Need advice for teenage dog

I’m looking for advice and especially experiences with starting medication for dogs with anxiety/arousal issues.

I have an 11-month-old intact male Rottweiler. I got him at 8 weeks old, and he has been a handful from day one. He has always been extremely mouthy. I put him in puppy classes starting at 10 weeks, and even the trainer commented on how unusually mouthy he was. Multiple vets and trainers reassured me that it was normal puppy biting and that it would improve after teething—but unfortunately, it’s only gotten worse.

From puppyhood, he seemed unable to settle. If he wasn’t eating or asleep, he was constantly panting. We ruled out medical causes and started working on “place” and “settle,” but he’ll only do those behaviors for treats. Once the food is gone, he’s immediately back to pacing, chewing, licking, or getting into trouble.

We’ve tried:

– Plenty of physical exercise and mental stimulation

– Place/settle training

– Tethering (he chewed through leashes, then the cot itself)

– Bully sticks and long-lasting chews

The only time he truly relaxes is when he’s actively chewing something like a bully stick. Once it’s gone, he immediately starts chewing inappropriate things (couch, leash, me) or obsessively licking me for long periods of time. If I let the licking continue, it can go on for hours. Eventually I have to crate him just so everyone can calm down. At this point, he’s crated unless he’s chewing something appropriate, which feels awful but otherwise he’s destructive or biting.

Over the last few months, leash reactivity has also become an issue. A few months ago, an off-leash dog ran up to him in our apartment complex. Before that, he was mostly neutral to dogs on leash. Since then, he lunges and barks when he sees other dogs. We’re working with in-home trainers and group classes, but living in an apartment complex makes management extremely hard—there are corners, entrances, and blind spots everywhere, so avoiding triggers is nearly impossible.

The most concerning issue is his arousal biting. Once teething ended, he started biting the leash or redirecting onto us—lunging and biting arms when he’s overstimulated, excited, or frustrated. It usually happens after pooping, running around in an open field, or on walks. This isn’t nipping. He’s nearly 100 lbs now and bites HARD. We’re left with bruises, and sometimes he breaks skin. I truly don’t think this is aggression—he’s otherwise a very sweet dog—but the behavior is dangerous and escalating.

Things we’ve tried for the arousal biting:

– Not reacting (very hard when it hurts this much)

– Tossing treats to redirect (he eats them, then immediately bites again)

– Tethering him to a pole or object so he can calm down (not always possible, especially outside)

Sometimes I’m being actively bitten while trying to get enough distance just to escape. He’s been through a board-and-train program, but it didn’t make a meaningful difference. Right now, we are muzzle training for safety but I still have to walk him on leash for potty breaks, so complete avoidance isn’t possible.

At this point, I’m wondering if this is primarily an anxiety or arousal regulation issue and whether medication could help him reach a baseline where training can actually stick. It feels like he’s constantly living in a state of over-arousal and simply can’t self-regulate, no matter how much training or structure we provide.

If anyone has experience starting medication or has had a dog with severe mouthiness or arousal biting that improved over time, I would really appreciate hearing your story. I’m also open to insight on whether this sounds anxiety-based or something you’ve seen before. I have considered neutering him but have heard that can make reactivity worse. There’s only one vet behaviorist near us and we currently have an appointment for April but I need help sooner so I was thinking about consulting our regular vet tomorrow.

I truly love this dog and am doing everything I can to help him succeed, but we’re running out of safe options and I want to make sure I’m doing right by him.