ANY nsaid (non-steroidal anti-inflammatory drug) can cause gastric bleeding, liver problems and kidney problems. So can that aspirin you may take yourself.
It's one of the reasons why many of us who post here warn repeatedly about certain drugs like this. But even more pertinent -- ***YOU need to ask*** at the vet. When the vet prescribes something say something like "Tell me about potential side effects please?" You don't need to be abrupt or nasty -- just willing to hear and understand. Most people don't WANT to hear that kind of stuff (their eyes glaze over, the brain freezes) so vets don't tell them because it's a relatively safe thing.
People ignore safety warnings ALL the time. But it's honestly on the individual. Both in your own health and your pet's health -- to investigate these things on your own.
Now -- what do you do NOW?
1. milk thistle. It's safer and far far less expensive than marin. (marin is a good drug -- it's the pharmaceutical version of milk thistle -- highly refined so it's not an 'herb' any more ... but that also tends to decrease it's safety).
You can get milk thistle at Wal-Mart to start with. Milk thistle helps protect the liver and it helps detox the liver. But since Riley's body has seen the Rimadyl as a 'toxin' and it's made the stomach sore, you'd be wise to do milk thistle.
2. chamomile tea -- cheap and easily found anywhere. Grocery store - but get **plain** chamomile (not with green tea or vanilla or anything else in it -- just plain chamomile). Brew the herbs and let it sit until cool. Add the soggy herbs to Riley's next meal (they don't taste bad). Add just a tiny bit of beef broth or honey to the tea -- and Riley will likely drink some on his own. Add it to his food. Use a baby syringe to squirt behind the canine tooth (hold the mouth loosely shut -- so he can work his tongue to swallow).
Chamomile is healing to the stomach.
3. Here's my vet's "slippery elm cocktail" recipe. This works INCREDIBLY WELL on gastric bleeding and ulcers. It helps heal the stomach:
SLIPPERY ELM COCKTAIL
1 -- half a cup of boiling water.
2 -- add 1 rounded tsp. of ground slippery elm
3 -- let cool totally
4 -- add 1/8 c. + 2 tablespoons of aloe juice
5 -- add 10 drops of chlorophyll
6 -- Add 2-3 capsules (open the caps) of acidolpholus
Once you get it mixed up and whipped smooth, it keeps in the fridge for 3-4 days (after that the acidopholous dies).
Use a baby medicine syringe and load it FULL. Give about half an hour before a meal. Just put the tip of the syringe behind the canine tooth and hold the mouth loosely closed. Squirt slowly so they can work their tongue to swallow.
Where to get the stuff:
Slippery elm you can get at most health stores -- if they don't typically sell it in bulk they may have slippery elm 'tea' in bulk (that's the same thing).
Chlorophyl -- you only need a bit -- but most health stores sell it and you may have to buy a big bottle
Acidopholus - that's a probiotic. Get it again, at a health store. Just get a good general acidopholus.
This has to be refrigerated. It doesn't "spoil" in 3 days -- but the probiotic will die. (a probiotic is live "good" bacteria).
Aloe -- you can also buy this at a health store (Wal-mart carries this too usually). But you need one that is consumable (you drink it).
Notice the directions above say "1/2 hr before a meal". That's so it coats the stomach and soothes it so it's not too sore to receive food.
Kibble may not work -- because it's rough (and the stomach lining is SORE -- so rough kibble is .. yep, scratchy and more sore). I would cook up ground beef and rice. Don't use chicken -- it's too inflammatory. There's a recipe in this on my website: http://www.critturs.com/prissy.html
I'd keep Riley on soft food for a week or so. BLAND diet. Easy to digest. When you cook the rice way way **way** overcook it. Don't use brown rice it's too hard to digest. But rice made with extra water, cooked until it's blown apart and mushy.
In future? You will likely want to pay more attention to the health stuff. Recently Bugsy reacted badly to Rimadyl. You've got a new puppy -- and frankly you may want to become far far more aware of things like vaccines and common stuff to prevent problems in the little one. Poodles are delicate in many many ways.
Holler if I can help.
Don't get mad -- just become determined to know more. Rimadyl, and the other dog nsaids, are FAMOUS for this stuff. They can be used fine and easily with many dogs ... and then there is the one dog who becomes sensitive to it. The answer is *you* becoming more aware. It really is.