Parker has taken carprofen for about a year, 50 mg with each meal, to help with his arthritis and back pain. Starting yesterday I upped it to 100 mg at breakfast.
More carprofen meant less pain almost immediately. His walking pace improved about 10% today and he has seemed more active and more confident of his footing. He seems like the dog he was a year ago.
But at his body weight, 100 mg per day is the maximum safe dose. Carprofen, like NSAIDs in general, puts a lot of stress on the body, particularly in the kidneys and liver. At 150 mg a day, he would likely have noticeable and perhaps irreversible kidney and liver damage within a couple of months. Half a year at that dose could kill him.
So it's a bittersweet choice. It will make the time he has left more comfortable for him, but maybe a bit harder for me.
Update: Here's more information about carprofen, in particular that the recommended dose is 4.4 mg/Kg per day. Parker weighs about 25 kg, giving him a recommended daily dose of 110 mg.