JAK1 Inhibitor (UC) Pregnancy: Contraindicated during pregnancy - animal studies show reproductive toxicity and filgotinib may cause foetal harm. Women of childbearing potential must use effective contraception during treatment and for at least 1 week after stopping. Breast-feeding: excretion in human milk is unknown and a risk to the infant cannot be excluded - should not be used while breast-feeding.

Filgotinib

Brand names: Jyseleca

Filgotinib is an oral Janus kinase (JAK) inhibitor used to treat moderately to severely active ulcerative colitis in adults with an inadequate response to conventional or biological therapy.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 200 mg

Route: Oral

Frequency: Once daily (ulcerative colitis induction and maintenance)

SPC §4.2 (ulcerative colitis): induction 200 mg once daily; if there is no adequate therapeutic benefit during the initial 10 weeks, a further 12 weeks of induction at 200 mg once daily may give additional symptom relief - discontinue in patients with no therapeutic benefit after 22 weeks. Maintenance 200 mg once daily; in adults at higher risk of VTE, MACE and malignancy the recommended maintenance dose is 100 mg once daily, escalated to 200 mg once daily in case of disease flare. Use the lowest effective dose for long-term treatment. Elderly with ulcerative colitis (65 years and older): 200 mg once daily for induction and 100 mg once daily for maintenance (200 mg on flare); not recommended at 75 years and older (no data). Rheumatoid arthritis (other indication on the same SPC): 200 mg once daily, or 100 mg once daily in adults at increased risk of VTE, MACE and malignancy or aged 65 and over, escalating to 200 mg if disease control is insufficient. Treatment should be initiated by a physician experienced in treating rheumatoid arthritis or ulcerative colitis. Do not initiate, or interrupt treatment, if ANC <1 x 10^9/L, ALC <0.5 x 10^9/L, or Hb <8 g/dL; restart once values recover. Check lipids 12 weeks after initiation. Interrupt treatment if a serious infection develops until it is controlled. Take with or without food; swallow tablets whole. Hepatic impairment: no adjustment in Child-Pugh A or B; not recommended in Child-Pugh C. Paediatric population: safety and efficacy in children under 18 years have not yet been established and no data are available.

Dose adjustments

Renal

No dose adjustment in mild renal impairment (CrCl >=60 mL/min). 100 mg once daily is recommended in moderate or severe renal impairment (CrCl 15 to <60 mL/min). Not recommended in end-stage renal disease (CrCl <15 mL/min) as it has not been studied.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Hypersensitivity to the active substance or to any of the excipients
Active tuberculosis or active serious infections
Pregnancy

Side effects

Urinary tract infection and upper respiratory tract infection (common)
Nausea (common)
Dizziness (common)
Lymphopenia and blood phosphorus decreased (common)
Uncommon: herpes zoster, pneumonia, sepsis, neutropenia, hypercholesterolaemia, vertigo, blood creatine phosphokinase increased

Interactions

Other potent immunosuppressants - ciclosporin, tacrolimus, biologics or other JAK inhibitors: combination not recommended (risk of additive immunosuppression)
(§4.5 was not included in the fetched bundle - the above is from SPC §4.4; verify against the full SPC)

Clinical monograph

How it works

It preferentially inhibits JAK1, blocking signalling of pro-inflammatory cytokines through the JAK-STAT pathway and thereby reducing the immune-mediated mucosal inflammation of ulcerative colitis.

Prescribing in practice

As a JAK inhibitor it carries MHRA-highlighted risks of serious infection, venous thromboembolism, major adverse cardiovascular events and malignancy, so use cautiously and reserve higher-risk patients for when no suitable alternatives exist.
Screen for and treat latent tuberculosis and viral hepatitis before starting, and ensure vaccinations including herpes zoster are up to date as live vaccines are contraindicated during treatment.
Avoid in pregnancy; effective contraception is required during treatment because of potential effects on fertility and the developing fetus.

Monitoring

Monitor full blood count, lipids and liver function, and remain vigilant for signs of infection, thromboembolism and skin malignancy throughout treatment.

Counselling the patient

Report any signs of infection such as fever, cough or persistent sore throat, and any leg swelling, chest pain or breathlessness promptly.
Do not have live vaccines while taking this medicine and tell the team you are on it before any vaccination.

Evidence & guidelines

Filgotinib is recommended by NICE within its marketing authorisation for moderately to severely active ulcerative colitis.

Reference: Feagan et al. Lancet 2021 (SELECTION); MHRA Drug Safety Update 2022 (JAK class); EMA CHMP assessment report filgotinib; Confirm identity and dosing against the manufacturer SPC (eMC) and NICE. Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways