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JAK Inhibitor (Janus Kinase 1 and 3 Inhibitor) Pregnancy: Contraindicated — teratogenic in animal studies. Ensure effective contraception in women of childbearing age. Discontinue at least 4 weeks before planned conception.

Tofacitinib

Brand names: Xeljanz

Adult dose

Dose: UC induction: 10mg twice daily for 8 weeks. Maintenance: 5mg twice daily. Continue 10mg BD maintenance in patients with severe disease, prior anti-TNF failure, or inadequate response to 5mg BD.
Route: Oral
Frequency: Twice daily
Max: 10mg twice daily
Oral small-molecule drug — no injections. MHRA/EMA 2023 warning: increased risk of major adverse cardiovascular events (MACE), VTE, malignancy, and serious infections — especially in patients >65 years, smokers, or with cardiovascular risk factors. Avoid in these groups where possible. Screening: TB, hepatitis B, FBC, lipids before starting.

Paediatric dose

Route: N/A
Frequency: N/A
Max: Not licensed in children
Not licensed in patients <18 years for UC. Seek specialist opinion.

Dose adjustments

Renal

Moderate renal impairment (eGFR 30–60): reduce to 5mg twice daily. Severe (eGFR <30): avoid.

Hepatic

Moderate hepatic impairment: reduce to 5mg twice daily. Severe: avoid.

Clinical pearls

  • Oral route advantage: preferred by some patients over injectable biologics. However, risk profile (MACE, VTE, malignancy) has led to restriction in higher-risk patients.
  • ORAL Surveillance study (2021): tofacitinib showed higher rates of MACE and malignancy vs anti-TNF in RA patients — triggered regulatory restrictions. Apply same caution in UC.
  • Herpes zoster reactivation: offer varicella zoster vaccine (Shingrix) before starting if not previously vaccinated. Monitor for shingles during treatment.
  • Lipid monitoring: total cholesterol and LDL increase within 4–8 weeks of starting — monitor and treat if needed.

Contraindications

  • Active serious infection including active TB
  • Severe hepatic impairment
  • Absolute lymphocyte count <500 cells/mm³
  • Haemoglobin <8g/dL
  • Pregnancy and breastfeeding

Side effects

  • Serious infections (bacterial, opportunistic including TB, herpes zoster — reactivation risk)
  • Venous thromboembolism (DVT, PE — class warning for all JAK inhibitors)
  • Major adverse cardiovascular events (MACE — myocardial infarction, stroke)
  • Malignancy (lymphoma, lung cancer)
  • Anaemia, neutropenia
  • Hyperlipidaemia (LDL and HDL increase)
  • Elevated creatinine (usually minor)

Interactions

  • Strong CYP3A4 inhibitors (ketoconazole, clarithromycin): increase tofacitinib levels — reduce dose
  • Moderate CYP3A4 inhibitors + strong CYP2C19 inhibitors (fluconazole): reduce dose to 5mg BD
  • Strong CYP3A4 inducers (rifampicin): reduce tofacitinib efficacy — avoid
  • Live vaccines: contraindicated
  • Immunosuppressants (azathioprine, methotrexate): avoid combination (increased infection risk)

Monitoring

  • FBC (neutrophils, lymphocytes, haemoglobin) at baseline, 4–8 weeks, then every 3 months
  • Lipid profile (baseline, 4–8 weeks after starting)
  • LFTs and renal function (baseline and periodically)
  • TB screening at baseline and annually
  • Blood pressure and cardiovascular risk assessment

Reference: BNFc; BNF 90; NICE TA547 (Tofacitinib for UC); MHRA Drug Safety Update 2023 (JAK inhibitors); ORAL Surveillance Study (Ytterberg et al, NEJM 2022). Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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