Psoriatic Arthritis treatments: Janus Kinases (JAK) inhibitor

Upadacitinib is a Janus kinase (JAK) inhibitor and belongs to a group of medicines known as disease-modifying antirheumatic drugs (DMARDs). It is used to treat adults with active psoriatic arthritis when previous treatment with one or more DMARDs has not worked well enough or has not been tolerated.

Upadacitinib can be used on its own or together with methotrexate.

Upadacitinib works by blocking the activity of enzymes called Janus kinases (JAKs). These enzymes help carry signals involved in inflammation. By reducing these signals, upadacitinib can reduce inflammation associated with psoriatic arthritis.

Treatment can help reduce joint pain, stiffness and swelling and may improve physical function and quality of life. It can also improve some of the skin symptoms associated with psoriatic arthritis and can help slow the progression of joint damage.

Who can get it?

Upadacitinib is available on prescription and treatment should be started and supervised by a specialist experienced in treating psoriatic arthritis.

For psoriatic arthritis, it is prescribed for adults whose disease has not responded adequately to, or who cannot tolerate, one or more DMARDs. It can be used alone or in combination with methotrexate.

Because JAK inhibitors are associated with an increased risk of some serious side effects, particular caution is needed in people aged 65 years or over, people who currently smoke or have smoked for a long time, and people with cardiovascular or other risk factors. In these groups, upadacitinib should only be used when there are no suitable alternative treatments.

You will need blood tests before and during treatment. These may be used to check your blood cell counts, cholesterol and other blood fats, and liver function.

You should avoid food and drink containing grapefruit while taking upadacitinib because grapefruit can increase the amount of medicine in your blood and may increase the risk of side effects.

Do not take upadacitinib if you:

• are allergic to upadacitinib or any of the other ingredients
• have active tuberculosis (TB)
• have an active serious infection
• have severe liver problems
• are pregnant.

Your doctor will also check for infections such as TB before treatment is started.

How is it used?

For psoriatic arthritis, the recommended dose is:

15 mg once a day.

• Take the tablet once a day, preferably at the same time each day.
• It can be taken with or without food.
• Swallow the tablet whole with water.
• Do not split, crush or chew the tablet, as this can affect how the medicine is released into your body.

Your doctor may advise you to interrupt treatment if you develop a serious infection. The dose may also need to be adjusted in some people with severe kidney problems.

What are the side effects?

Like all medicines that affect the immune system, upadacitinib can increase the risk of infections. Common infections include infections of the nose and throat, urinary tract infections, herpes simplex and shingles.

Common side effects can include:

• sore throat and other upper respiratory tract infections
• acne
• cough
• fever
• nausea
• headache
• tiredness
• abdominal pain
• urinary tract infection
• influenza
• cold sores
• rash
• increased cholesterol
• increased liver enzymes shown by blood tests
• increased creatine kinase shown by blood tests
• anaemia or changes in white blood cell counts
• weight gain
• inflammation of the hair follicles (folliculitis)
• hives (urticaria).

Other side effects can include increased triglycerides, oral thrush and diverticulitis.

Upadacitinib can rarely cause serious infections. It is also associated with an increased risk of blood clots, major cardiovascular events and some cancers. These risks are particularly important in certain higher-risk patients, including some older people and people with cardiovascular or smoking risk factors.

Seek urgent medical advice if you develop symptoms that could indicate a serious infection, blood clot or cardiovascular problem, such as persistent fever, severe breathlessness, chest pain, or painful swelling of a leg.

Your doctor will monitor you during treatment and may stop or interrupt treatment if serious side effects occur.

Marketed by

Upadacitinib is known commercially as Rinvoq® and is marketed in the UK by AbbVie Ltd.

Reviewed: August 2026
Version ID: 2/UPA/PAT/08/26

Tofacitinib is a medicine known as a Janus kinase (JAK) inhibitor. It belongs to a group of medicines called disease-modifying antirheumatic drugs (DMARDs). It is used to treat active psoriatic arthritis in adults whose disease has not responded adequately to previous DMARD treatment or who cannot tolerate these medicines.

Tofacitinib works by blocking the activity of enzymes called Janus kinases (JAKs). These enzymes are involved in sending signals that promote inflammation. By reducing these signals, tofacitinib can help reduce inflammation, pain and swelling in the joints associated with psoriatic arthritis.

Who can get it?

Tofacitinib is available on prescription and treatment should be started and supervised by a specialist experienced in treating psoriatic arthritis.

For psoriatic arthritis, tofacitinib can be used with methotrexate or on its own if methotrexate is not tolerated or is considered inappropriate.

Because JAK inhibitors are associated with increased risks of serious infections, cardiovascular events, blood clots and some cancers, particular caution is needed in people aged 65 or over, people who currently or previously smoked for a long time, and people with cardiovascular or malignancy risk factors. In these groups, tofacitinib should only be used when there are no suitable alternative treatments.

Tofacitinib should not be used in people with an allergy to the medicine, active tuberculosis, serious infection such as sepsis, opportunistic infection, severe liver impairment, or during pregnancy or breastfeeding.

How is it used?

Tofacitinib is taken by mouth and can be taken with or without food.

For adults with psoriatic arthritis, the usual dose is:

5 mg twice a day.

The dose may need to be reduced in certain circumstances, including some people with severe kidney impairment or moderate liver impairment. Your doctor will decide whether a reduced dose is necessary.

Tofacitinib should not be taken with certain other medicines that can excessively suppress the immune system, including some biological treatments and potent immunosuppressants.

What are the side effects?

Tofacitinib affects the immune system and can increase the risk of infections. Some infections can be serious. Treatment should be interrupted if a serious infection develops until the infection is controlled.

Possible side effects include:

• Upper respiratory tract infections
• Headache
• Diarrhoea
• Nausea
• High blood pressure
• Increased cholesterol and other changes in blood fats
• Changes in blood cell counts, including anaemia or reduced white blood cells
• Increased risk of infections
• Increased risk of shingles
• Liver enzyme abnormalities

Less commonly, more serious problems can occur, including serious infections, blood clots, major cardiovascular events such as heart attack, and certain cancers. The risk of some of these problems is particularly important in older people and those with cardiovascular, smoking or cancer risk factors.

Tell your doctor urgently if you develop symptoms of a serious infection, unexplained chest pain, sudden breathlessness, swelling or pain in a leg, or other symptoms that could indicate a blood clot or cardiovascular problem.

Before and during treatment, your healthcare team will carry out appropriate checks, which may include blood tests and monitoring for infections, liver abnormalities, changes in blood counts and cholesterol.

Marketed by

Tofacitinib is known commercially as Xeljanz® and is marketed in the UK by Pfizer.

Reviewed: August 2026
Version ID: 2/TOF/PTA/08/26