Norethisterone

Norethisterone is a medication that is used to delay your period. It is a man-made version of the natural female sex hormone progesterone which has an essential role in controlling the menstrual cycle.

Norethisterone can be taken to delay your period because it stops your progesterone levels falling. Falling progesterone is what prompts the womb lining to be shed, resulting in a monthly bleed.

What is norethisterone used for?

Norethisterone is used to treat women with certain health conditions including:

• heavy or painful periods
• premenstrual tension (PMT)
• irregular periods
• endometriosis (a condition where womb tissue grows outside the womb)
• breast cancer

Norethisterone works to delay your period by increasing your progesterone levels before your period starts. Each month if you do not get pregnant your progesterone levels fall, causing your womb lining to shed, resulting in a period.

Norethisterone is a type of synthetic progesterone. So, when you take it, norethisterone keeps your progesterone levels raised so that you do not get your period, meaning you can delay it for up to 30 days.

Norethisterone comes in 5mg tablets and should be swallowed whole with water. It can be taken with or without food and it's safe to drink alcohol while taking norethisterone.

To delay your period, you normally take 5mg (1 tablet) 3 times a day (a total of 15mg), starting 3 days before your period is due to start and continuing for up to 30 days.

Your period will normally start within 3 days of stopping norethisterone.

When to start taking norethisterone

You’ll need to start taking norethisterone 3 days before your period is due for it to delay your period effectively.

What if I miss a pill?

If you forget to take a norethisterone pill, you should take the missed pill as soon as you remember, and then continue taking the rest of the pills at the usual time.

You should not take a double dose to make up for a forgotten dose. If it is near the time of your next scheduled dose, just skip the missed pill. Missing doses is more likely to cause breakthrough bleeding.

What happens if you take norethisterone too late?

If you start taking norethisterone less than 3 days before your period is due to start, then it is unlikely to delay your period and you may experience a bleed.

Can I take norethisterone during my period?

No, norethisterone should be started before your period begins for it to effectively delay your period. It will not delay or stop your period once it has started.

Like all medications, norethisterone can cause side effects, although not everyone will experience them.

Some side effects of norethisterone include:

• reduced sex drive
• changes to your menstrual cycle like irregular bleeding, spotting or breakthrough bleeding
• headaches
• nausea (feeling sick)
• bloating
• abdominal pain
• breast pain and tenderness
• hair loss
• feeling dizzy
• weight gain
• fluid retention
• hair growth on the face, chest, and back (hirsutism)

Norethisterone has been shown to slightly increase the risk of developing thromboembolism (blood clots) in the legs (deep vein thrombosis or DVT), brain (stroke), heart (heart attack), and lungs (pulmonary embolism or PE). This risk is increased if you:

• have had blood clots in the past, or have a family member who has had blood clots in the past
• are unable to move around for a long period of time because of illness, injury, or surgery
• are very overweight
• are a smoker
• have had repeated miscarriages in the past
• have systemic lupus erythematosus (SLE)

Other uncommon, but serious side effects of norethisterone include:

• severe allergic reaction (anaphylaxis)
• liver problems

You should stop taking norethisterone and seek immediate medical advice if you experience:

• wheezing (noisy, rapid breathing)
• difficulty breathing
• feeling faint or dizzy
• swelling of the face, tongue, hands, or feet
• severe itchy skin or rash
• sudden, severe chest pain
• coughing up blood
• fast heartbeat
• severe headache (migraine) or headache that doesn’t go away
• changes to your vision (sight)
• difficulty talking
• numbness or weakness in any part of your body
• swelling, pain, redness, and heat in your lower legs or ankles
• yellowing in your skin or the whites of your eyes (jaundice)

You can find a full list of potential side effects in the patient information leaflet that’s provided with norethisterone tablets. If you experience any side effects while taking norethisterone that are difficult to manage or if you’re concerned about symptoms you have been experiencing since taking the medication, speak to a doctor for advice.

Norethisterone is normally a safe medication, but it is not suitable for all women. Before prescribing norethisterone your doctor will ask you some questions to check that it is safe for you to take. You should not take norethisterone if you:

• are, or think you could be pregnant
• have had a severe allergic reaction to norethisterone, or any of the ingredients in norethisterone (norethisterone, lactose monohydrate, maize starch, polyvidone, and magnesium stearate)
• have ever had blood clots or have a close family member with a history of blood clots
• have a higher risk of blood clots
• have ever had a heart attack
• have ever had pemphigoid gestationis (a skin condition that occurs in pregnancy) or pruritus (itching all over your body) during pregnancy
• have porphyria ( an inherited blood disease)

Sometimes norethisterone isn’t safe for people with certain health conditions. You might not be able to use norethisterone if you have:

• diabetes
• epilepsy
• migraines
• heart problems
• kidney problems
• asthma
• liver problems
• unexplained vaginal bleeding (bleeding for which your doctor could not find a cause)

If you have one of these conditions, your doctor will decide if norethisterone is safe for you to take.

Depression has been reported in some women taking norethisterone. Talk to your doctor or healthcare provider if you feel low in mood while taking norethisterone.

Your doctor will ask you what other medicines you are taking before prescribing norethisterone. It’s important that you tell your doctor about any medications you are taking, including herbal supplements, as some may change the way norethisterone works in your body.

It’s important to read the patient information leaflet before taking norethisterone. Some medications that may interact with norethisterone include:

• epilepsy medications like Phenytoin and Carbamazepine
• antibiotics such as tetracyclines, rifampicin, and co-trimoxazole
• HIV medicines like ritonavir and nelfinavir
• some cancer medicines
• some herbal supplements like St John’s wort
• aminoglutethimide (a medication used to treat Cushing’s syndrome, seizures, breast, and prostate cancer)
• ciclosporin (a medication that suppresses the immune system)
• non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen and diclofenac
• some medications used to treat high blood pressure

Norethisterone is not suitable for everyone. However, there are alternatives available that may be more suitable for you to delay your period if you cannot take norethisterone.

Period delay tablets

Alternative period delay tablets available for prescription at ZAVA are Utovlan and Provera.

Utovlan is a branded version of norethisterone.It also norethisterone in a 5 mg dose and works in exactly the same way. Therefore, if norethisterone isn’t suitable for you, Utovlan is unlikely to be a suitable alternative.

Provera is a period delay tablet that contains a different type of synthetic progesterone called medroxyprogesterone acetate. It works in the same way as norethisterone in that it keeps progesterone levels raised to delay your period and is taken 2 to 3 days before your period is due to begin.

Provera is available ‘off label’ as 10mg tablets and is taken 3 times a day for as long as you want to delay your period for, up to a maximum of 30 days.

Contraceptive pills

If you are considering or currently taking the combined contraceptive pill, you can delay your period by taking the active pills daily without taking a break between strips. However, some women do experience some breakthrough bleeding, even when they take their pills back to back.

If you are not sure how to delay your bleeds with your combined pill, speak with your doctor or pharmacist and they should be able to advise.