The safety of baricitinib in patients with rheumatoid arthritis.

: Despite improvement in disease outcomes and prognosis, a substantial number of patients with rheumatoid arthritis (RA) still require a novel agent for effective treatment. Baricitinib is a targeted synthetic disease-modifying antirheumatic drug (tsDMARDs) that selectively inhibits Janus kinase (JAK1/JAK2), an important enzyme in the pathogenesis of RA.: This paper aimed to evaluate the pharmacodynamics and pharmacokinetics of baricitinib while reviewing its safety and efficacy in the treatment of RA.: Randomized controlled trials of baricitinib showed its efficacy and safety in patients with active RA who were methotrexate (MTX)-naïve or were not adequately responsive to MTX, conventional synthetic DMARDs, or tumor necrosis factor inhibitors. Baricitinib may be suitable in patients who prefer oral therapy and do not have a history of severe renal impairment, recent history of malignancy, or risk factors for adverse events (AEs) such as venous thromboembolism, opportunistic infection, and diverticulitis. Dose adjustment of baricitinib, based on the assessment of patient conditions including their renal function and disease activity, is an important strategy for successful and safe treatment. However, long-term post-marketing surveillance studies with a larger sample size are required to evaluate the overall safety and AEs with low incidence rates in clinical settings.