Never Underestimate the Dangers of Chocolate

While for people it is a delicious treat, chocolate can be lethal to dogs. It is particularly theobromine, a naturally occurring substance found in chocolate, that is toxic to dogs. Like caffeine, theobromine belongs to a class of chemicals called mehylxanthines. Dogs simply cannot metabolize and excrete methylxanthines as efficiently as humans can therefore, while we can safely indulge ourselves with this sweet treat, for dogs chocolate is simply a sweet and deadly poison.

Various dogs react differently to chocolate. Theobromine can trigger epileptic seizures and can be especially dangerous to dogs that have epilepsy. It can also cause cardiac irregularity, especially if the dog becomes excited. Cardiac arrhythmia can precipitate a myocardial infract and this can kill the dog. Theobromine in chocolate can also irritate the GI tract and in some dogs cause internal bleeding which in some cases can kill the dog within a day or two. The symptoms of chocolate poisoning in dogs include vomiting, hyperactivity, restlessness, excessive urination, hypersensitivity to touch (the dog will jump when touched), very rapid heartbeat and breathing, loss of control of leg muscles, muscle tremors, seizures, general weakness, and coma.

The toxic amount of theobromine is approximately 100-150mg per 1kg of dog's weight (1kg=2.2pounds). However, different types of chocolate contain different levels of theobromine making some types of chocolate more poisonous in smaller amounts. Dark chocolate contains 450mg of theobromine per ounce of chocolate, bitter or baking chocolate or cocoa powder varies from 150mg/oz to as much as 600mg/oz, semi-sweet chocolate contains approximately 150mg/oz, and milk chocolate contains approximately 44-66mg/oz. As an example, the lethal dose for a 50lb dog such as a dalmatian, bulldog, or a standard poodle, would be approximately 50oz of milk chocolate, or 15oz of semi-sweet chocolate, or 5oz of baking chocolate.

So what happens when Rover does eat a bit of chocolate? As mentioned above, dogs are very inefficient excreting methylaxanthines. The half-life (or the time required for half the quantity of the ingested substance to be metabolized) of theobromine in dogs is close to 18 hours compared to only 2 to 3 hours in humans. When a dog ingests chocolate, the theobromines are absorbed by the intestines and taken to the liver through the portal vein. The liver removes some of the compound, but a significant quantity of it exits the liver through the hepatic vein. The hepatic vein carries the compounds to the inferior vena cava which dumps blood directly into the right side of the heart. After the blood is pumped through the pulmonary circulation, the theobromine rich blood returns to the left side of the heart to be distributed to the entire body. When the liver excretes the theobromine by products into the bile duct (which empties into the small intestine), the by products are converted back into theobromines which are then reabsorbed by the intestine and the entire cycle begins all over again. Each cycle results in the removal of only a very small quantity of the toxic theobromine compounds.

If your dog should accidentally happen to eat some chocolate, make a note of the amount eaten and how long ago, and contact your veterinarian immediately. Early medical intervention may save your dog's life and unfortunately there is not much you can do at home for your dog. If your dog ingested the chocolate less than 2 hours ago, you can induce vomiting while someone else is calling the veterinarian. This will reduce the amount of chocolate ingested giving your dog better chances of survival. To induce vomiting trickle one teaspoon of hydrogen peroxide for each ten pounds of body weight into the mouth. Never induce vomiting if the dog is comatose, not fully conscious, or has lost the gag reflex. Waiting to see what happens instead of taking the dog to the vet immediately can prove to be a fatal mistake. Never underestimate the dangers of chocolate.

The risk of chocolate poisoning is especially high during the holiday seasons of Easter, Christmas, and Holloween when large amounts of chocolate can be found in the house. You should always ensure that bowls containing chocolates are well out of the reach of your dog and that everyone in the house, including any guests or visitors and especially children, are well aware not to give any chocolates to your dog. Some people feel that it is ok to give small amounts of chocolate to their dogs, as they do not see any visible ill effects. The problem with this is that they are encouraging the dog to eat chocolate and are developing the dog's taste for it. Once a dog likes the taste of chocolate he will be a lot more likely to search for it in the house while he is left unsupervised. Dogs have an excellent sense of smell and it is more likely than not that the dog will eventually succeed in finding the place where you keep all of your chocolate supplies. Your dog will be in a sense unknowingly committing suicide by chocolate. You and your family may find yourself coming home to a horribly sick dog, as was the case in Daisy's story.

Author - Marta Wajngarten