Sphingosine-1-phosphate receptor modulator Pregnancy: Based on animal findings, may cause foetal harm when given to a pregnant woman; available human pregnancy data are insufficient to identify a drug-associated risk. Animal reproduction studies showed embryolethality and foetal malformations in rats and rabbits at maternal exposures 5-6 times the maximum recommended human dose. A pregnancy exposure registry monitors outcomes (US labelling).

Etrasimod

Brand names: Velsipity

Etrasimod is an oral sphingosine 1-phosphate (S1P) receptor modulator used to treat moderately to severely active ulcerative colitis in adults.

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: 2 mg

Route: Oral

Frequency: Once daily

US prescribing information (VELSIPITY) §2.2: recommended dosage 2 mg orally once daily; swallow the tablet whole, with or without food. If a dose is missed, take it at the next scheduled time - do not double the next dose. No UK SPC posology was available in the fetched bundle, so the UK dose and licensed indication wording must be confirmed against the UK SPC. Assessments required before the first dose (§2.1): recent complete blood count including lymphocyte count; ECG to detect pre-existing conduction abnormalities (cardiology advice in certain pre-existing conditions); recent transaminase and bilirubin levels; baseline fundus/macula evaluation; skin examination; review of drugs that slow heart rate or AV conduction and of prior/current anti-neoplastic, immune-modulating or non-corticosteroid immunosuppressive therapy; test for varicella zoster antibodies if no confirmed history or documented vaccination and vaccinate antibody-negative patients beforehand (live attenuated vaccines at least 4 weeks before starting). Paediatric use: safety and effectiveness in paediatric patients have not been established.

Dose auto-extracted from US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Myocardial infarction, unstable angina, stroke, TIA, decompensated heart failure requiring hospitalisation, or Class III/IV heart failure in the last 6 months
History or presence of Mobitz type II second-degree or third-degree AV block, sick sinus syndrome, or sino-atrial block, unless the patient has a functioning pacemaker

Side effects

Headache (incidence >=5%)
Elevated liver tests (incidence >=5%)
Dizziness (incidence >=5%)
Infections, including serious infections
Bradyarrhythmia and atrioventricular conduction delays
Macular oedema; increased blood pressure

Interactions

Metabolised primarily by CYP2C8, CYP2C9 and CYP3A4 - moderate to strong inhibitors or inducers of these enzymes can change exposure (effect of combinations affecting two or more pathways is unknown)
Class Ia (e.g. quinidine, procainamide) and Class III (e.g. amiodarone, sotalol) anti-arrhythmics and other QT-prolonging drugs: seek cardiologist advice before initiating - additive heart-rate effect may increase risk of QT prolongation and torsades de pointes
Drugs that slow heart rate or AV conduction: consider cardiology consultation (transient heart-rate decrease and AV conduction delays occur on initiation)
Live attenuated vaccines: avoid during and for up to 5 weeks after treatment

Clinical monograph

How it works

It selectively modulates S1P receptor subtypes, causing retention of lymphocytes in lymphoid tissue and so reducing the circulating lymphocytes available to infiltrate the inflamed colon.

Prescribing in practice

Before starting, assess cardiac status, ophthalmic and infection risk because S1P modulators can cause bradycardia and atrioventricular conduction delay at initiation, macular oedema, and increased risk of infection.
Check full blood count, liver function and varicella zoster immunity, and ensure vaccinations are up to date before treatment, avoiding live vaccines during and for a period after therapy.
It is contraindicated in pregnancy and effective contraception is required, as S1P modulators are associated with a risk of fetal harm.

Monitoring

Monitor for signs of infection, perform liver function tests, and arrange ophthalmic assessment in patients at higher risk of macular oedema, with cardiac monitoring as advised at initiation.

Counselling the patient

Use reliable contraception throughout treatment and tell your doctor if you might be pregnant.
Report any visual disturbance, signs of infection or breathlessness.
Keep your vaccinations up to date and avoid live vaccines.

Evidence & guidelines

Its efficacy in ulcerative colitis is supported by randomised placebo-controlled trials and it has been appraised for NHS use by NICE.

Reference: NICE TA969; SmPC; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). 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.

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