Clearly what I am to discuss here this evening is hardly a question to a vet, since I'm providing the answer for that not asked.  But I would like to attempt a discussion and dissemination of what I believe to be some very important information.

Many of you have heard of an ingredient in most of today's sugar free gums called xylitol.  It is safe, it reduces bacterial counts of the mouth, and it is beneficial to diabetics...for HUMANS that is!  It's popularity has grown to the point that people are now baking with it.  However it is very slow to get out to the general public that this ingredient is deadly poisonous to dogs.  Let me explain:

Xylitol is poisonous to dogs, but almost indirectly.  It isn't a poison in and of itself, but rather it acts as a massive dose of sugar to a dog's system, triggering a massive release of natural insulin.  Of course xylitol is more an alcohol than a sugar, but either way, it is NOT sugar.  So this massive dose of insulin does it's thing and drives blood glucose into the cells of the body, dropping the blood sugar precipitously.  Anyone that has heard of or witnessed "insulin shock" knows how deadly this can be.  The symptoms start with ataxia, or a drunken gait/walk, progress to seizures, and then a coma ensues.  If a dog survives this part, liver failure may set in within the next week or so and cause the pet's demise.

So why am I bringing this up?  Well it happened to my own dog, Lenox.  Lenox is not your average dog.  She is a 95 lb female Bernese Mountain Dog, and has severe separation anxiety issues.  The night of her intoxication we had left to eat out at a local restaurant at 7PM.  We returned at 8:15PM.  I let the dogs out for a walk upon my return, and my wife came outside within a couple of minutes yelling that "the stupid dog" got on the table again and ate my 16 year old daughter's pack of gum.  She asked if that was going to hurt the dog.  I told her only if it has xylitol in it.  A few minutes later they came outside with a shred of the gum package, and sure enough, it had xylitol in it.  So I got on the Internet real quick just to determine how toxic it was and what was the lethal dose.  I hit a few veterinary password protected websites for some in depth information and speed read everything I could find.  I ran upstairs and got the hydrogen peroxide bottle and started pouring it down her throat until she vomitted.  this was about 8:35PM.  She brought up a lot of wrappers, some gum, and a strong "grape" smell.  I decided to watch her close to see how things would or would not progress.  By 9:30PM Lenox was staggering and walking like she was drunk and could not navigate stairs that she normally takes 3 and 4 at a time.  Melinda, my wife, and I raced her down to the clinic.  Her blood sugar was still 89...not dangerous.  I wanted to keep an eye on her, so we grabbed every supply we might need to treat her at home if she deteriorated.  By 5:30 AM she couldn't walk, but she was very depressed, stuporous, but her blood sugar was only 83.  So I brought her to work with me and we treated her with IV fluids, intravenous steroids (helps the patient to be more insulin resistant and helps bring the blood sugar up and it also helps stabilize cell membranes), and intravenous dextrose (sugar).  She was much improved 36 hours later and came home, still a bit wobbly.  It was probably 3 or 4 more days before her recovery seemed 100%.

Conclusions I have drawn:  The symptoms and side effects of this toxicity are clearly not just from the massive insulin release as Lenox had neurologic symptoms far more serious than would be expected with a blood glucose of 83.  Clearlly the xylitol is toxic to the neurologic system.  What is unknown:  1)  Lenox was on Metronidazole, an antibiotic used for the treatment of diarrhea.  In an overdose situation this antibiotic is known to have neurologic side effects.  Alcohols can often increase the absorption of many substances in the gastrointestinal tract.  Could xylitol have increased the expected absorption rate of the metronidazole and caused some of the extreme side effects?  2)  Lenox has been on Clomipramine twice a day for 3 years for the control and treatment of severe separation anxiety (the reason she got the gum off the middle of the dining room table right after we left the house in the first place).  This drug also has effects on the neurologic system and we don't believe any overdose symptoms would mimic what Lenox experienced, but we also don't know how clomipramine and xylitol might interact with each other.  My belief is the xylitol, consumed very shortly after she was given the metronidazole, increased the absorption of the metronidazole and likely caused a lot of her neuologic symptoms.  If this is not the case, then it is my belief that the xylitol is far more poisonous than at first we (as veterinarians) believed.

To summarize:  Xylitol IS poisonous to dogs.  It causes a precipitous decrease in blood sugar and can lead to ataxia, seizures, coma, liver failure, and death.  The lethal dose to a dog is ONE STICK OF XYLITOL SWEETENED GUM PER 14 LBS OF BODY WEIGHT!!!  Lenox ate 15 sticks of gum, or about 2.5 times the lethal dose.

I hope this sheds some light on a subject most of the readers here have never heard about, but I felt you need know as we go into the Holiday season and many of you may have artificially sweetened goodies around the house.

Sincerely,

Dr. Lloyd