Ulipristal: Selective Progesterone Receptor Modulator (SPRM) for Emergency Contraception
Ulipristal is a selective progesterone receptor modulator (SPRM). At the lower dose of 30 mg, it is approved in Europe as ellaOne for emergency contraception after unprotected intercourse or contraceptive failure up to 120 hours. On this page you will find the pillar page for the active ingredient ulipristal in its emergency contraception variant. The salt form ulipristal acetate (UPA) is the only form used in medicines. A detailed separate description of the higher 5 mg dose (Esmya, myoma indication) can be found at /wirkstoff/ulipristalacetat.
ellaOne was approved in the EU in 2009 and has been available without a prescription in German pharmacies since 2015. This makes ulipristal, alongside levonorgestrel, the second pillar of hormonal emergency contraception. The efficacy and longer application window make ulipristal the first choice in many guidelines. Emergency contraception does not replace regular contraception and should be understood as an exception, but it is an important right of reproductive health.
Mechanism of Action
Ulipristal binds with high affinity to the progesterone receptor. There it acts partly agonistically and partly antagonistically depending on the tissue. The main action in emergency contraception is the delay or inhibition of ovulation by suppressing the preovulatory LH surge. Ulipristal remains effective even after the LH surge has begun, which makes it superior to levonorgestrel: the latter only works if the LH peak has not yet occurred.
In addition, ulipristal changes endometrial receptivity, which can make implantation of a potentially fertilized egg cell more difficult. This effect is clinically less relevant for emergency contraception than ovulation delay. Important: Ulipristal is not an abortion pill; it works before implantation and does not terminate an existing pregnancy. This distinction is often not communicated clearly enough in counseling.
Pharmacokinetically, ulipristal acetate is well absorbed orally, with a half-life of approximately 32 hours. It is metabolized via CYP3A4.
Applications
- Emergency contraception (ellaOne, 30 mg): after unprotected intercourse or contraceptive failure up to 120 hours (5 days)
- Symptomatic treatment of uterine fibroids (Esmya, 5 mg, indication restricted): since the EMA requirement in 2020 only in women without alternatives and without pre-existing liver disease; detailed pillar page at Ulipristal Acetate
Dosage and Administration
Emergency contraception: one single tablet of 30 mg ulipristal acetate (ellaOne) as soon as possible, but no later than 120 hours after the risk event. Efficacy is good throughout the time window, but highest in the first 24 hours.
If vomiting occurs within 3 hours of administration: retaking a tablet is recommended. Hormonal contraception afterwards: Ulipristal can temporarily impair the effectiveness of hormonal contraceptives. Until the next period, additional contraception with condoms must be used; hormonal contraception may only be started or resumed 5 days after ulipristal administration.
Breastfeeding: A breastfeeding pause of one week after administration is recommended; during this time, breast milk should be expressed and discarded.
Side Effects
Common: Headache, nausea, abdominal pain, fatigue, dizziness, changes in menstrual bleeding (advanced or delayed by a few days, sometimes heavier), spotting.
Uncommon: Vomiting, diarrhea, acne, hot flushes, mood swings, breast tenderness.
Rare: Allergic reactions; in rare cases, pregnancy complications if emergency contraception fails. High-dose use of ulipristal (5 mg) for fibroids was associated in 2020 with some severe liver damage; this risk is not described with the single dose of 30 mg ellaOne.
Drug Interactions
- Hormonal contraceptives (pill, patch, vaginal ring): Ulipristal can reduce their effectiveness; use condoms in addition for 5 days after ulipristal administration
- Levonorgestrel as emergency contraceptive: do not take in combination; both compete for the progesterone receptor and weaken each other
- CYP3A4 inducers (rifampicin, carbamazepine, phenytoin, St. John's wort, efavirenz): significantly reduce ulipristal effectiveness; for these patients, a copper IUD is preferably recommended as emergency contraception
- Gastric acid blockers (PPI, H2 blockers): marginally reduce absorption, probably not clinically relevant
- Strong CYP3A4 inhibitors (ketoconazole): increase levels, usually not clinically relevant
Special Notes
After administration: the next period may occur earlier or later than expected, with altered intensity. If it occurs more than seven days later than expected, a pregnancy test should be performed to rule out pregnancy.
Pharmacy counseling: ellaOne is available without a prescription in Germany; pharmacy counseling covers administration, interactions with hormonal contraception, behavior in case of vomiting, and the need for a pregnancy test if menstruation is absent.
Repeated use: Ulipristal can be used multiple times in the same cycle, but is not intended for regular contraception. Anyone who repeatedly needs emergency contraception should take advantage of counseling options for regular contraception.
Pregnancy: Ulipristal is contraindicated in existing pregnancy, since it also has progesterone antagonistic effects. If emergency contraception fails and pregnancy occurs, current data do not indicate an increased risk of birth defects; prenatal counseling is still advisable.
You may also be interested in
- Ulipristal Acetate, detailed pillar page (salt form, high-dose Esmya for fibroids)
- Levonorgestrel, alternative emergency contraception up to 72 hours
- Mifepristone, progesterone antagonist with different indication
- Desogestrel, progestin-only pill
- Ethinyl Estradiol, estrogen component in combined pills
Frequently Asked Questions
When should I take ellaOne, when rather the morning-after pill with levonorgestrel?
ellaOne (Ulipristal) works up to 120 hours after the risk event and remains effective even after the LH surge has begun. Levonorgestrel is only approved for up to 72 hours and loses significantly in effectiveness after the LH surge begins. Therefore, ulipristal is the first-choice agent in most guidelines, especially if administration occurs more than 72 hours after the event or if the risk period falls in the late follicular phase.
Is ellaOne an abortion pill?
No. Ulipristal delays or prevents ovulation and can change endometrial receptivity. It works before implantation. An already established pregnancy (implantation of the egg cell in the uterus) is not terminated by ellaOne.
Does emergency contraception harm my fertility?
No. A single dose of ulipristal has no known long-term effects on fertility. However, regular contraception should not be replaced by emergency contraception, because its effectiveness per cycle is lower than that of a regular method.
What should I do if my period does not come?
If the next period occurs more than seven days later than expected, you should do a pregnancy test. Pregnancy despite emergency contraception is rare but possible. If the test is positive, timely medical consultation is advisable.
Sources
- EMA, ellaOne (Ulipristal Acetate 30 mg) EPAR
- DGGG Guideline Contraception and Emergency Contraception
- Gelbe Liste, Ulipristal Active Ingredient Profile
- BfArM, Federal Institute for Drugs and Medical Devices
Legal Notices and Disclaimer
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