Norethisterone

What is Norethisterone?

Norethisterone is a hormone that can be taken to delay your period. This is for times when having your period would be inconvenient, for example during a wedding, holiday or sporting competition. It is also sometimes prescribed to ease period problems and help endometriosis.

How does Norethisterone work?

Norethisterone essentially works by making your body think that you are pregnant to prevent the womb lining from breaking down and exiting as period blood. Norethisterone is a synthetic version of the sex hormone progesterone. When progesterone levels are high, this causes the lining of the womb to thicken, in preparation for a fertilised egg to implant. Progesterone levels usually drop when fertilisation doesn't occur, causing your period to happen. When you take norethisterone, the progesterone levels remain high, leaving the womb lining intact until you stop taking it.

How long can you take Norethisterone?

How long you take norethisterone for depends on why you are taking it. For period delay, you can take it for up to 20 days. If you have been prescribed norethisterone for another reason e.g. treating painful, heavy periods or endometriosis then follow your doctor's instructions. You’ll often take it for 3–6 months in these cases.

Active ingredients

5mg of norethisterone is the active ingredient. 

Inactive ingredients

The inactive ingredients are lactose, maize starch and magnesium stearate.

Please note: Different brands of generic norethisterone may contain different inactive ingredients than those listed here.

How to take Norethisterone

To delay your period, you should start taking norethisterone 3 days before your period is due. The tablets should be taken 3 times a day for a maximum of 20 days (including the 3 days before your period). Once you stop taking them, your period should return 3 days after. Always follow the instructions given by your doctor, because how you take norethisterone depends on why you are taking it.

Norethisterone side effects

Common side effects include: 

• Spotting or breakthrough bleeding 
• Headaches
• Nausea

You may also experience:

• Altered vaginal discharge
• Cervical erosion (a harmless condition that may cause you to have an abnormal smear result)
• Mood changes including depression
• Dizziness
• Fatigue
• Insomnia (difficulty falling asleep)
• Prolonged anovulation (not producing an egg from an ovary for several months)
• Nervousness
• Confusion
• Euphoria (elevated mood)
• Loss of concentration
• Vision disorders
• Vomiting
• Jaundice (yellowing of the skin)
• Constipation or diarrhoea
• Dry mouth
• Disturbance in liver function
• Altered fat levels in the blood
• Altered glucose metabolism and exacerbation of diabetes
• Tremors
• Sweating
• Leg cramps
• Blood clots such as deep vein thrombosis and pulmonary embolism
• Heart attack (myocardial infarction)
• Stroke
• Heart failure
• Increased blood pressure 
• Palpitations
• Fluid retention 
• Breast tenderness
• Acne
• Migraines
• Rash, which may be itchy
• Weight gain
• Hair loss
• Low sex drive 
• Increased hair growth

If you experience any of the following side effects you should stop taking Norethisterone right away and see your doctor as soon as possible: 

• Severe headaches or migraines
• Pain or swelling in the leg
• Pain when breathing or coughing 
• Coughing up blood
• Difficulty breathing or wheezing 
• Numbness up one side of the body
• Affected hearing or vision
• Yellowing in your skin or eyes

Contraindications

Norethisterone is not suitable for women who:

• Are pregnant
• Are allergic or sensitive to any of the ingredients
• Have unexplained vaginal bleeding 
• Have a history of breast or genital cancer
• Have venous thromboembolic disease e.g. deep vein thrombosis or pulmonary embolism
• Have arterial thromboembolic disease e.g. angina or heart attack
• Have ever experienced a heart attack, stroke or angina
• Have liver problems 
• Have ever experienced jaundice
• Have porphyria
• Have a history or pemphigoid gestationis
• Have a history of pruritus (itching) in pregnancy

Extra care should be taken if you:

• Have epilepsy
• Have problems with your kidneys 
• Have heart failure
• Experience migraines
• Have high blood pressure
• Are diabetic 
• Have gallstones 
• Have systemic lupus erythematosus
• Have a history of depression 

If you have any of the aforementioned conditions, speak with your healthcare provider.

Drug interactions

The following medicines can interfere with the way Norethisterone works: 

• Rifampicin 
• Rifabutin 
• HIV Medicines 
• Griseofulvin
• Epilepsy medication
• Ulipristal
• St John's wort 

Can I take Norethisterone with the contraceptive pill?

If you are taking the combined contraceptive pill then there is no need to take norethisterone. You can delay your period by skipping the seven-day break and running two packs together. You can take norethisterone along with the progestogen-only pill (mini pill) however. Your doctor will need to assess whether or not the combination is suitable for you, as there are certain risk factors involved in taking norethisterone such as blood clots and interactions with other medicines.

Alcohol and Norethisterone

Drinking alcohol while you are on norethisterone will not produce any adverse effects.

Norethisterone vs Utovlan

Norethisterone is the generic name for the medication, Utovlan is a specific brand of norethisterone. Both work in the same way and produce the same possible side effects.

Norethisterone vs contraceptive pill for period delay

Both the contraceptive pill and norethisterone contain synthetic versions of the progesterone hormone. Which method is best will depend on your own circumstances and your current method of contraception. If you are already on the combined pill then it's very easy to delay your period. Simply skip the pill-free week and start a new pack the day after you reach the end of your current pack. If you wish to delay your period for a one-off occasion and don't have time to plan ahead, then norethisterone may be the best option. 

Both methods have the side effect of breakthrough bleeding, so neither method will 100% guarantee you will have no bleeding on a particular day.

Is Norethisterone a contraceptive pill?

Norethisterone is not a contraceptive pill and cannot be used to prevent pregnancy. It should always be used in conjunction with your preferred method of contraception. If you are on the combined pill then this can be used on its own to delay your period. Ask your doctor for advice if you are taking the progestogen-only pill and want to delay your period using norethisterone.

Is Norethisterone safe?

Norethisterone is generally safe to use occasionally. However, it should not be used continuously and it is not suitable for everyone. Women who have a history of blood clots may be at risk and your doctor will check your medical history to ensure that Norethisterone is safe for you to use. 

Can Norethisterone stop a period once it has started?

There is no way to stop your period once it has started. Norethisterone will only work if you take it before your period is due to prevent it from happening. 

Will Norethisterone affect your fertility?

Norethisterone may affect your fertility while you are taking it. If you are trying to get pregnant then norethisterone may not be suitable for you to use. Norethisterone does not affect your long-term fertility.