Our dog is going to be 8 years old in november. Our veterinary put him on Piroxicam capsule. We give him 1 capsule by month once daily. We started these capsules on Friday, since he has been on the medication he was been acting weird. Yesterday, he can hardly stand up and walk today he was walking and fell over and he was making weird noises. Then he snapped out of it and he got up really slowly. What are the side effects that we need to look for when taking this medication. We won't be able to talk to our veterinary until tomorrow when he opens. Please let me know.