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Osteoarthritis in Dogs

  • January 23, 2017 6:16 PM EST

    Osteoarthritis is very common in dogs, and it is estimated that 20% of dogs over one year of age have osteoarthritis. It can certainly develop in dogs at any age or in any breed, however risk factors for the development and progresssion include increased age (it is more common in older dogs) and increased body weight (not only size of dog, but also if there is excessive body weight in any individual of any breed).

    The hallmark of osteoarthritis is inflammation, and this can lead to joint cartilage damage and pain. The pain can result in disability, and this is evidenced by decreased activity or the overall impression of a decreased quality of life.

    Inflammation and Osteoarthritis

    Understanding the mechanism for the inflammation and pain becomes important when we start to consider options for treating patients with osteoarthritis. We know that the key mediator of the redness, swelling, and pain associated with inflammation is a prostanoid - specifically, prostaglandin E2 (PGE2).

    Prostanoids are widespread throughout the body, and they can be further characterized as either “good” or “bad.” The “good” prostanoids are those that have important physiologic functions. These prostanoids are involved in the regulation of blood flow to the kidney, gastrointestinal health and healing of GI ulcers, blood clotting, immune function, among others.  “Bad” prostanoids are mediators of pain and inflammation.

    Treatment of Osteoarthritis

    When treating patients with osteoarthritis there are two major goals. The first goal is to slow the progression of the disease, and unfortunately, this is a bit of a challenge. The other goal of therapy is to minimize the signs associated with inflammation and pain. This is typically where we think about pharmacologic management. Ideally, though, a multimodal approach often works out best for the patient (if a number of modalities are considered and implemented). These include:

    • Weight Management

    One of the most important considerations for patients with osteoarthritis is weight management. Achieving an ideal body weight is important, as it helps to reduce the physical load on those joints. In addition, identifying any comorbidities or underlying conditions that could cause a patient to gain excessive body weight is also important. A good work-up for any patient, for example, might include screening for metabolic abnormalities such as hypothyroidism or Cushing's disease.

    • Nutrition

    Good nutrition is not only very important for weight management but it's also important because a number of supplements have anti-inflammatory properties. Omega 3 fatty acids, for example, would be among the nutritional supplements that can be used to help patients with osteoarthritis.  Learn more about supplements and nutrition

    • Controlled Exercise 

    A controlled exercise program is really important in the management of patients with osteoarthritis. Exercise helps to get those joints moving and can also help to contribute to weight management. Although it seems counterintuitive, getting the patient moving in a controlled fashion (one that doesn't want to move much because it is in pain), can actually help the patient to feel better.

    • Rehabilitation and integrative modalities

    Incorporating physical rehabilitation and integrative modalities can be very helpful in managing patients with osteoarthritis. Some of these modalities include therapeutic exercises, water therapy, laser, TENS / neuromuscular electrical stimulation, and pulsed electromagnetic field therapy.

    • Drugs / Pharmacologic Management

    The anti-inflammatories tend to be the mainstay of treatment. [The 2015 AAHA/AAFP task force published their consensus on pain management for dogs and cats - which is summarized in our Specialty Update - View On Demand].  Generally speaking, options include:

    1. Steroids: 
      Steroids are really only appropriate if the osteoarthritis is associated with an autoimmune process. Steroids are a very poor choice for long-term therapy, primarily because of their side effects, and they just don't work as well as the non-steroidal anti-inflammatory drugs (NSAIDS).

    2. NSAIDS:
      Traditional nonsteroidal anti-inflammatory drugs (NSAIDS) work by inhibiting the COX enzyme which is involved in producing mediators of pain and inflammation. The COX inhibitors can be non-selective (inhibiting both COX-1 and COX-2: products including aspirin, ibuprofen, indomethacin) or they can be selective (COX-2 inhibitors - products including carprofen, meloxicam, and other -coxibs).  Selective COX-2 inhibitors have been promoted to be safer and more protective of the constitutive / "good" prostanoids. We have still found that there are some potential side effects associated with these drugs. 

      Non-selective COX-inhibiting nonsteroidals can potentiate GI ulceration, inhibit the healing of GI ulcers, and contribute to renal insufficiency or liver toxicity. The "safer," selective COX-inhibiting nonsteroidals can also have side effects and sometimes are not well-tolerated by the patient.

    3. Piprants
      There is a relatively newer class of drugs called the Piprant class of drugs - which was recognized by the World Health Organization in 2013. These drugs are prostaglandin receptor antagonists – they prevent the binding of PGE2 to its receptor, thereby preventing PGE2 activity. This drug is FDA-approved for use in dogs and has just been released this year. 

      A prospective study of dogs with osteoarthritis showed that one piprant - grapiprant - promoted 
      significantly better pain control in grapiprant-treated versus the placebo-treated dogs.  In addition, veterinary assessments demonstrated significant improvement in the total orthopedic scores in the grapiprant-treated dogs compared to the placebo-treated dogs. 

      The drug was well-tolerated and treated dogs had minimal adverse events. Grapiprant appears to be an exciting new treatment option to consider for dogs affected with osteoarthritis. It seems to be at least comparable in effectiveness and safer compared to other NSAIDS. Although treated dogs may develop mild GI disturbances when taking the drug (vomiting, soft stool, and inappetence), adverse effects on platelets and kidney and liver function were not seen, and dogs showed no evidence of GI ulceration.

      Learn More about A Novel Therapy for Managing Osteoarthritis in Dogs