A JAK inhibitor tablet
Tofacitinib
An oral JAK inhibitor that calms an overactive immune system in rheumatoid arthritis and some other inflammatory conditions.
What is Tofacitinib?
Tofacitinib is a tablet from a group of medicines called JAK inhibitors, used for rheumatoid arthritis and some other inflammatory conditions when standard treatments have not controlled them. It works by damping down chemical signals inside immune cells that drive inflammation, which can ease joint pain, swelling and stiffness. Because it lowers part of the immune response, the main concern is a higher risk of infections, including shingles, and there are cautions about blood clots and heart problems, especially in older people who smoke. Before starting, you are usually screened for infections such as tuberculosis and hepatitis, and you have regular blood tests while taking it. Always report fever, a new rash or signs of infection promptly.
Education and reference only. This is a plain-language guide to Tofacitinib — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Tofacitinib is one of the newer targeted medicines for inflammatory disease, taken by mouth as a tablet. It belongs to a class called JAK inhibitors, which act inside immune cells rather than on the surface. In the UK it is used mainly for moderate to severe rheumatoid arthritis, and in some people for other inflammatory conditions, usually after other disease-modifying treatments have not worked well enough. It is a long-term treatment that needs careful monitoring.
How it works
Inflammation in conditions like rheumatoid arthritis is driven by messenger chemicals that switch immune cells on through enzymes called Janus kinases (JAKs). Tofacitinib blocks these enzymes, so the inflammatory signals are turned down and joint pain, swelling and stiffness can settle. Because the same pathways are part of normal immune defence, dialling them down also makes infections more likely, which is the trade-off behind its main cautions.
Company & origin
Originated / developed by: Pfizer.
An oral JAK inhibitor used in the UK for rheumatoid arthritis and certain other inflammatory conditions when other treatments have not worked well enough.
What it treats
Conditions Tofacitinib is used for
Practical use
How to take Tofacitinib
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Take the tablets regularly as prescribed, with or without food, and try not to miss doses.
- Make sure you have completed the screening tests, such as for tuberculosis and hepatitis, before you start.
- Keep up with your blood test appointments, as these check your blood counts, liver and cholesterol.
- Tell your team promptly about any fever, sore throat, cough, new rash or a painful blistering rash that could be shingles.
- Seek urgent help for swelling or pain in a leg, or sudden breathlessness or chest pain, which can be signs of a clot.
- Avoid live vaccines and check with your team before any vaccination or planned surgery.
Weighing it up
Advantages & disadvantages of Tofacitinib
Advantages
- Taken as a tablet, so it avoids the injections needed for some other advanced arthritis treatments.
- Can work quickly to reduce joint pain, swelling and stiffness when other treatments have not.
- Offers another option for people whose inflammation is not controlled by standard disease-modifying medicines.
Disadvantages
- Increases the risk of infections, including shingles, because it lowers part of the immune response.
- Carries cautions about blood clots and heart problems, particularly in older smokers and those with risk factors.
- Needs screening before starting and ongoing blood tests, and is not suitable in pregnancy.
Practical use
Good to know
The dominant safety message is infection risk: because tofacitinib quietens the immune system, ordinary infections can be more frequent or more serious, and shingles is notably more common, so any fever, sore throat, cough or new rash should be reported. There are also important cautions about blood clots in the legs or lungs and about heart problems, which is why it is used carefully in older people, smokers and those with heart or clotting risk factors. Before starting you are screened for hidden infections such as tuberculosis and hepatitis, and you have blood tests for your blood counts, liver and cholesterol both before and during treatment. Live vaccines are generally avoided, and it is best to be up to date with recommended vaccinations beforehand. It is not used in pregnancy and reliable contraception is advised.
Who should not take it / use with caution
- People with a serious active infection, including active tuberculosis, should not start it until treated.
- It is avoided in pregnancy and breastfeeding, and reliable contraception is advised during treatment.
- Used with great caution or avoided in those at higher risk of blood clots or heart disease, such as older smokers.
Monitoring
- Screening for tuberculosis, hepatitis and other infections before starting.
- Regular blood tests for blood counts, liver function and cholesterol during treatment.
- Watching for signs of infection, shingles, blood clots and heart symptoms throughout.
Side effects
- Infections such as colds, chest and urinary infections, and an increased risk of shingles.
- Headache, raised cholesterol and changes in blood counts and liver tests seen on monitoring.
- Rarely, blood clots in the legs or lungs, or more serious heart or infection problems.
Key interactions
- Combining it with other strong immune-suppressing medicines further raises the infection risk.
- Some antifungal and other medicines change its levels in the body, so doses may need adjusting.
- Live vaccines should be avoided, and other medicines that affect the immune system need careful review.
Available as: Tablets, and an oral liquid in some settings, taken by mouth.
Answers
Tofacitinib: frequently asked questions
Why do I need tests before starting tofacitinib?
Because it lowers part of the immune response, you are screened for hidden infections such as tuberculosis and hepatitis, and have baseline blood tests, to make starting it as safe as possible.
Does it increase my risk of shingles?
Yes, shingles is more common with this medicine; report any painful, blistering rash promptly, as early treatment helps.
What should I watch out for while taking it?
Report fevers or signs of infection, and seek urgent help for leg swelling and pain or sudden breathlessness and chest pain, which can signal a blood clot.
Can I have my usual vaccinations?
Live vaccines are generally avoided; ideally you are up to date before starting, and your team can advise on which vaccines are safe.
Is it safe in pregnancy?
No, it is not used in pregnancy, and reliable contraception is advised during treatment; discuss any plans with your team.
The wider class
About JAK inhibitors
Tofacitinib belongs to the jak inhibitors class. For how the class as a whole works, its shared safety principles and monitoring, see the full guide.
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Authoritative sources
- BNF
- NICE CKS
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