Feldene for dogs with poor renal function
Dear OncoLink "Ask The Experts,"
My dog has been diagnosed with renal carcinoma. It was suggested to use Feldene (piroxicam) to help slow down the progression of the cancer. I have concerns due to the fact that my dog has only one kidney. Her Vet removed the other due to the cancer/tumor. I read in the article that was e-mailed to me that Feldene should not be given to dogs with poor kidney function. Is it safe to give my dog this drug if she has only one kidney?
Lili Duda, VMD, Section Editor of the OncoLink Veterinary Oncology Menu, responds:
Piroxicam (Feldene) is one of a family of non-steroidal anti-inflammatory drugs (NSAIDs). They have two potential roles in treating cancer in veterinary patients. First, they are effective at alleviating pain and inflammation associated with many large tumors, and therefore help improve quality of life. Second, they function as COX inhibitors, which may have some direct anti-tumor activity in a variety of cancers.
COX (cyclooxygenase) enzymes come in two forms COX-1 and COX-2. COX-1 is produced by a variety of cells in the body and is necessary for normal functions, including protecting the kidneys and the lining of the stomach. COX-2 is produced during inflammatory states and by many cancers. Some early NSAIDs non-specifically inhibit both COX-1 and COX-2, so while they effectively reduce inflammation and might inhibit or kill some cancer cells, they also could cause gastrointestinal ulceration and impairment of kidney function, particularly with prolonged use. Some of the newer NSAIDs have been designed to be much more active against COX-2 while not affecting COX-1, with the goal of preserving anti-inflammatory and possibly anti-tumor effects while minimizing the risk of side-effects. Deramaxx (deracoxib) is just such a new veterinary drug, and many veterinary oncologists are starting to prescribe it for animals in which piroxicam might be contraindicated. However, its anti-cancer activity is as yet undetermined.
There are also several other veterinary NSAIDS that might be useful in your dog. Some oncologists are also starting to prescribe omega-3 fatty acid supplementation such as is available in the veterinary Hill's n/d diet (n/d stands for neoplasia diet) in conjunction with NSAIDs. It should be clear that NSAIDs with or without fatty acid supplementation are still completely unproven as beneficial for most veterinary cancers, and should not be used as a substitute for conventional treatment options when those are available. However, they are relatively safe and offer some benefit apart from any potential anti-tumor activity.
Regarding your dog in particular--one normal kidney is more than adequate to maintain normal functioning. As long as kidney function is monitored routinely (through urine specific gravity, which measures the kidney's concentrating ability in conjunction with two blood tests--BUN (blood urea nitrogen) and creatinine), NSAIDs should be safe to use in your dog.