Baricitinib
Also known as: Olumiant
Baricitinib is a once-daily tablet that blocks inflammatory signalling inside the cell. In rheumatoid arthritis it can work quickly and well. Like every medicine in this class it carries cautions that matter more for some patients than others, so the choice is always individual.
Calm, careful medication review by a consultant rheumatologist.
What this medicine is
Baricitinib is a targeted synthetic DMARD, usually called a JAK inhibitor. Janus kinases are enzymes inside the cell that pass on messages from inflammatory signals arriving at the cell surface. Baricitinib acts mainly on JAK1 and JAK2, interrupting several inflammatory pathways at once. It is taken by mouth as a once-daily tablet. Because it is cleared largely by the kidneys, the prescriber adjusts the amount according to kidney function and certain interacting medicines, which is one reason I do not publish dose schedules here.
Uses and context
Baricitinib has indications such as rheumatoid arthritis, and depending on the country it may also be approved for conditions including atopic dermatitis, alopecia areata and juvenile idiopathic arthritis. Local approved uses vary, and this list is not exhaustive. It should not be assumed to be approved for adult psoriatic arthritis; where psoriatic arthritis is the diagnosis, other targeted synthetic DMARDs and biologics have the relevant evidence and approvals, and I would choose from those instead. Baricitinib, tofacitinib and upadacitinib are related but distinct medicines and are not interchangeable. It is generally considered when a conventional DMARD such as methotrexate has not given adequate control, or cannot be used, and it can be taken alone or with methotrexate.
How this relates to rheumatology care
Realistic benefit and timing: many patients notice improvement within one to four weeks, with a clearer assessment at about three months, judged on symptoms, joint examination, function and inflammatory markers. Because JAK2 is involved in blood cell production, I keep a particular eye on blood counts, including haemoglobin and platelets. The class cautions apply here too: regulators advise care with blood clots, major cardiovascular events and cancer, particularly in patients over sixty-five, current or former long-term smokers, and people with cardiovascular or cancer risk factors. In those patients I usually favour another class, while in a younger patient without those risks baricitinib can be a very good option. Shingles is also more common with JAK inhibitors. Related reading includes my guides to rheumatoid arthritis and juvenile idiopathic arthritis.
What safety checks may matter
Full blood count before starting and during treatment, watching neutrophils, lymphocytes, haemoglobin and platelets
Liver function tests at baseline and on follow-up
Lipid profile at baseline and rechecked after starting, since cholesterol can rise
Kidney function checked, since baricitinib is cleared by the kidneys and the amount is adjusted accordingly
Tuberculosis screening with chest X-ray and IGRA or Mantoux, plus hepatitis B and C screening before starting
Assessment of age, smoking history, cardiovascular risk, clot risk and cancer history before choosing this class
Vaccination review, with non-live vaccines and shingles vaccination considered before starting where available
Skin checks and age-appropriate cancer screening kept up to date
Side effects and red flags
If you have emergency symptoms such as severe allergic reaction, breathing difficulty, chest pain, stroke-like symptoms, severe abdominal pain, vomiting blood, black stools, sudden vision loss, severe infection symptoms, or severe weakness or confusion, please seek urgent medical care first rather than waiting for a WhatsApp reply.
Calf pain, swelling or tenderness in one leg, which can indicate a clot
Sudden breathlessness, chest pain or coughing blood, which can indicate a clot in the lung
Chest pain, pressure or tightness, or symptoms of stroke such as face droop, arm weakness or slurred speech
Fever, chills, a persistent cough, night sweats or any sign of serious infection
A painful blistering rash in a band, which may be shingles
Severe abdominal pain with fever, which needs urgent assessment
Facial or tongue swelling, or another sign of a severe allergic reaction
Things worth knowing day to day
Infection precautions: pause the tablets during a significant infection or fever and contact me. Report any painful blistering rash promptly, as shingles is more common with this class.
Avoid live vaccines while on baricitinib. Non-live vaccines are encouraged, and shingles vaccination is best considered before starting.
Do not smoke. Smoking adds to both the cardiovascular and the clot risk that already need weighing with this class.
Tell me about any personal or family history of blood clots, heart attack, stroke or cancer, and about hormone treatments or long periods of immobility such as long-haul flights.
Tell any surgeon or dentist that you take baricitinib. It is usually paused around major surgery and restarted once healing is secure and there is no infection.
Common effects include upper respiratory infections, headache, nausea, raised cholesterol, cold sores and mild blood count changes.
Baricitinib must be avoided in pregnancy and breastfeeding, and effective contraception is advised during treatment and for a period afterwards. If you are planning a family, tell me early so we can move to a more suitable option in good time.
Tell me about any new medicine, particularly certain drugs that affect how the kidneys clear baricitinib.
Questions patients often ask me about this medicine
Speak with me
If baricitinib has been suggested for you, or you want to understand where a JAK inhibitor sits among your options, please message my clinic. I will go through the benefits and the cautions in your particular situation.
Other medications used in rheumatology care
This page is for general education only and does not replace medical advice. Please consult a qualified healthcare professional for diagnosis and treatment. Do not start, stop, or change any medicine without advice from your doctor.