Tegretrol: "The side effects have often been brutal. I forgot to mention severe akathisia that was torture-like, in 2009, when I used high doses of Seroquel without Atarax or Gabapentin - atenolol did not work well to ameliorate the akathisia. In 2017 I tried again, this time with Gabapentin or Atarax, and both worked, and it seemed like a miracle, but then I was hit with QT-prolongation."

Atenolol is a beta blocker, true, but it's heart specific. It works on my extra heartbeat (PVC), for example, but not for my akathisia. For that you need a systemic beta blocker like propranolol. Antihistamines (Atarax) can help akathisia, but are not very strong for that. A few studies have shown that gabapentin can work but it's definitely not first line.

Another drug you mentioned having a rash with and said that Benedryl didn't help. It seems obvious, but you didn't say. Did you try a cortisone cream with that? [I was concerned myself that cortisone is a steroid but I've never had a problem with topical cortisone. Maybe not related to prednisone?]

Saphris is not considered a heavy weight gainer (like Zyprexa, say) but I have heard of people putting on weight with it, which is one reason I ruled it out. I think Latuda is much better in that regard, but it also can cause akathisia. I take 80mg propranolol for that. I would anyway; it's well worth it for me, but I admit I would be taking a just a heart-specific beta blocker anyway for the PVC.The propranolol of course works for both.