Background
Osteoarthritis (OA), a slowly progressive, degenerative joint disease characterized by whole-joint structural changes, is common in dogs and cats. Radiographic evidence of OA has been seen in ≈35% to 60% of dogs and 60% to 90% in cats,1-7 although only a subset show clinical signs. The resulting clinical signs (eg, decreased physical activity, lameness) and loss of joint function may affect quality of life.
OA management continues to evolve. Understanding how therapies differ in mechanism, onset, and safety is essential for tailoring treatment to each patient. Detailed information on agent selection and use is available through Plumbs.com.
Treatment Options
Multimodal management of OA is recommended; medical treatment may include analgesics, joint supplements, and nutritional supplements.
Analgesics
NSAIDs
NSAIDs are excellent analgesics that typically have an onset of effect within a few hours to several days. Many NSAIDS are used in veterinary medicine, and several (eg, carprofen, deracoxib, firocoxib, grapiprant, meloxicam) have been approved for acute and/or chronic use in dogs; however, adverse effects severely restrict utility in cats, with only robenacoxib and meloxicam providing proven long-term safety and efficacy.
NSAIDs have a well-characterized adverse effect profile that includes GI erosions/ulceration, hepatotoxicity, and acute kidney injury.
Anti-Nerve Growth Factor Monoclonal Antibodies
Anti-nerve growth factor (anti-NGF) monoclonal antibodies (eg, bedinvetmab, frunevetmab) are species-specific treatment options administered via SC injection; onset of effect is typically delayed by several weeks.
The safety profile of anti-NGF monoclonal antibodies continues to emerge, and clinical experience with bedinvetmab has recognized ataxia, anorexia, and lethargy as common adverse effects.8
Acetaminophen
Acetaminophen is effective for humans with OA. Although data in veterinary medicine are lacking, this drug may be considered for OA management in dogs. Acetaminophen must never be used in cats, as severe methemoglobinemia, hematuria, and fatal icterus (if untreated) will result.
Amantadine
Amantadine has demonstrated efficacy in dogs with OA and previous treatment with meloxicam.9 Amantadine should be used with caution in patients with hepatic disease, congestive heart failure, seizure disorders, or untreated angle-closure glaucoma.
Gabapentin
Gabapentin has not been investigated for management of OA in dogs and cats, but has been noted anecdotally to have some utility. Sedation and ataxia are the most common adverse effects. In dogs, only gabapentin solutions that do not contain xylitol should be used.
Joint Supplements
Polysulfated glycosaminoglycan (PSGAG) is an injectable agent approved for use in dogs; onset of effect occurs over several weeks. PSGAG is structurally related to heparin and has been associated with abnormal bleeding and therefore should not be used in dogs with bleeding disorders.10
Nutritional Supplements
Supplements like cannabidiol, glucosamine/chondroitin, and omega fatty acids typically have a gradual onset of effect when used as adjunctive OA treatments.11-18 Cannabidiol has been associated with elevated liver enzymes,19,20 but the clinical relevance of this finding remains uncertain.