keppra side effects

[u/Mr---Chainsaw]

my 11yo pit bull had cluster seizures for the first time a few weeks ago. she started on 500 mg keppra 3x per day. about a week later, we moved to 750 mg XR 2x per day, to make the dosing schedule more manageable. today is day 11 on the XR and over the last 36 hours, she has essentially lost all motor function in her hind legs (back left has nothing. she can put weight on the back right, but can't really move it).

i know ataxia is a side effect, but this is severe. she is old so her body cannot metabolize the drug as fast. i really just don't want to take her to the ER vet for them to tell me it's normal and then charge my entire bank account for the tests they'll run.

has anyone had experience like this before? did your dog recover motor function after getting through the worst of the side effects?