toxicity that I have dealt with involved much greater amounts than those I have listed above, but in my experience a dog will be unlikely to suffer adverse reactions where lesser amounts than those have I stated were swallowed.

2. What are the symptoms of vitamin D toxicity? Vitamin D is potentially toxic to dogs because it is linked with the metabolism of calcium in the body. Too much vitamin D causes too much calcium (hypercalcemia), and that is what causes the damage, this could include kidney failure, haemorrhage, and tissue mineralization in the heart, liver and kidneys.

Where your dog is in an acute overdose situation you might expect to see symptoms start some 12 - 48 hours after ingestion, and these could include vomiting, dark diarrhoea containing blood, lethargy, inappetance and drooling in the early stages. Later symptoms could include marked weight loss and seizures. Fatalities are possible where very large amounts have been ingested.

3. What to do if you suspect your dog has taken an overdose? As with a great many toxins if you can induce vomiting to recover the drug within the first hour after ingestion { Two hours at the very outside } then this should greatly help. 

Please follow this link for an accurate article which covers the best way to quickly induce vomiting in dogs: LINK

However, if you suspect your dog took a toxic amount of Vitamin D and you fail to quickly and thoroughly induce vomiting then you will need to get a vet involved ASAP as supportive care such as IV fluids may be necessary and some dogs may require a blood transfusion. There are also drugs which can be used to prevent further absorption of the ingested vitamin D if given early enough. So clearly time would be of the essence so use an ER vet if necessary.

I hope you have found this article of interest.


Dr Scott