Baricitinib, sold under the brand name Olumiant among others, is an immunomodulatory medication used for the treatment of rheumatoid arthritis, alopecia areata, and COVID-19. It acts as an inhibitor of janus kinase (JAK), blocking the subtypes JAK1 and JAK2.

Baricitinib is approved for medical use in the European Union and in the United States.

In February 2017, baricitinib was approved for use in the European Union as a second-line therapy for moderate to severe active rheumatoid arthritis in adults, either alone or in combination with methotrexate.

In May 2018, the US Food and Drug Administration (FDA) approved baricitinib for the treatment of adults with moderately to severely active rheumatoid arthritis who have had an inadequate response to one or more TNF antagonist therapies.

In May 2022, the FDA approved baricitinib for the treatment of COVID-19 in hospitalized adults requiring supplemental oxygen, non-invasive or invasive mechanical ventilation, or extracorporeal membrane oxygenation (ECMO). Baricitinib is the first immunomodulatory treatment for COVID-19 to receive FDA approval.

In the United States, baricitinib is authorized under an emergency use authorization (EUA) for the treatment of COVID-19 in hospitalized people aged 2 to less than 18 years of age who require supplemental oxygen, non-invasive or invasive mechanical ventilation, or extracorporeal membrane oxygenation.

In June 2022, the FDA authorized baricitinib for the treatment of severe alopecia areata.

During pregnancy, the use of baricitinib is contraindicated.