Expert: Jennifer Fry - 9/23/2004

Question
Hi, Dr. Fry.  My question is:  
Is it possible that an overdose of Valium could lead to death?  My 100 lb, 9 y.o. rottie was prescribed 100 mg of Valium by an emergency clinic this past weekend, and it was my gut feeling that the doseage was too high, but I figured they knew what they were doing, so I didn't question it.  (My 40lb foxhound takes 40mg before a sever thunderstorm.....I figured that on a per lb basis, that would have been almost correct......)
Anyhow, my rottie died 3.5 hours after the administration of the valium.  Reason for the emer. clinic was:  she vomitted during the night, had diarrhea, and was panting heavily.... couldn't get up, and seemed painful to move or touch. Her abdomen seemed tender, but was not at all distended.  About 30 minutes after the valium administration, her rapid breathing and pulse slowed to very shallow.... she went completely catatonic, and finally stopped breathing all together.  Her only know medical problems were mobility issues, and she was on Deramax (PO), Adequan (IM), Cosequin (PO), and Winsterol (IM&PO)for that.  Otherwise, she was "strong as an ox" according to my vet.  
While I am not one to take legal action, I don't want to see this happen to anyone else's beloved pet!  I can't sleep at night, thinking that I let her down by not questioning the doseage.  Two vets have told me that it is impossible to die from a valium overdose, yet after doing some research, I know that a 200 lb human should only take between 5-20 mg, and while I know that animals are different, I can't help thinking that the valium is what did her in, and the vomitting and diarrhea could have been a reaction to the Deramaxx, which was increased by my vet 2 days prior to her death.  
Any thoughts or suggestions?  
I would appreciate anything you could give me. Most other vets I have consulted just shake thier heads, and can't..... or won't?.... give me an honest answer.  
Thank you so much for your time!
Warm Regards,
Kelly Psiuk

Answer
HI KELLY

To me that dose seem like a high dose; however, since your dog was sick to begin with, she may have died anyway with or without intervention? I can't say for sure.  I do not know what the lethal dose of valium is off the top of my head.  A normal/average dose that I would give to start is 0.5 mg per kg, which is about 4-5 X LESS than what she was given.  Obviously IV administration of valium is more potent than oral administration.  You can check for LD50 on the internet and see if you can find the lethal dose for a dog.  I don't have my formulary here at home with me to look it up.  Obviously any drug when given in excess can cause problems and certainly some drugs will lead to death if too much is given.  Valium will lead to cardiac depression as well as relax all other muscles.

I always get concerned about bloat in large breed dogs and this could have been a possibility too.  Maybe a stroke?  Yes the vomiting and diarrhea could have been from the Deramaxx as that is one of the common side effects....she could of had internal bleeding as well.  It is really difficult to say for sure.  Did you have an autopsy done on her?  That would help answer your questions as far as underlying problems.

take care and so sorry for your loss,
Dr. Fry