I use ACP regularly on horses (did you mean ACP as you've put APC in the title?) and never experienced an adverse effect, the tablets we had were 25mg and for small animal use but that is a large dose. For example a shetland pony that weighs around 150-200kg would be given 3-5 tablets depending on their temperament. We now have 10mg tabs as our vets said they can no longer get it in 25mg
. The feral yard cat had to go to the vets and she was given 1/4 of a 25mg tablet and was completely out of it. With the horses it can have the desired effect of 'taking the edge off' and are then relaxed in a situation where they would normally not be, but some can still be fighting the situation and the sedative which makes them clumsy and unpredictable
. I wouldn't give it to my dog unless it was an extreme situation and not without discussing it thoroughly with a vet I trusted, which TBH doesn't sound like yours
. Again if it was my dog having vaccinations would be a lower priority than the behaviour issues and I would be looking at finding another vet and working on her training (which is what I have done although Millie's problems were no where near as bad as yours sound
).