Behaviour change in German Shepherd

Question
Patt, I need some urgent advice. For the last two weeks my 6 year old GS has been behaving strangely. He is waking up early and his back legs are shaking badly. He is very aggitated and acting as though something has spooked him. At the first opportunity he bolts downstairs to large room rarely used.He is very close to me but won't even come up when I gently try to coax him.He hs escaped from the garden when my husband and I are out by destroying a strong wooden fence, hurting himself in the process. We also have a 4yr old Rottweiller and the two dogs get along very well and sleep close to each other at night. At first I thought there might be a battle going on for Alpha dog status between them but there is no evidence of that and we always treat the GS as the alpha dog by feeding him first. The rottie doesn't seem to be bothered by this and is very well behaved.Our GS has problems with aggerssion towards other dogs,not our Rottie though,  due to him not being socialised thoroughly as a pup as he was housebound for 6 weeks due to an operation he had to correct a leg problem.We deal with that aggression by using the usual training methods while out walking him. He has also had obedience training. Otherwise he is a very lovable, much loved dog but we are at a loss as to what is wrong with him. The vet has put him on Clomicalm and Valium. I am really concerned that while he is in this state he is going to hurt himself or escape and hurt someone else out of fear.Any suggestions you may have will be very welcome.
Helen PS, We have already spent a fortune on taking him to a dog behaviour specialist re his dog aggression so that really isn't a viable option at this time.  

Answer
Helen
Has his hips been xrayed, this could be the onset of Hip Displaia. Instead of the downers, he should be taking glclosemine, spelling is wrong, but it is a natural pain reliever.  Pain could be pushin him over the edge so the speak.  He is the age it sets in as Arthritis, but really HD it is.
If he is in pain it does strange things to a dog.  Keep him confined not running, but walking till u know for sure.  If it is, then stop the drugs.  That in itself will put him in a drug induced stage of not knowing what he is to do right.  He cannot even think at this point with Valium I would never allow this given to any of my dogs even when coming from Germany I state NO DRUGS.
Try buying this at wal marts in the dog section Glucsomine.
Give it a few days even give him more than it states to get into his system.  Let me know if this works.

Kind Regards
Patt
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