What is Norethisterone?
Norethisterone is a medication used for period delay in women. It contains a synthetic form of the female hormone progestogen. Norethisterone can be used to manage heavy, painful or irregular periods, as well as to treat endometriosis.
Norethisterone is a prescription only medication. You must have a prescription before you buy norethisterone. Alternatively, we can prescribe it to you at Instant eCare. Contact us to find out more.
For more information about norethisterone, consult the patient information leaflet.
How it works
Norethisterone belongs to a group of medications called progestogens, a synthetic version of the natural hormone progesterone. In a usual menstrual cycle, you experience a period when your levels of oestrogen and progesterone drop. However, if you take norethisterone, it provides a sustained level of the hormone in the body, extending your cycle and delaying your period.
Norethisterone is not a contraceptive, and even though it will delay your period, it will not prevent you from becoming pregnant. You still need to use a suitable contraceptive method while taking norethisterone if you do not want to become pregnant.
Before you take it
You must not take norethisterone if you have had an allergic reaction to norethisterone or any of the other ingredients in this medication. A full list of ingredients is contained within the patient information leaflet. Speak with your doctor, who may be able to recommend an alternative medication.
If you are pregnant, or think you may be pregnant, you should not take norethisterone. Your doctor may give you a pregnancy test before starting treatment, or if you miss a period during treatment.
Do not take norethisterone if you have ever had vaginal bleeding for which your doctor could not find a cause, if you or an immediate family member has ever had a problem with blood clotting, if you have ever had a heart attack or if you have a condition known as porphyria (a rare inherited blood disease.)
Norethisterone may be unsuitable for you if you have epilepsy, migraine headaches, asthma, heart problems or kidney problems. Talk to your doctor or pharmacist before taking norethisterone, as they will be able to advise you as to whether it is appropriate for you to take.
Norethisterone may increase your risk of experiencing venous thromboembolism. All women have a small chance of experiencing this, but the risk is marginally increased when taking norethisterone. You are more likely to experience a clot while taking norethisterone if you are very overweight, have previously experienced a blood clot, are unable to move for a long period of time (such as after an operation) or have a history of repeated miscarriage.
Norethisterone may interact with some other medications. Tell your doctor before you take norethisterone if you are taking any of the following:
- Antiviral medications to treat HIV, such as ritonavir or efavirenz
- Medicines to treat epilepsy, such as phenytoin or carbamazepine
- Medicines for high blood pressure
- Herbal preparations such as St John’s Wort
- Non-steroidal anti-inflammatory drugs for pain relief
- Immune system suppressants such as ciclosporin
This is not an exhaustive list of warnings and interactions. For a complete list, consult the patient information leaflet.
You should always take norethisterone exactly as your doctor or pharmacist has prescribed. Never exceed the stated dose. If you are in any way unsure of how to take norethisterone, you should consult your doctor or pharmacist for advice.
To delay your period, you should take one 5mg tablet three times per day. You must start taking the tablets three days before your period is due to start. Your period will start within three days of finishing norethisterone.
If you do not have a period when you finish a course of norethisterone, check with your doctor as you may be pregnant.
Store norethisterone in a cool, dry place, free from heat and moisture. Keep it out of reach of children and pets.
Common Side Effects of Norethisterone
Norethisterone may cause unwanted side effects, although these are usually mild to moderate in nature. If, however, these side effects concern you, consult your doctor. Side effects may include:
- Change in your period - breakthrough bleeding, spotting or stopping of periods
- Nausea or vomiting
Norethisterone may cause more serious side effects. If you experience these, you should go to your doctor. Side effects can include:
- Breast discomfort or tenderness
- Increased blood pressure
- Hair loss
- Skin reactions such as acne, itching or rash
Norethisterone may also cause a serious allergic reaction. This is rare, but an allergic reaction is an emergency, so if you believe you are experiencing one, you should immediately seek medical advice. Symptoms can include:
- Hives or nettle rash
- Swelling of the tongue, mouth, lips or throat
- Skin rash - itching, peeling, swelling
- Trouble breathing or speaking
This is not a complete list of side effects. For more information, consult the patient information leaflet.Frequently Asked Questions
Is norethisterone suitable for children?
Norethisterone should not be taken by anyone under the age of 18 to delay periods. We do not prescribe any medications to anyone under the age of 18.
I’m pregnant. Can I take norethisterone?
Do not take norethisterone if you are pregnant. This is because the hormones contained in this medicine can harm a developing baby. You must use a form of contraception while taking norethisterone, as it is not a contraceptive.
What happens if I miss a dose?
Take your tablets as soon as you remember, and continue taking your tablets at the scheduled time. Do not take two doses to make up for a missed dose.
What happens if I take too much?
If you think you have taken too much norethisterone, consult your doctor immediately.