Flagyl and seizure

Question
I am new to this and I want to first say thanks for being here.

I have a mini long haired dachshund named Casey  http://www.waugh.ca/torontodachshund/images/photos/finnigan+casey/imag0005.jpg
. He is the best thing ever but was recently ill.

He had the runs and the vet gave him Flagyl to stop it. Everything worked out great for the first 24 hrs. It stopped the diarrhoea but he had a seizure within 24 hrs of taking the medication. We rushed him to the vet and asked her to look at him. She mentioned that it was very hard for her to believe that the medication caused it. I immediately took him off of the medication after one day. It has been 10 days now without a reoccurrence of a full blown seizure but yesterday he has developed a head tremor like syndrome.

My research in to the drug is that there are possible side effects if overdosed or used on puppies or kittens that are seizure like conditions.

I am desperate to find out if the seizures are related to the drugs or if it was an underlying condition. Has anyone else experienced this? Does it take days, weeks or months to weed this out of their system?

Any information at all would be greatly appreciated. It breaks my heart every time I think about this poor little guy and how the meds may have seriously or permanently damaged him.


Answer
There are possible neurological side effects with HIGH doses of Flagyl (greater than 30 mg per kg in cats and 50mg/kg in dogs), but I have only ever seen it happen in one cat several years ago and we use A LOT of flagyl.  

Half of the drug is eliminated from the body within 8 hours and after 48 hours there shouldn't be any left in the body.  And the tremors are more likely a result of the seizure and not the drug at this point.  During a seizure blood sugar and oxygen to the brain can become too low or body temp too high causing a bit of brain damage

The seizure MAY have been from the medication or coincendental as seizures can be due to low blood sugar, electrolyte abnormalities, low calcium, liver disease (especially liver shunts in puppies), kidney disease, and sometimes underactive thyroid.  What I would suggest is that you have a complete chemistry screen checked on your dog to rule out any blood abnormalities.  Is there any possibility he got into anything?  As chocolate and moldy food are 2 common things that can cause seizures too.

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