My dog is taking Previcox and Prednisone, is this harmful?

My dog is eleven, he weights 13lbs and has been diagnosed with MCTs Grade 3. The Vet prescribed Previcox 57mg,  Prednisone 5mg and Benedryl 12.5mg . Last night after giving him the Previcox and Benedryl he started breathing so heavily it was awful. I read online that Previcox and Prednisone should not be taken together. I haven't given him any medication this morning and his breathing is normal and he seems more alert.

[Aleda M Cheng, D.V.M., C.V.A]

Previcox and Prednisone should not be given together.  This combination increases the danger of gastrointestinal ulceration and other problems which can be dangerous.  

Benadryl should be safe, but it can rarely cause breathing problems.  Prednisone can also cause increased panting.

Previcox can be safely used with Tramadol (another analgesic), if the Previcox is insufficient alone.

Put your dog on 5mg. of Pepcid twice daily to try and prevent GI issues. Pepcid is available over the counter.

[Tinycountrybees]

Dr Cheng, thank you so much, for taking the time to read my question. I will try the Pepcid and ask that he be put on some other type of medication. I keep reading that Previcox and Prednisone aren't a good combination.