Chocolate toxicity

Q. Is the chocolate toxicity seen in dogs also seen in cats and humans ? If not -- why ?

A. Chocolate contains both caffeine and theobromine. Dogs and cats have an LD50 for both at a level of 100-200mg/kg. With adults (humans) caffeine deaths start at 18-50g (recently there was a college student who on a dare took 90 caffeine pills-18g-and died). Rats can handle up to 310mg/kg of theobromine before we start to see any deaths. Its all species related.

As for why we rarely see chocolate toxicity in cats, it's because they are much smarter than dogs:)

Tina Wismer, DVM

National Animal Poison Control

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How come people don't get sick as dogs binging on chocolate....

Q. Had an interesting question from client last night (whose dog ate 1/2 a box of chocolate truffles). Do people get theobromine toxicosis from chocolate binging? What's the LD50? Same as dogs? I guess an oz of dark chocolate/kg BW is alot but I'll bet there are people who eat close to this during the holidays. Just curious ...I'm not a big chocolate fan myself : )

A. People might get a buzz from chocolate, but one of the really big problems for dogs is that the half-life of theobromine is excessively long in dogs compared to a lot of other species. The half life in dogs is over 17 hrs. Also, the methyl xanthines are amphoteric, so you can't ion trap them out of the urine. Additionally, those compounds are recirculated via the enterohepatic pathway. So... treatment of chocolate in dogs, in addition to working with possible gi upset and pancreatitis from the other goodies, requires repeated doses of activated charcoal (Q 3-5 hrs for up to 72 hrs). It also helps to get them on high fluids and catheterize the bladder (methyl xanthines may be reabsorbed from the bladder wall too) to keep things flowing. For what its worth. Have a nice holiday.

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How much chocolate can dogs eat before getting sick?

Q. I did a literature search and found LD50 for chocolate posted as 250-500mg/kg and then as 100mg/kg. Big range. Which is it? The 250-500mg post went on to say 'this translates to 1 oz baking chocolate/kg BW or about 10-15 oz milk chocolate/25 lb dog. Am I doing my math wrong? Even with the lower LD50 of 100mg/kg : A 12 kg dog times 100 mg = 1200mg LD50. Baking chocolate is posted as 400mg/oz. Looks like 3 oz LD50 to me. Same for milk chocolate posted at 40mg/oz. A 12 kg dog would need to eat 30 ozs.

A. I think your calculations are pretty close. Remember the LD50 of course is not for the chocolate but for the theobromine and caffeine component in it. Milk choc has about 6 mg caffeine/oz and 44 mg theo/oz. Baking has about 35 mg caffeine/oz and about 392 theobromine/oz. The LD50 of caffeine and theo in dogs and cats is 100 to 200 mg/kg. As I see it that's about 2 oz of milk choc per kg for the LD50 and about 10% of that dose for the baking choc. Don't forget, that's just the LD50 - what about the other 50% who didn't die but just vomited or seizured for a few hours! I always feel that an exposure of 10 to 20 % of the LD50 is enough to take seriously in any possible toxicosis. This brings the consumption down considerably as far as what may cause clinical signs in these critters. Also remember that the half life of theobromine is 17.5 hrs so these guys can be affected for some time. In fact some texts reccomend catheterizing the bladder to prevent further reabsorbtion from the bladder wall (these methylxanthines are excreted whole). I could go for a thick bar of that Swiss stuff right now.

Happy holidays to ya,..Mark