There are numerous clinical trials of RA patients testing the efficacy of TNF inhibitors (infliximab, adalimumab, golimumab, and certolizumab) and anti-IL-6 (tocilizumab) [90], alone or in combination with other drugs such as methotrexate [101,102]; the results show some overall improvement of the disease, as these drugs provide rapid symptom relief by decreasing inflammation and improving other complications associated with RA (fatigue, sleep, and mood disorders), but there are few studies that specifically focus on evaluating pain (see Table 3). This evidence concerns the gene TNF and rheumatoid arthritis.