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baricitinib

OlumiantJAK inhibitor

Olumiant (baricitinib) is an oral Janus kinase inhibitor from Eli Lilly. By damping JAK-STAT signalling it reduces inflammatory cytokine activity, and is used in rheumatoid arthritis after TNF blockers, in hospitalized adults with severe COVID-19, and in severe alopecia areata.

This page is based on FDA prescribing information and the EMA medicine record for baricitinib, cross-checked with DailyMed and MedlinePlus; the mechanism is explained in plain language, and analogies are used only where they stay accurate.

How it works

Explains what the medicine does in the body, not dosing, side effects, or safety.

An analogy

Cytokines are letters dropped into mailboxes on cell surfaces, and JAK enzymes are the clerks inside who forward each letter to the nucleus. In inflammatory disease the mailbox overflows. Baricitinib suspends the clerks, so even when letters arrive, the orders to inflame never reach the nucleus.

In simple terms

Many inflammatory diseases are driven by cytokines, chemical messages that tell immune cells to stay active. Those messages are relayed inside cells by Janus kinases. Baricitinib blocks JAK1 and JAK2, interrupting the relay. With fewer instructions getting through, inflammation in joints and skin is reduced, and the overactive immune response in severe infections is also calmed.

In depth

Baricitinib is an oral, ATP-competitive inhibitor of JAK1 and JAK2 with selectivity over JAK3 and TYK2. By preventing phosphorylation of STAT transcription factors it suppresses signalling of cytokines including IL-6, interferon-gamma and GM-CSF, reducing production of inflammatory mediators. In rheumatoid arthritis this attenuates synovial inflammation; in severe SARS-CoV-2 infection it blunts the hyperinflammatory cascade implicated in respiratory deterioration.

See it in motion

A schematic animation of the mechanism — simplified for clarity, not drawn to scale.

How baricitinib inhibits JAK1 and JAK2

JAK1 and JAK2baricitinibInflammatory cytokine signalling
  1. Many inflammatory diseases are driven by cytokines, chemical messages that tell immune cells to stay active. Those messages are relayed inside cells by Janus kinases.
  2. Baricitinib is an oral, ATP-competitive inhibitor of JAK1 and JAK2 with selectivity over JAK3 and TYK2.
  3. By preventing phosphorylation of STAT transcription factors it suppresses signalling of cytokines including IL-6, interferon-gamma and GM-CSF, reducing production of inflammatory mediators.
  4. In rheumatoid arthritis this attenuates synovial inflammation; in severe SARS-CoV-2 infection it blunts the hyperinflammatory cascade implicated in respiratory deterioration.
How baricitinib works

Target: Janus kinases 1 and 2 (JAK1/JAK2)

Intracellular kinases that relay signals from many cytokine receptors to the cell nucleus; in inflammatory disease they pass along too many "inflame" messages.

Approved uses

Approved uses differ by country and change over time. Always follow your local prescribing information.

Approved uses in United States

FDA
  • Treatment of adults with moderately to severely active rheumatoid arthritis who have had an inadequate response to one or more tumor necrosis factor (TNF) blockers
  • Treatment of coronavirus disease 2019 (COVID-19) in hospitalized adults requiring supplemental oxygen, non-invasive or invasive mechanical ventilation, or extracorporeal membrane oxygenation (ECMO)
  • Treatment of adults with severe alopecia areata

Approved uses in European Union

EMA
  • Treatment of moderate to severe active rheumatoid arthritis in adults who have responded inadequately to, or who are intolerant to, one or more disease-modifying anti-rheumatic drugs (DMARDs), as monotherapy or in combination with methotrexate
  • Treatment of moderate to severe atopic dermatitis in adults and children from 2 years of age who are candidates for systemic therapy

Official sources

The statements on this page trace back to these records.

  1. Olumiant (baricitinib) — Summary of product characteristics and package leaflet, English version

    European Medicines Agency

  2. DailyMed: Olumiant (baricitinib) label

    DailyMed, U.S. National Library of Medicine

  3. U.S. Food and Drug Administration: baricitinib prescribing information

    U.S. Food and Drug Administration

  4. MedlinePlus: baricitinib

    MedlinePlus, U.S. National Library of Medicine

  5. National Cancer Institute: baricitinib

    National Cancer Institute

This page explains how the medicine works — it isn’t the patient leaflet. For anything that applies to you, read the leaflet that came with your medicine or ask your pharmacist.

MedUnfold provides educational content and is not medical advice. Always follow your local prescribing information and healthcare professional.