Possible synergic action of non-steroidal anti-inflammatory drugs and glucosamine sulfate for the treatment of knee osteoarthritis: a scoping review

Background: Several studies have reported that glucosamine sulfate (GS) can improve knee osteoarthritis (OA) symptomatology. In parallel, the disease-modifying effects of non-steroidal anti-inflammatory drugs (NSAIDs) in knee OA have also been investigated. However, limited literature has reported the combined effect of GS and NSAIDs. The aim of this scoping review is to describe the scope and volume of the literature investigating the potential benefits and synergistic effect of a combination of GS and NSAIDs in patients with knee OA. Methods: PubMed and Embase were searched for studies published from inception through April 2022, evaluating the effects of the combination of GS and NSAIDs in OA patients, versus either treatment alone. Data are reported narratively. Results: Five studies were included in this review; 4 were randomized control trials and one was a prospective observational study. The duration of combination treatment was 6 to 12 weeks. The combination was compared to celecoxib in 2 studies, meloxicam in 1, etoricoxib in 1, and a conventional NSAID in 1 (ibuprofen or piroxicam). All 5 studies reported that in patients with knee OA, the combination of GS plus NSAID yielded a significantly greater benefit than single-agent therapy, in terms of outcomes including pain reduction, function, joint stiffness, and markers of inflammatory activity and cartilage degradation. Conclusion: The 5 studies included in this scoping review all report a significantly greater clinical benefit with a combination of GS plus NSAID compared to either treatment alone. The evidence supports efficacy in reducing pain, improving function, and possibly regulating joint damage. However, further randomized trials with larger sample sizes are warranted to confirm these findings.