Loss of appetite with Cimalgex?

Cosette, our 17-year old Poodle mix, has been taking Rimadyl (25 mg, anti-inflammatory) and Gabapentin (100 mg, to block pain) daily for the past 6 months. Our vet in the US had recommended the Gabapentin even with no epilepsy, and it seemed to help. Last week, our French vet was concerned by low white blood cell reading and recommended Cimalgex (30 mg), in case Gabapentin was a factor. After four days on Cimalgex the dog seems to be off her food and this morning refused her post-walk treat. Don't know if she is constipated, or if it's from lack of food or the extreme cold, but I've not used a poop bag since Tuesday evening (over 36 hours). The literature suggests Cimalgex is well tolerated by most dogs, but Cosette is not acting like herself, and seems a bit twitchy and lethargic in her movements. Could Cimalgex be the culprit here? Or does this sound more like a coincidence?

It could be either, but you really need to get back to the vets urgently!

At 17 years old, don't take any chances. The vet is your friend if you let them be and they are the best placed to deal with medical conditions.

Thanks for your kind reply. We stopped the pill for today and tomorrow, and are scheduled to see the vet in the morning. Dog seems a bit more like herself, and I think visit will be more productive if we can be clear and precise in describing what we observe. Thanks again!