Safety information · Internal patient-safety page
Levonorgestrel safety summary
Levonorgestrel is the emergency-contraception pill that works by delaying or blocking ovulation. It can be taken up to 72 hours (3 days) after unprotected sex, but the sooner the better. It is most effective within the first 12 hours. It does not interrupt an existing pregnancy.
What it's used for
- One 1.5 mg tablet, taken as soon as possible: effectiveness drops with every hour that passes.
- Can be taken at any point in the menstrual cycle, with or without food.
- If you vomit within 3 hours of taking it, the tablet has not been absorbed: take another one.
- It is a backup, not a regular contraceptive. It works less well than ongoing methods and does not protect for the rest of the cycle.
Most common side effects
- Nausea.
- Headache.
- Lower abdominal pain.
- Tiredness and dizziness.
- Breast tenderness.
- Light spotting or irregular bleeding until your next period: the period itself usually arrives on time, but can be a few days early or late.
Serious side effects: stop and seek care
- Sudden, severe lower abdominal pain, especially with a positive pregnancy test after use, can signal an ectopic pregnancy and needs urgent assessment.
- Severe allergic reaction: rash, swelling of the face or throat, difficulty breathing.
Who should not take it
- Allergy to levonorgestrel or any tablet ingredient.
- Severe liver disease.
- Tell the doctor about severe intestinal malabsorption (such as active Crohn's disease): the tablet may not absorb properly.
- Tell the doctor about a previous ectopic pregnancy or fallopian-tube infection.
Interactions to flag
- Rifampicin, some antiepileptics (carbamazepine, phenytoin, phenobarbital), some HIV medicines and St John's wort reduce effectiveness: tell your doctor, as a different method or approach may be advised.
- Ciclosporin: levonorgestrel can raise its levels.
- Your regular hormonal contraception can be restarted or continued straight away: use condoms as well until your next period.
Message us in the app chat if you notice any of these
- Your period is more than 5 days late, unusually light or unusually heavy: take a pregnancy test.
- Sudden severe lower abdominal pain: seek urgent care first.
- You vomited within 3 hours of the tablet.
- You want to sort out ongoing contraception so this stays a one-off.
AEMPS CIMA: Levonorgestrel 1.5 mg
Back to your consultationThis page summarises information from the regulator-approved leaflet for reference only. It is not medical advice and does not replace the assessment of an EU-licensed doctor. Your doctor will review your individual history, dose and interactions during your consultation.