Did you realize that 62% of dogs between 8 and 13 years of age have arthritis? And that 20% of all cats have x-ray evidence of arthritis? Some orthopedists believe that osteoarthritis disease (OAD) in dogs is caused by an anatomical defect that places abnormal stress on the joints. Wear and tear arthritis tends to occur in cats much as it does in people. No matter the cause of OAD, alleviating pain is the primary concern. OAD pain signs can include limping, difficulty jumping, sitting or squatting to eliminate, stiffness, reluctance to navigate stairs and overall behavior change. If your pet is demonstrating any of these signs as it ages, it may be time for life improving OAD therapy.
Think of OAD therapy as a triangle. Each leg of the triangle represents one mode of therapy: chondroprotectants, NSAIDs (Non Steroidal Anti-Inflammatory Drugs) and adjuvant pain relievers. The inner area encompassed by the triangle legs represents weight management which is often a too overlooked part of arthritis control.
Chondroprotectants are substances while help protect cartilage. Joint fluid and cartilage act as shock absorbers for bones. Chondroprotectants help maintain cartilage integrity and help increase joint fluid viscosity. There is only one injectable FDA approved chondroprotectant. All others are nutraceuticals such as glucosamine or dietary supplements some of which are incorporated into the food. There is a wide variation of efficacy in these substances so please consult with your veterinarian about their use.
The next triangle leg is the NSAIDs- the largest group and mainstay of OAD treatment. NSAIDs block the cyclo-oxygenase (COX) pathway. The COX pathway is responsible for prostaglandin production. There are two primary COX pathways- COX 1 & COX 2. The COX 1 pathway synthesizes beneficial, “housekeeping” prostaglandins that aid in maintaining gastrointestinal mucosa, kidney blood flow and platelet aggregation which helps blood clot. COX 1 is known as the “good COX”. The COX 2 pathway produces inflammatory prostaglandins which cause inflammation and pain. Some inflammation is good and helps the body repair damage, but chronic inflammation isn’t beneficial to the body. COX 2 is “the bad COX”. The newer, more potent NSAIDs inhibit the COX 2 pathway while mostly sparing the COX 1 pathway making these new class of drugs much safer. Aspirin and corticosteroids work by inhibiting both the COX 1 and the COX 2 pathways. Aspirin’s action of interfering with gastric protection prostaglandins predisposes dogs and people to gastrointestinal ulceration. This side effect is rarely seen with the selective COX 2 inhibitor NSAIDs such as Rimadyl, Deramaxx, Metacam and Previcox. There are side effects associated with this group of drugs so your pet will need to have periodic, monitoring bloodwork done. I also recommend doing baseline bloodwork prior to initiating therapy since often we are using these drugs in our older patients which may have other, underlying, hidden health issues.
A reminder note: In general, NSAIDs are toxic to cats. NSAIDs such as Tylenol (Acetaminophen) and Advil (Ibuprofen) can induce fatal liver failure in your cat. NEVER give your cat NSAIDs.
The third leg of the OAD treatment triangle is pain relievers other than NSAIDS. Narcotic and narcotic-like drugs represent a large portion of this group. These drugs make up the mainstay of OAD control for cats. Unlike NSAIDs, narcotics can be used safely in cats under close supervision of a veterinarian. In canine patients, adding a narcotic or narcotic like drug into the treatment regimen along with the NSAIDs will allow us to use the lowest NSAID dose possible. Lowering the NSAID dose reduces the potential side effects of the NSAID. Moreover, many dogs with severe OAD require this multi-modal pain relief therapy to achieve pain control. A common drug now used to treat the pain of canine OAD is tramadol. Many of you know this drug as Ultram.
Lastly, weight management is the overall key to controlling OAD. That is why it is represented as the center of the triangle. Additional body weight stresses joints. A higher fiber, low fat diet will help your pet lose weight, decrease joint pain and hopefully decrease the overall doses of medication needed. Weight loss will also help your pet move more easily and this in turn will aid you with implementing a moderate exercise plan. Regular controlled exercise can improve joint mobility and strengthen supporting muscles which can improve your pet’s quality of life. Physical therapy is a new and upcoming area of treatment for patients with OAD.