What is baricitinib?

Baricitinib, also known as Olumiant, is used to treat rheumatoid arthritis. It's a type of drug known as a Janus kinase JAK inhibitor. It works by blocking the action of Janus kinase enzymes, which are involved in the inflammation that causes the symptoms of rheumatoid arthritis.

Baricitinib can relieve the symptoms of pain, stiffness and swelling in your joints and slow the joint damage that rheumatoid arthritis can cause. Most people who benefit from this treatment will notice some improvement within the first 12 weeks of treatment.

Is baricitinib suitable for me?

Baricitinib can be prescribed by a consultant rheumatologist for adults with rheumatoid arthritis. It can be used alone or with other disease-modifying anti-rheumatic drugs (DMARDs) such as methotrexate. 

You won't be given baricitinib if you haven't tried other treatments appropriate for your condition first.

Baricitinib is not recommended if you're pregnant, planning to become pregnant or breastfeeding. Your doctor may decide not to prescribe baricitinib if you've had or have any of the following:

  • an active infection
  • repeated or serious previous infections
  • shingles
  • disease of the lungs, liver or kidneys
  • heart problems, high blood pressure, high cholesterol, or blood clots (deep vein thrombosis or pulmonary embolism)
  • cancer
  • very low white or red blood cell count.

You'll have blood tests before treatment starts to assess your condition and to check whether the drug is suitable for you. You'll also need these tests while you're taking baricitinib.

Your doctor will need to check if you’ve previously been exposed to tuberculosis (TB). Even if you don’t have symptoms, the bacteria that cause TB may still be present in the body, and you may need a course of treatment to deal with this before starting baricitinib.

If you've previously had hepatitis you may need regular checks for this as baricitinib may increase the risk of the hepatitis coming back.

When and how do I take baricitinib?

Baricitinib is taken as a tablet once a day. In some circumstances, such as if you're over 75 or if you've had repeated infections, your doctor may decide to reduce the standard dose. 

If you take more than the recommended dose by mistake, contact your doctor straight away. If you miss a dose, carry on with the usual dose the next day – don't double it.

If you haven't noticed any improvement in your symptoms after six months, your doctor may decide to stop the baricitinib treatment.

Because it's a long-term treatment, it's important to keep taking baricitinib unless you have severe side effects, even if it doesn't seem to be working at first. You should still keep taking it even when your symptoms improve, to help keep your condition under control.

Possible risks and side effects

Like any medicine, baricitinib can sometimes cause side effects but many people won't have any problems. You should speak to your rheumatology team about any side effects you have.

You may feel sick, known as nausea, in the first two weeks after starting baricitinib, but this often improves with time.

Because baricitinib affects your immune system, it can make you more likely to pick up infections. These are not usually serious and include throat, nose and chest infections, cold sores, urinary tract infections and stomach upsets.

Some people may have more serious infections including shingles, skin infections, known as cellulitis, and in rare cases hepatitis or tuberculosis.

Tell your doctor or rheumatology nurse straight away if you develop any signs of infection such as a sore throat or persistent cough, fever or chills, or any other new symptoms that concern you. If any of these symptoms are severe, you should stop taking baricitinib and see your doctor straight away.

You should also see your doctor if you develop chickenpox or shingles or come into contact with someone who has chickenpox or shingles. You may need treatment, and you may need to stop taking baricitinib until you’re better.

Some people who take baricitinib may have a reduced white blood cell count, raised cholesterol or raised levels of liver enzymes. These problems are usually mild, but your rheumatology team will arrange regular blood checks while you’re taking baricitinib as a precaution.

If your red or white blood cell count gets too low, your treatment may be stopped until it improves.

It’s possible that baricitinib may increase the risk of blood clots, called deep vein thrombosis.

These can sometimes move to the lungs, which is called pulmonary embolism. The risk is likely to be greater if you've had blood clots before. You should seek urgent medical care if you develop painful swelling of the legs, chest pains or breathlessness.

Tips to reduce your risk of infection

  • Try to avoid close contact with people you know have an infection.
  • Wash your hands regularly and carry around a small bottle of antibacterial hand gel.
  • Keep your mouth clean by brushing your teeth regularly.
  • Stop smoking if you're a smoker.
  • Make sure your food is stored and prepared properly.
  • Try to keep your house clean and hygienic, especially the kitchen, bathrooms and toilets.

Effects on other treatment

You'll probably be taking methotrexate as well as baricitinib. However, some drugs may interact with baricitinib. Check with your doctor before starting any new medicines and remember to mention you're on baricitinib if you're treated by anyone other than your usual rheumatology team.

You can carry on taking non-steroidal anti-inflammatory drugs (NSAIDs) or painkillers, if needed, unless your doctor advises otherwise.

Don't take over-the-counter or herbal medicines without discussing it first with your rheumatology team.


It's best to discuss vaccinations, including any you may need if you're planning to travel abroad, with your rheumatology team. If possible, it's best to have any vaccinations you may need before starting baricitinib.

It's generally recommended that people on baricitinib avoid live vaccines. These include measles, mumps and rubella (MMR), tuberculosis (BCG) and yellow fever.

The Zostavax shingles vaccine is a live vaccine and isn’t recommended for people who are on baricitinib. However, a non-live shingles vaccine (Shingrix) is available so you may be able to have this instead.

Pneumococcal vaccines, which help to protect against pneumonia, and yearly flu vaccines – except the nasal flu vaccine – are fine and are usually recommended.

Having an operation

If you're thinking about having surgery, talk this over with your healthcare team. They may advise you to stop baricitinib for a time before and after surgery.


There's no known interaction between baricitinib and alcohol, so it’s fine to have a drink if you’re taking this medication.

Government guidelines say both men and women should have no more than 14 units of alcohol a week. You should try to spread these out evenly throughout the course of the week. This is equivalent to about six glasses of wine or six pints of beer.

You can find out more about units of alcohol at

Fertility, pregnancy and breastfeeding

At present, we know very little about the effects of baricitinib in pregnancy. To be on the safe side, baricitinib isn’t recommended if you're pregnant or planning a pregnancy. If you could become pregnant, you should use effective contraception while being treated with baricitinib and for at least a week after stopping the treatment.

It's not yet known whether baricitinib passes into breast milk so you should talk to your rheumatology team if you’re thinking of breastfeeding.

There's no information currently available about whether baricitinib might affect male or female fertility.