Norethisterone is a period delay medication that can allow you to delay your period for up to 17 days.
How to take Norethisterone tablets
You should take the first table three days before your period starts. Then take one tablet three times a day for no more than 20 days. You can take Norethisterone for less time if you don’t want to delay your period for the full 17 days.
Once you stop taking Norethisterone your period should start within two to three days. Your menstrual cycles should continue as usual after this first period. If you do not get your period, you should do a pregnancy test and contact your GP.
Who is Norethisterone not suitable for?
There are certain conditions which mean Norethisterone pills won’t be suitable for you, these include if you have a history of blood clots, are pregnant or breastfeeding.
How does Norethisterone work?
Norethisterone is a synthetic form of the hormone progesterone. Rather than allowing for the natural fall in progesterone during your period, Norethisterone keeps your progesterone levels up. This delays the shedding of your womb lining and therefore delays your period.
How long after taking Norethisterone will my period start?
Your period should start within three days of stopping your Norethisterone treatment. If your period hasn’t restarted after three days, get in touch with your GP as soon as you can.
Does Norethisterone reset your cycle?
Some of the reported side effects of Norethisterone can include changes to your cycle like a missed period or a period where you don’t ovulate.
What happens if I take Norethisterone too late?
If you take Norethisterone closer than three days before your period, your period may not be delayed. This is because the treatment hasn’t had the chance to offset the lowered progesterone levels that would induce a period.
Norethisterone side effects
Side effects of Norethisterone can include:
- Nausea (feeling sick)
- Breast tenderness
- Tiredness
- Bloating
- Reduced sex drive
- Headaches
- Bleeding and spotting between periods
- Changes to your cycle (i.e. not ovulating)
- Dizziness
- Changes to mood (euphoria, confusion, nervousness)
- Constipation
- Dry mouth
- Disturbed liver function
- Liver disorder
- Effects on your metabolism (alteration of blood sugar, insulin)
- Effects on the heart and circulation
- Acne
- Hair growth and loss
- Hives
- Fluid retention, swelling of hands and ankles
- Weight gain
Please stop Norethisterone and talk to your GP immediately if you begin to experience the following:
- Allergic reaction
- Signs of a blood clot (thrombosis): sudden, severe, sharp pains, coughing up blood, severe or long headaches, severe pain and swelling in the calf, ankle or foot
- Yellowing skin / whites of the eyes (jaundice)
- Migraine headache for the first time
Rarely, it can cause symptoms of some chronic diseases to get worse. Our clinicians will advise you on this once you’ve completed your online assessment. We’ll also need a recent blood pressure reading to make sure this treatment is safe for you.
For full information on side effects and correct use, see the patient information leaflet. If any side effects concern you, contact us via your Patient Record.
Effectiveness of Norethisterone
Norethisterone should be taken three days before you expect your next period to begin. It should become effective immediately at delaying your period for up to 17 days (if all 20 day’s worth of pills are taken).
To be effective you need to take three pills a day. Once you stop taking them, your period should start within 3 days.
Norethisterone is not a form of contraception. It cannot be used to prevent pregnancy. When taking Norethisterone you should use alternative contraception such as condoms.
