The 'morning after' pill ellaOne
Ulipristal
An emergency 'morning after' pill that can be used later after unprotected sex than the older levonorgestrel one.
What is Ulipristal?
Ulipristal, sold as ellaOne, is an emergency contraceptive — a 'morning after' pill taken as a single dose after unprotected sex or when regular contraception has failed. It can be taken a little later after sex than the older levonorgestrel pill, but the sooner it is taken the better. It works by delaying the release of an egg. It is less effective if you are already using hormonal contraception or have taken enzyme-inducing medicines, and breastfeeding is paused for a short time afterwards.
Education and reference only. This is a plain-language guide to Ulipristal — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Ulipristal is an emergency contraceptive used after unprotected sex, a split condom or a missed run of pills, to reduce the chance of pregnancy. In the UK it is available from pharmacies and sexual health services, often under the brand ellaOne. It is taken as a single dose as soon as possible, and can still be used a little later in the cycle window than the older levonorgestrel emergency pill. It is not an abortion pill and does not work if pregnancy has already established.
How it works
Ulipristal works mainly by delaying or preventing the release of an egg from the ovary (ovulation). Around the time the body is about to release an egg, it can hold that release back so that any sperm already present do not meet an egg. Because it acts on ovulation, it is most useful when given before an egg is released, and the sooner it is taken the more likely it is to work.
Company & origin
Originated / developed by: HRA Pharma (originator).
An emergency contraceptive used in the UK after unprotected sex, taken as a single dose as soon as possible.
Practical use
How to take Ulipristal
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Take the single dose as soon as possible after unprotected sex — the sooner the better, though it can be used later in the window than levonorgestrel.
- Do not use it at the same time as the levonorgestrel emergency pill, and tell the pharmacist if you have used emergency contraception already this cycle.
- If you are restarting regular hormonal contraception, wait the advised time before doing so and use condoms in the meantime, as it can make the pill less effective.
- If you are breastfeeding, express and discard your milk for the advised short period after taking it.
- If you are sick within a few hours of taking it, contact a pharmacist as you may need a repeat dose.
Weighing it up
Advantages & disadvantages of Ulipristal
Advantages
- Can be used later after unprotected sex than the older levonorgestrel emergency pill.
- Taken as a single dose and available from pharmacies and sexual health services.
- Effective at delaying ovulation, especially when taken promptly.
Disadvantages
- Less effective if you are already on, or about to restart, hormonal contraception.
- Effectiveness is reduced by enzyme-inducing medicines and St John's wort.
- Breastfeeding must be paused for a short period, and it does not protect against later sex in the same cycle.
Practical use
Good to know
Take ulipristal as soon as you can after unprotected sex — it can be used later in the window than levonorgestrel, but effectiveness still falls the longer you wait. It is less effective if you have recently used, or are about to restart, hormonal contraception such as the pill, and it should not be taken together with the levonorgestrel emergency pill. Enzyme-inducing medicines and St John's wort can make it less reliable, in which case a copper coil (the most effective emergency method) may be advised. If you vomit within a few hours of taking it, you may need another dose. If you are breastfeeding, you are advised to pause and discard your milk for a short period afterwards. Always take a pregnancy test if your next period is late or unusually light.
Who should not take it / use with caution
- It is not used if pregnancy is already confirmed, as it will not end an established pregnancy.
- People with severe asthma controlled with steroid tablets are advised to avoid it.
- Anyone who has had an allergic reaction to ulipristal, or with significant liver problems, should seek advice first.
Monitoring
- No blood tests are needed; the main check is a pregnancy test if your period is late or unusual.
- Seek advice if you have severe lower tummy pain in the weeks after, as a precaution.
- A follow-up at a sexual health service can review ongoing contraception and any infection risk.
Side effects
- Headache, nausea, tummy pain and tiredness can occur.
- Your next period may come earlier or later than expected, or be heavier or lighter.
- Dizziness and breast tenderness are sometimes reported.
Key interactions
- Enzyme-inducing medicines and St John's wort can make it less effective; a copper coil may be advised instead.
- It should not be combined with the levonorgestrel emergency pill or used close to restarting hormonal contraception.
- Medicines that strongly reduce stomach acid may lower how well it is absorbed.
Available as: A single tablet taken by mouth.
Answers
Ulipristal: frequently asked questions
How is it different from the levonorgestrel morning-after pill?
Ulipristal can be effective taken a little later after unprotected sex, but the two should not be taken together, and the sooner either is taken the better.
Will my regular pill still work after taking it?
Ulipristal can make hormonal contraception less effective, so you wait the advised time before restarting it and use condoms in the meantime.
Is it the same as an abortion pill?
No. It works by delaying the release of an egg and does not end an established pregnancy; if you are already pregnant it will not work.
Can I take it while breastfeeding?
You can, but you are advised to express and discard your breast milk for a short period afterwards, as advised by the pharmacist.
What if my period is late afterwards?
Take a pregnancy test if your next period is more than a few days late, much lighter than usual, or you have any concerns.
The wider class
About Emergency contraception
Ulipristal belongs to the emergency contraception class. For how the class as a whole works, its shared safety principles and monitoring, see the full guide.
Browse by body system
Authoritative sources
- BNF
- NICE CKS
Building a medicines information resource?
We create evidence-led, dose-free drug and formulary references for teams.