Janice McConnell, DVM, CCRT, cVMA
Treating Chronic Osteoarthritis Pain in Our Pets Osteoarthritis (OA) is a common cause of chronic pain in our pets. It is estimated that 20-25% of adult dogs develop osteoarthritis, and that number may increase to 80% of geriatric canine patients over 8 years of age. In studies of cats, the prevalence of radiographic changes of OA ranged from 22-33% when all ages were included; and prevalence went up to 90% in cats over the age of 12 years. Recognition of chronic pain in our pets can be challenging, as the symptoms are often subtle. Please talk to your veterinarian for guidance on how to recognize pain in dogs and cats.
When we identify that a pet is painful due to osteoarthritis, we assess the nature and severity of that pain to develop a short and long-term treatment plan that will best support joint health and the pet’s function.
We are fortunate to have a variety of therapeutic approaches to choose from and we will be most successful if we take a multi-modal approach to pain relief. The following list is intended to provide information on some available treatment options, including medications, nutraceuticals, and physical rehabilitation methods that can be utilized as part of a multi-modal pain management plan for your pet. While this list is not comprehensive, it does focus on the more commonly prescribed therapies and those with evidential support.
1) Non-steroidal Anti-inflammatory drugs (NSAIDs): NSAIDs, such as carprofen and meloxicam, are still the mainstay for osteoarthritis care and can be used safely longterm in many OA patients.
2) Galliprant is a new medication that targets a specific prostaglandin receptor involved in mediating inflammation, rather that inhibiting production of prostaglandins, as the NSAIDs do. This medication holds promise for control of OA pain and may be tolerated by some patients that cannot take NSAIDs.
3) Gabapentin plays a role in managing neuropathic pain and has become increasingly prescribed for chronic OA pain. While we have appreciated some benefit of this medication, we still lack studies to support it’s benefit for our OA patients.
4) Amantadine is a medication that helps to prevent or control ‘wind-up pain’. Wind-up pain results when the central nervous system becomes sensitized to repeated pain signals. The result is a more intense and frequent firing of pain signals, and thus the perception of pain become stronger and more persistent. If your pet’s chronic pain is moderate to severe and does not respond well to NSAIDs alone, a course of amantadine may be warranted. Nutraceuticals There are many nutraceutical options on the market, many of which can provide benefit in OA care. But given the lack of regulatory standards on supplements, we will best serve our pets by being mindful toward potential harmful substances in over-the-counter products, and by seeking out good quality control and evidence to support efficacy.
1) Omega-3 fatty acids are beneficial for OA by reducing inflammatory mediators. Eicosapentanoic acid (EPA) and Docosahexanoic acid (DHA) are the key omega-3 fatty acids for dogs and found in fish oil. It is important, however, to understand that not all fish oils are equal nor safe. Things to consider when researching a company include whether the source of fish is certified sustainable, and whether every batch of product is tested for toxins and contaminants. Dosing in dogs for joint care starts from 50-100 mg/kg per day of combined EPA/DHA.
2) Polysulfated Glycosaminoglycans (PSGAGs). Adequan ® is an FDA-approved injectable disease modifying osteoarthritis drug that provides cartilage protection by inhibiting enzymes that break down cartilage. There is good evidence to support that the product reaches the joints and helps clinically to reduce pain.
3) Glucosamine/Chondroitin support cartilage health and protection from damaging enzymes but a review of the studies demonstrates mixed results. The data do indicate better absorption and clinical results with low molecular weight chondroitin, as is found in Cosequin® and Dasuquin®.
4) Avocado/Soybean Unsaponifiables (ASU) appear to work synergistically with glucosamine and low-molecular weight chondroitin to support cartilage health and may inhibit some mediators of pain.
5) Others: There are a few other products that deserve mention and may hold promise for joint care but still lack robust clinical data. Curcumin (a substance in the spice turmeric) may help reduce inflammatory mediators. Green-lipped mussel contains components that appear to have anti-inflammatory and joint protective effects. Microlactin is a milk-derived protein with anti-inflammatory effects. Elk Velvet Antler contains glucosamine, chondroitin, and other factors that appear to have an antiinflammatory effect and may promote an increase in muscle mass. Cannabidiol (CBD) products are currently widely available for dogs and cats and have seen mixed results, perhaps due to a lack of data on dosage and production variability. There is currently a clinical study at Colorado State University on use of CBD in osteoarthritis patients and we look forward to the results!
Arguably the most important thing you can do for your dog with osteoarthritis is to keep him/her lean. Weight loss in even mildly overweight animals can significantly reduce pain from osteoarthritis. And the additional health benefits of weight management include longer life span and slower onset of symptoms of other chronic diseases. Please work with your veterinary team to develop a weight control program and monitor the weight loss in your dog. We recommend targeting no more than a 1% weight loss per week.
Physical rehabilitation offers several non-pharmaceutical options to provide adjunct pain control and anti-inflammatory effects:
1) LASER stands for Light Amplification by Stimulated Emission of Radiation. Therapeutic lasers are used for photobiomodulation – they emit light waves at specified wavelengths to stimulate cellular change. Clinical effects include a reduction in pain and inflammation, and enhanced tissue repair.
2) Acupuncture is a means of neuro-modulation by placing needles in specified locations to elicit a physiologic response and enhance endogenous pain mechanisms.
3) Therapeutic Massage can relieve pain and stress, improve blood flow and lymphatic drainage, relieve local muscle tension, and reduce myofascial dysfunction.
4) Pulsed Electromagnetic Field Therapy (PEMF) uses electromagnetic fields to induce cellular changes, and shows benefit for wound healing, bone healing, pain management and reduction of inflammation.
5) TENS delivers an electrical currently across an area of injury and can help reduce swelling as well as provide pain control.
6) Therapeutic Ultrasound sends sound waves into tissues to reduce pain & inflammation, and heat tissues to relax them and allow stretch.
7) Joint mobilizations done by a trained rehabilitation therapist can reduce pain in a diseased joint and improve range of motion of a joint.
Positive effects of regular therapeutic exercise in OA patients include maintaining mobility of affected joints through daily activity, strengthening the muscles around affected joints, improving balance, and weight control. An appropriate and safe therapeutic exercise program for your dog is best developed by a therapist trained in canine rehabilitation.