Olumiant, with the active ingredient baricitinib, is a prescription medication primarily used in the treatment of moderate to severe rheumatoid arthritis in adults who have had an inadequate response to one or more tumor necrosis factor (TNF) antagonist therapies. Classified as a Janus kinase (JAK) inhibitor, Olumiant works by interfering with the pathway that leads to inflammation, thereby helping to reduce the symptoms associated with rheumatoid arthritis such as pain, swelling, and stiffness in the joints. It is administered orally, typically once a day, and can be used alone or in combination with other rheumatoid arthritis medications. Like all medications, Olumiant comes with a risk of side effects, and its use must be closely monitored by a healthcare provider.