Hi, I also used Prozac for my cat....he’s since passed away at 15 years old due to renal, not related to the medication that I’m aware of.
Nemo was on prozac also for inappropriate elimination
He was on Prozac for 4 years or more, I believe it took a few days to work so don’t give up yet. When he did stop his behaviour I began giving it only every second day...than every 3 rd...eventually I was able to go down to once per week. It’s something you’ll have to discuss with your Vet. Good luck
Should mention Nemo was a small cat weighing around 7 lbs. his Prozac was in liquid form and his dose was .7 cc/ml....note the point7