That could very possible be it:
Potential Baytril Medication Side Effects and Drug Interactions
As with most pet medication, there are some possible side effects with baytril. In dogs, rare, but potential side effects include, but are not limited to, gastrointestinal issues such as diarrhea or vomiting, elevated liver enzymes, seizures, depression and nervousness are also possible.
http://www.discountpetmedicines.com/...antibiotic.htm
I hope he gets back to normal soon.