Norethisterone

Norethisterone is a type of progestogen (a synthetic version of the female sex hormone progesterone). It 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 can also be used to delay menstruation to a later date. For example, if you have a special event or holiday coming up and it would be inconvenient to have your period during that time. Norethisterone is not a birth control method and does not stop you from getting pregnant.

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

When a woman gets pregnant, progesterone is produced by the body in order to maintain the pregnancy. One of the ways it does this is by preventing the shedding of the lining of the womb (your period). Norethisterone is a synthetic form of progesterone that keeps your progesterone levels high, stops your body from shedding the womb lining and delays your period.

Common 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 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)

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

Having blood tests while taking norethisterone

Some blood test results, such as tests for your hormone levels, can be affected if you are taking norethisterone and the results may not be accurate. Tell your doctor if you need to have any blood tests while you are taking norethisterone.

Pregnancy and norethisterone

It is not safe to take norethisterone when you are pregnant as it may affect the development of your baby. Sometimes your doctor will ask you to take a pregnancy test before starting norethisterone to make sure you are not pregnant. Norethisterone is not a contraceptive (birth control) pill, and you can become pregnant while taking it. You should use another form of birth control, like condoms, while you are taking norethisterone to protect against pregnancy.

Breastfeeding and norethisterone

Norethisterone is generally thought to be safe to take when you are breastfeeding. If you are breastfeeding, talk to your doctor before taking norethisterone and they will decide if it is safe for you.

Some alternative treatments, including apple cider vinegar, lentils, gelatine and vigorous exercise, may claim to delay your period. None of these have been proven to work and some may cause adverse side effects. In addition to norethisterone, the following hormonal methods can also delay your period:

Utovlan and Primolut are brand names for norethisterone and contain the same active ingredient as norethisterone.

The combined contraceptive pill contains both oestrogen and progestogen. It is normally taken for 21 days followed by a break of 7 days during which you have your period. If you start another course immediately without the 7 day break, you will “skip” your period that month.

Provera is another type of hormone medicine that can be used to delay your period. It contains medroxyprogesterone. It is used off label to delay your period, which means that the manufacturer has not listed this as a use, however it is usually recommended if norethisterone is not safe for you to use, as it does not have the same high risk of blood clots.