Does oral cannabidiol oil in adjunct to pain medications help reduce pain and improve locomotion in dogs with osteoarthritis?

PICO question: In dogs with osteoarthritis (OA), does the oral supplementation of cannabidiol (CBD) oil, compared to conventional treatment alone, improve treatment outcomes of reducing pain and improving locomotion? Clinical bottom line: Category of research: Treatment. Number and type of study designs reviewed: Four papers were critically reviewed. Two of the studies were prospective, randomised, placebo-controlled, double-blind, cross-over clinical trials. One trial was a prospective clinical trial. One study was a prospective, randomised, controlled, clinical trial. Strength of evidence: Weak. Outcomes reported: The analgesic effect of CBD oil supplementation on dogs with OA, as assessed by different parameters. These parameters included pain scoring systems (Canine Brief Pain Inventory (CBPI): comprised of the Pain Severity Score and Pain Interference Score (PIS), Liverpool Osteoarthritis in Dogs (LOAD), and veterinarian assessment), activity assessments (Hudson activity scale, Activities of Daily Living (ADLs): based on Cincinnati Orthopaedic Disability Index (CODI), informal gait analysis, and objective gait analysis), and Quality of Life Index (QoL). Conclusion: CBD oil oral supplementation displayed a significant effect of extra pain relief on top of conventional treatment of canine OA in the clinical trials based on subjective pain assessments. However, the only study that evaluated pain and activity using objective measurements did not show significant improvements between treatment groups; therefore, the evidence supporting its use as an adjuvant to conventional therapy remains weak. Further studies utilising objective measurements are needed to improve the strength of the supporting evidence for a general use of CBD oil as additional analgesia for dogs with OA.