Evidently the Princess Royal is susceptible to the tardive dyskinesia (uncontrollable muscle movements) reaction in some anti-psychotic drugs. So far she's had this reaction to 3 drugs. So now she's miserable with head twisting/jerking (intermittent thankfully) until the medication clears her system. It's been about 24 to 30 hours and has a (?) while to go. The treatment is OTC Benadryl, so she's going to be sleepy as well. I just have to be with her when they occur, about 2 or 3 times an hour. Boring as all get out for me, but much worse for her.