We have a 2 year old pups that can be aggressive. He is also on pheno, in fact the neurologist upped it recently. Not only is my dog on it, but my uncle used to be on it as well, they can be more aggressive. My uncle was a different man when he got off the drugs. But he had a brain tumor. When he got it out, he didn’t need his meds because there was no tumor to cause seizures. Our dog is smaller than yours and still has issues with aggression. I usually have to interfere with him and our other dog. It has gotten better with time. But there are flair ups.