Is the Deramaxx a lot like aspirin? I was using aspirin to start off & it didn't help with Bob's stiffness & pain. The veterinary has never drawn any blood from Bob. Bob was in for his yearly check up & normal dog shoots in July. Doc didn't seemed concerned as long as the Rimadyl was keeping the stiffness & pain away. Bob had been hit on the road when he was about 2 years old. I took him in for x rays & his right leg & hip had a fracture. Doc would not give him any medicine then. He said Bob would have to endure the pain because getting up & running around with pain medicine would not help the healing. So Bob was confined to the barn in deep straw while he healed. It healed but Bob could not really put his foot down normal for a long time but eventually he did get his leg & foot to work normally again. I figured when he got older he would have problems & so it has come to the Rimadyl.