What should you know about JAK inhibitors for ulcerative colitis?

Ulcerative colitis causes inflammation in the lining of the bowel. A JAK inhibitor blocks selected signals that help drive this immune response. It is taken by mouth, and the choice depends on your symptoms, previous treatments, medical history and clinician assessment.

Treatment may reduce diarrhoea, rectal bleeding and abdominal pain, but it can also affect infection risk and blood-test results. Your clinician may check your blood count, liver tests, cholesterol and infection history before and during treatment. Do not stop or change the dose without advice.

Take the medicine exactly as prescribed and tell the prescriber about pregnancy, plans for pregnancy, recent infections, blood clots, heart disease, cancer, liver problems and all other medicines. Keep monitoring appointments even when bowel symptoms improve.

Seek advice before receiving a live vaccine. Keep a record of new fever, cough, painful skin changes or unusual symptoms. A GP Consultation can help review ongoing bowel symptoms and arrange appropriate tests.

Contact a clinician promptly for fever, breathlessness, a painful swollen leg, sudden chest pain, severe abdominal pain, persistent vomiting or rapidly worsening diarrhoea. These symptoms need assessment rather than a medication adjustment at home.

Ask why a JAK inhibitor is suitable, when improvement should be reviewed, which blood tests are needed, what to do after a missed dose and which symptoms require urgent help. Ask whether your bowel cancer screening plan needs updating.