Why don’t more people suggest medicating your dog’s aggression?

Yesterday we returned a dog we had for 2 weeks. He lunged at 4 different people and probably would have bit them if it weren’t for the muzzle and bit me 2 days ago. We’ve talked to trainers and a behaviorist (the behaviorist certified through an org on the wiki here) and basically was alluded to how important exercise is, but unfortunately the dog is heartworm positive which is imperative he has 0 exercise or strenuous activity for 3-6 months. It felt like an impossible situation cause we own a cat and small dog. I felt less worried about his prey drive from what I’ve seen about people learning to manage and redirect that, each person we spoke to said all his behaviors were fixable, trainable, etc.. even tho he was fine with the dog, we were told he could redirect his energy to the other dog.

Yesterday we also had a vet appointment with a different vet than we saw last week. We were getting radiographs of his atrophied shoulder so we could know and pass on additional health information and if it’s a problem, etc.. the vet learned we were immediately taking him back to the shelter afterwards and told us to just keep him medically sedated while he is on his heartworm treatment to manage his behavior. At first it sounded crazy, medically sedating a dog for 3-6 months? It sounded unfair to the dog, but when I got home I did some googling and found Prozac can actually help dog’s aggression. Each trainer said he had fear based aggression, I feel like lowering his fear levels could help? We were also looking back and he has was gabapentin the first week we had him. We see gabapentin can also be an anti-anxiety and make dogs less anxious. I think he was on gabapentin when we saw him and the first week which is why he was more social and friendly. We had a friend who went to the pound with us come over 3 days after we adopted him when he was still on gabapentin and everything was fine and he was cuddling them, but when he was off and another friend came over he attempted to lunge at them.

So now I’m wondering if we didn’t actually explore more options and slightly frustrated no trainer mentioned anything about medication. The first vet we saw only gave us trazodone which is situational, but what about for daily life?