A rational approach to osteoarthritis management (Proceedings) - Veterinary Healthcare


A rational approach to osteoarthritis management (Proceedings)


Adverse Events

The most common problems associated with NSAID administration to dogs and cats involve the gastrointestinal (GI) tract. Signs may range from vomiting and diarrhea, including hematemesis and melena, to a silent ulcer which results in perforation. Concurrent administration of other medications (especially other NSAIDs or corticosteroids), previous GI bleeding, or the presence of other systemic diseases may contribute to adverse reactions. Hepatotoxicosis can occur, and is generally considered to be idiosyncratic. Most dogs recover with cessation of treatment and supportive care. Renal dysfunction may occur with NSAID administration as a consequence of prostaglandin inhibition. In hypovolemic animals prostaglandin synthesis is increased to maintain renal perfusion; NSAID use in these patients must be considered very carefully.

Multimodal Therapy

There is a move towards greater use of a multimodal therapeutic approach to treat chronic pain in human medicine, and a multimodal approach has been suggested for the alleviation of chronic pain in veterinary species. One goal of multimodal therapy is to avoid the 'cellular windup' and heightened sensitivity of the central nervous system to pain sensation seen in response to repetitive noxious stimulus. A key player in this nociceptive processing is the N-methyl-D-aspartate (NMDA) receptor, and NMDA receptor antagonists may offer a benefit, especially in the treatment of chronic pain. Ketamine, tiletamine, dextromethorphan and amantadine possess NMDA antagonist properties, among other actions. Opioid receptors are well known to be involved in pain states, and the descending serotinergic system is known to be one of the body's endogenous 'analgesic' mechanisms. Opioid agonists and opioidergic/monoaminergic drug such as Tramadol have been found to be effective alleviating osteoarthritis pain in humans, as part of a multimodal approach.

Steroidal Antiinflammatory Agents

Corticosteroids: These drugs should be limited in use to those dogs in which no other treatment has worked. There is considerable evidence that steroid therapy speeds up progression of OA, and any positive short-term results are negated by long-term loss of the remaining cartilage. Whenever steroids are used, owners must be aware of the probable detrimental side effects. Remember along with iatrogenic induction of Cushing's syndrome, corticosteroids have been shown to inhibit healing and initiate damage to articular cartilage.

Chondromodulating Agents

These agents are collectively defined as slow-acting drugs in osteoarthritis (SADOA), and are subdivided into symptomatic slow acting drugs (SYSADOA) and disease-modifying osteoarthritis drugs (DMOAD). SYSADOA are agents that claim to improve pain or function with a delay (weeks to months) but may have persistent benefits after treatment discontinuation. DMOADs are products that claim to prevent, reduce or reverse the cartilaginous lesions of OA. These products include compounds such as glucosamine, chondroitin sulfate, polysulfated glycosaminoglycans (PSGAG), Pentosan Polysulfate (PPS), hyaluronan (HA), and different forms of tetracycline analogs.There is little information available verifying treatments that successfully alter the course of pathologic change.


These supplements include Cosequin (glucosamine and purified chondroitin sulfate) and Glycoflex (extract from Perna Canaliculus mussel and sea cucumber), among many others. Many anecdotal reports proclaim high success rates using these products to treat OA, however remember as nutritional supplements these products avoid FDA scrutiny and do not require data to support label claims. There is no current scientific data available that these products are clinically effective in the dog. There is some evidence being generated in vitro which is interesting but it is not directly applicable to the clinical setting. To date, most of the evidence of efficacy used by manufacturers to support their products comes from human clinical trials performed overseas. Several studies involving individual components of Cosequin have demonstrated no significant toxic or detrimental side effects. The product appears to be safe, at least in the short term.


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