human pain medication for dogs

Question
My dog has a pulled muscle on his right front leg and is in alot of pain, rimadyl for dogs is not working and is expensive and at this time I can't afford to take him back to the vet, is it safe to use oxycodone or ibuprofen and if so how much is safe?  I have given him coated aspirin in the past but doesnt really seem to do the trick.  He is a 130 pound rotweiller/german shepherd mix, who is otherwise in good health, thanks for any feedback.  Sincerely,
                         A concerned parent

Answer
Hi Sonia.  Never, ever give a dog ibuprofen, tylenol, ect., as it causes irregular heart beats and can cause a dog to go into cardiac arrest.  Baby buffered asprin is the only over-the-counter, human medication for pain that can be safely given.  How much rimadyl is your dog on?  Let me know, and possibly, with a medication increase, it may work to ease some pain.  I would recommend having the ligament in his front leg checked, as he may have torn it, which is very common to happen in large dogs.
He is a very large dog in weight and he may be on a minimum dosage of the rimadyl.  Rimadyl is the very best medication for this so we'll try to make it work:)
Please let me know his current dosage,
Hilary