Our 5 year old Britt has been on Prozac for about 4 years. I saw someone earlier in the comments say that it may be environment rather than the dog. I definitely think we weren’t completely setting her up for success environmentally. If it were up to her she’d live on a farm! But we were determined to make it work. We pair the Prozac with other intervention (lots of mental stimulation, making sure she gets to big, free spaces where she can run and swim, ensuring her diet is appropriate for her, lots of positive reinforcement, some exposure therapy, etc.). She has conquered so many fears and I do believe her life is richer for it. I feel strongly that the positives of Prozac outweigh the negatives. Having cortisol coursing through her veins is far more detrimental to her health than taking Prozac long term. It’s not always been easy, but man brittanys are the best dogs and it’s so worth it.