Treatments for Inflammatory Arthritis: Potential But Unproven Role of Topical Copaiba

Traditional medicines for inflammatory arthritis (IA) include nonsteroidal anti-inflammatory drugs (NSAIDs) and cyclooxygenase-2 inhibitors (COXIBs), which have variable clinical benefits and serious side effects. In large-scale randomized, controlled trials (RCTs) in IA, they have demonstrated significant decreases in pain and inflammation but also significant increases in gastrointestinal symptoms, serious bleeding, and cardiovascular events. Copaiba, an essential oil used topically, has potential but unproven benefits, with few to no side effects. Basic research supports its mechanisms of benefit, but human data are sparse and include 1 case series and 1 small RCT examining its benefits for another inflammatory condition, not IA. Providing effective and safe pain relief for patients with IA presents clinical, public health, and research challenges. The clinical challenge is to maximize the benefits of treatment and minimize its risks. Sales of copaiba are increasing and may continue to do so even in the absence of reliable evidence from RCTs, providing a public health challenge. Thus, the research challenge is to test topical copaiba versus a placebo for IA patients against a background of usual care in RCTs of sufficient size, dose, and duration. If such trials show positive results, a logical next step might be head-to-head comparisons against NSAIDs and COXIBs. Evidence from RCTs may support more widespread use or, to paraphrase Huxley, conclude that copaiba is yet another beautiful hypothesis slain by ugly facts.