As they age, approximately 20 percent of dogs experience osteoarthritis, a condition exacerbated by excess weight as well as by stress on joints from working or performance activities. Breeds such as golden and Labrador retrievers are overrepresented, but degenerative joint disease isn't limited to highly active dogs or even to old dogs.
"You could have a young dog that has a congenital condition, maybe hip or elbow dysplasia," said Joyce A. Login, DVM, Zoetis senior manager of veterinary specialty operations. "It's born with that, which is going to set it up for osteoarthritis. That can happen when it's 3 years old; it doesn't have to be 15 years old."
No matter what age or type of pet—cats are at risk, too—managing osteoarthritis calls for early recognition and a multimodal approach to pain and inflammation incorporating weight loss, rehabilitation techniques, and specific types of drugs that reach specific targets in the body. There's no silver bullet, Dr. Login said, but multiple modalities, including NSAIDs, exercise, chondroprotectants, diet, acupuncture, and laser can all contribute to supporting the well-being of a dog or cat with osteoarthritis.
DMOADs
One of those modalities is the use of disease-modifying osteoarthritis drugs (DMOAD). Products in this category include Adequan Canine and Zydax.
DMOADs have an indirect anti-inflammatory effect, appearing to reduce inflammation in joints by healing microfractures in cartilage, thickening viscosity of synovial fluid, and downregulating enzymes that degrade cartilage. Ancillary benefits include reduction of swelling and improved blood flow.
All characteristics that make Adequan a useful adjunct to other drugs and techniques, said pain expert Robin Downing, DVM, DAAPM, DACVSMR, at Downing Center for Animal Pain Management in Windsor, Colo. While it can't rebuild cartilage, it appears to aid in its preservation.
Another veterinarian who has found DMOADs beneficial in her practice is Kathryn Primm, DVM, owner of Applebrook Animal Hospital, in Ooltewah, Tenn.
"I have one recent case in particular who is an elderly Lab," Dr. Primm said. "She suffers from osteoarthritis pain, but always has elevations of her liver enzymes. We added Adequan injections to try to reduce the amount of other pain coverage that she needs to try and spare her liver. The owner felt that she was helped for a time, and we started another round yesterday."
To help prevent cartilage degradation and loss, DMOADs are best administered early in the disease process. Using them when osteoarthritis is first diagnosed may help to delay disease progression and the need for more aggressive treatment with NSAIDs.
NSAIDs
Nonsteroidal anti-inflammatory drugs, such as include Rimadyl (carprofen), deracoxib (Deramaxx), Meloxidyl (meloxicam), and quellin (carprofen) as well as Galliprant (grapiprant), a prostaglandin receptor antagonist, remain the mainstay of pain management due to their effectiveness at reducing pain and inflammation.
"They are a godsend," said Alicia M. Karas, DVM, MS, DACVAA, an assistant professor of anesthesia and pain medicine at the Tufts University Cummings School of Veterinary Medicine. "These specific NSAIDs that have been made for dogs and cats have really revolutionized animal comfort.
"At the same time, they are capable of causing adverse effects," Dr. Karas said. "Practitioners often have a healthy awareness of the fact that they should be careful, but if there's one thing that I've found from my interactions with clients, it's that they do not understand the medications we are giving them at all."
Veterinarians cannot emphasize enough to pet owners about the way NSAIDs are to be used.
"[Clients] will not realize they can't give another nonsteroidal like aspirin," she said. "They will not report what they are giving when they go to the emergency room, and they will double the dose because 'If some is good, more is better.'"
A somewhat recent finding about NSAIDs, particularly for chronic pain patients, is that longer-term use might be a better approach, said B. Duncan X. Lascelles, BVsc, Ph.D., CertVA, DACVS, professor of surgery and pain management at the North Carolina State University College of Veterinary Medicine.
"That doesn't necessarily mean lifetime use," said Dr. Lascelles. "It just means a longer-term use to, in particular, help reset the central nervous system."
The topic of giving cats NSAIDs like robenacoxib (Onsior) and meloxicam (Metacam) can be complicated.
"Veterinarians in the United States are at a loss for what to use for chronic pain in cats," Karas said. "Despite what I'm presenting to veterinary students, they come out of fourth year thinking you can't use nonsteroidals chronically in cats. And that's what most veterinarians think. They think that because of the black-box warning on Metacam."
Robenacoxib can be effective for cats suffering from chronic osteoarthritis pain, but some veterinarians are hesitant to use it if the patient has concurrent kidney disease. However, a recent study found that robenacoxib was well-tolerated when given daily for one month to osteoarthritic cats, even if the animals showed evidence of chronic kidney disease.
When veterinarians have a patient that does not tolerate one NSAID, they might wonder about trying a different one.
"I have had patients who could not tolerate carprofen [due to stomach upset] who did just fine on meloxicam, and vice versa," said Dr. Downing. "That said, if I have a patient who experiences any adverse event with two NSAIDs, then I choose not to offer a third. Odds are pretty good at that point that I have a patient who simply cannot tolerate this class of medication."
Downing also doesn't recommend rotating different NSAIDs over time.
"There is really no compelling evidence to suggest that this is useful, and no controlled studies to suggest it should be or needs to be done," she said.
Multimodal treatments
"I like to utilize sensible exercise and rehab for strengthening, acupuncture for pain control, close attention to weight control, including OA diets, and the use of other pharmaceuticals for pain control," said Michael C. Petty, DVM, DAAPM, owner of the Animal Pain Center of Arbor Pointe Veterinary Hospital in Canton, Mich.
"There are several areas of multimodal management of OA pain and not every patient is going to need all of them," said Rick Wall, DVM, CCPR, DAAPM, owner of Animal Clinics of The Woodlands and the Center for Veterinary Pain Management and Rehabilitation in The Woodlands, Texas.
Using them in various combinations will yield the greatest success, he said: weight loss; exercise; pharmaceuticals; adjunct pharmaceuticals, most of which don't have FDA approval for use in pets but are widely accepted in veterinary medicine; physical medicine modalities such as therapeutic laser therapy, extracorporeal shock wave, trigger-point therapy, and acupuncture; rehabilitation; and nutraceuticals.
At the Downing Center, normalizing a pet's weight is the first step in OA pain management.
"Without weight loss for overweight pets, pain management will be a tepid success at best," she said.
Bringing clients on board
The most important factor in managing osteoarthritis is client communication. Many clients may not realize that their animal is in pain or that something can be done about it. Approaching them can require diplomacy and hands-on demonstrations.
Do more than give clients a handout or point them to a website, Dr. Login said. Bring up the possibility during a visit, and draw clients out with questions about changes in the pet's behavior.
Behavioral changes that clients may attribute to the vagaries of aging instead of to pain include whether the animal is slower to rise, hesitates to go down stairs, doesn't want to walk as far, breaks housetraining or litterbox training, has difficulty eating or, in the case of cats, groom themselves less frequently or less effectively. Look for postural clues the pet may be exhibiting in the exam room. She may be leaning to one side or putting less weight on a particular limb.
Before performing a pain palpation on a pet, Downing demonstrates on the client's forearm the amount of pressure she'll be using. This gives owners a frame of reference when they see a pet's reaction to being touched in a particular area. It's a good way to help clients recognize that what should be an innocuous touch is painful.
When clients see pets react by twitching their skin, attempting to move away, crying out, or even trying to bite, they are often shocked to realize that their pet has been in pain. The revelation is an opportunity to discuss where the pain is occurring, why, and what can be done to break the pain cycle quickly and effectively.
While there isn't a cure for osteoarthritis, a multimodal treatment plan can help bring long-term relief to dogs and cats.
