Proin side effects

I have a 9 yo husky/german shepherd 60lbs who just recently started having incontinence. She is peeing while just relaxing on the floor or when she sleeps. The vet prescribed proin. I gave it to my dog and a few hours in she was trying to puke, and then was panting like crazy and also had rapid breathing. I told the vet about this and she said to try another dose. I did not as that seems crazy to put the dog through that. What should I do? Thank you