Selective Progesterone Receptor Modulator (SPRM) Pregnancy: CONTRAINDICATED — may cause pregnancy loss at fibroid dose; EC dose: evidence suggests no harm if pregnancy occurs, but use should be avoided

Ulipristal Acetate

Brand names: Esmya (fibroids), EllaOne (emergency contraception)

Adult dose

Dose: Fibroids: 5 mg once daily for up to 8 weeks pre-operatively; Emergency contraception: 30 mg single dose

Route: Oral

Frequency: Once daily (fibroids) or single dose (EC)

Max: 5 mg/day (fibroids); 30 mg single dose (EC)

Fibroids: start during first week of menstrual cycle; EC: take within 120 hours (5 days) of unprotected intercourse — effective up to 120h vs levonorgestrel 72h

Paediatric dose

Dose: Not applicable N/A/kg

Route: N/A

Frequency: N/A

Max: N/A

EC licensed from 16 years; fibroids indication for adults only

Dose adjustments

Renal

No dose adjustment required

Hepatic

CONTRAINDICATED for fibroid indication in any hepatic impairment — MHRA 2020 liver injury restriction; EC single dose acceptable if no alternative

Paediatric weight-based calculator

Patient weight (kg)

EC licensed from 16 years; fibroids indication for adults only

Clinical pearls

MHRA 2020: serious liver injury (including liver failure requiring transplant) reported with Esmya — fibroid indication now restricted: LFTs must be normal before starting, monthly monitoring during treatment, and only 1 treatment course is now recommended; manufacturers withdrew application for repeated courses
PAEC (progesterone receptor modulator-associated endometrial changes): distinct endometrial appearance on biopsy that can be mistaken for hyperplasia by pathologists unfamiliar with the pattern — always inform pathologist of ulipristal use
EllaOne is superior to levonorgestrel EC up to 120 hours — maintains efficacy 96-120h when levonorgestrel is not recommended; consider ulipristal as first-line EC particularly if presenting >72h post-intercourse
Mechanism of EC: delays or inhibits ovulation even after LH surge has begun — this is distinct from any post-fertilisation mechanism; no evidence of abortifacient effect at EC dose
Fibroid preoperative use: reduces fibroid volume by ~50% and achieves amenorrhoea in most patients — allows correction of anaemia before surgery and reduces intraoperative blood loss

Contraindications

Hepatic impairment (fibroid use)
Genital bleeding of unknown cause
Uterine/cervical/ovarian malignancy
Asthma not controlled by glucocorticoids
Pregnancy
Breastfeeding (EC dose)

Side effects

Amenorrhoea/irregular bleeding
Hot flushes
Headache
Nausea
Hepatotoxicity (serious — fibroid indication)
Endometrial thickening (PAEC — progesterone receptor modulator-associated endometrial changes, benign)

Interactions

Strong CYP3A4 inducers (rifampicin, carbamazepine) — reduce ulipristal levels; EC may be less effective
Progestogens — may antagonise EC effect; avoid progestogen-containing contraceptives within 5 days of EC
Hormonal contraception — avoid combined use

Monitoring

LFTs (baseline, then monthly during fibroid treatment)
Endometrial assessment (if bleeding irregularities persist)
Pregnancy test before fibroid treatment

Reference: BNFc; BNF 90; MHRA Drug Safety Update (2020) — Esmya liver injury; PEARL trials I-IV (Donnez et al. NEJM 2012); NICE TA519; SPC Esmya; SPC EllaOne. Verify against your local formulary and the latest BNF before prescribing.

Curated clinical cross-links plus same-class fallbacks.

Calculators