Effects of Janus Kinase Inhibitors on Rheumatoid Arthritis Pain: Clinical Evidence and Mechanistic Pathways

Pain remains one of the most burdensome symptoms in rheumatoid arthritis (RA), often persisting despite inflammatory remission and profoundly impairing quality of life. This review aimed to evaluate the clinical efficacy and mechanistic pathways by which Janus kinase (JAK) inhibitors alleviate RA-related pain. Evidence from randomized clinical trials demonstrates that JAK inhibitors have demonstrated rapid and significant pain relief, often exceeding that of methotrexate or biologic DMARDs. Improvements in patient-reported pain scores seem to typically emerge within 1–2 weeks and are sustained over time. Beyond anti-inflammatory effects, JAK inhibitors modulate central sensitization and nociceptive signaling by attenuating IL-6 and GM-CSF activity, reducing astrocyte and microglial activation, and downregulating nociceptor excitability in dorsal root ganglia and spinal pathways. Preclinical models further suggest that JAK inhibition interrupts neuroimmune feedback loops critical to chronic pain maintenance. Comparative and network meta-analyses consistently position JAK inhibitors among the most effective agents for pain control in RA. However, individual variability in response, partly due to differential JAK-STAT activation and cytokine receptor uncoupling, underscores the need for biomarker-guided treatment approaches. JAK inhibitors represent a mechanistically distinct and clinically impactful class of therapies that target both inflammatory and non-inflammatory pain in RA. Their integration into personalized pain management strategies offers a promising path to address one of RA’s most persistent unmet needs.