Do you mean EcoTRIN? If so, that is aspirin. My own vet does not recommend aspirin for dogs under any circumstances, and certainly not for chronic arthritis pain. While he admits it's effective and most dogs have no problem with it, he did have clients whose dogs ended up with bleeding ulcers. One dog nearly bled to death from his stomach after only two doses, so that's why he went completely against using it.
An over-the-counter alternative is tylenol, but having used it on my own older dogs I found it to be ineffective. Check with your vet for proper dosage amounts if you decide to try it.
If tylenol doesn't help, then you'll need a better anti-inflammatory med from your vet. Rimadyl is old enough to be a cheap and effective medication. I had one dog on it for almost 7 years for hip dysplasia and he did fine. We eventually had to change to Deramaxx when the rimadyl wasn't working as well, and I have to say I'm a total deramaxx fan. It can be expensive if your dog need a high dose, but since your dog is small it shouldn't be too bad.
One prescription med I can't recommend is etogesic. I tried it with 3 of my dogs and every one of them ended up with either vomiting, diarrhea or both within a couple of days. The same thing happened to my sister's dog and my neighbor's dog.
Before I forget, congratulations on the great care you've given your dog. Sixteen years is incredible! :-)
I agree with Jaybay, Deramaxx works really good. We only gave it to our dog when she was having a really bad day, it worked fast and did wonders.
Ascriptin is a coated spirin that has been used for years in the treatment of arthritis.Aspirin is routinely used in dogs and is considerd a accepted practice.NSAID's tend to cause some adverse effects on the GI tract and the kidneys.Some furbabies are more sensitive than others.Any aspirin should not be used with corticosteroids unless they are being watched by there Dr.
Rimadyl is also a good NSAID.It is believed to work by inhibiting the production of prostaglandins and other chemicals in the body that sentitize pain.It can be given twice daily .Etogesic works really good for pain also and is given once daily.Dermaxx works really well on controlling pain as well and alot of vets give it after procedure is done in the office.It is a little stronger than Rimadyl,But works along the same way.It is really what you feel the most comfortable in giving your baby and what works the best for him.I have used all the meds above on my babies and each one responds to them different.My Pyrnees uses the Ascriptin and my Pekingese use Rimadyl and Ectogesic.Good luck and take care