Blog A Guide to Norethisterone

Norethisterone acetate is a synthetic hormone, and has many uses. 

Often found in combined oral contraceptive pills (COC’s), along with doses of progesterone and estrogen, and widely used for menstrual delay treatment and to help manage heavy, painful and/or irregular periods.

Norethisterone can also be used in treating premenstrual tension (PMT), and Endometriosis (where tissue from the womb is found in other places such as the ovaries and fallopian tubes)

How does Norethisterone work?

Simply put, Norethesterone works by mimicking the effects of the body’s natural progesterone. 

Norethisterone is a synthetic progestogen hormone which can stop uterine bleeding and also has oestrogenic activity. 

Its presence in the body causes antiestrogenic activity by  thickening the cervical mucus, thus making it difficult for the sperm to reach the place of fertilisation. 

Norethisterone also works by stopping the lining of the uterus from growing and by causing the uterus to produce certain hormones.

What Does Norethisterone Do? 

Norethesterone is a progestomimetic, and is used to supply the body with female hormones. This makes it perfect for treating women with progesterone deficiency. It is also involved in the thickening of the endometrium, and retaining the uterine lining and thus postpones the date of menstruation (period delay) in premenopausal women.

Norethisterone is therefore used to treat endometriosis and functional hemorrhages, and painful periods caused by dysmenorrhea (heavy bleeding). 

Taking norethisterone over a specific number of days can act as a contraceptive if taken along with progesterone and oestrogen in a combined oral contraceptive preparation. 

Does Norethisterone Reset Your Cycle? 

Your menstrual cycle will start between two  to four  days once you stop using Norethisterone. Some women have reported changes in their cycle once they started using Norethisterone, but this usually changes later. You should consult your doctor if you are worried about changes to your menstrual cycle.

Can Norethisterone Stop A Period Once Started?

No. You can only use Norethisterone to delay your periods before they start. It should be taken three  days before your period is due for safe and effective results. Use the right dose of one 5mg tablet taken three times a day for 14 days. You will start experiencing your period again two to three days once you stop using the tablet. 

Is Norethisterone A Contraceptive? 

Norethisterone on its own can only be used as a contraceptive when the hormone is administered as an injection. The injection provides contraception for about eight weeks. It stops ovulation and changes the uterus lining, making it difficult for the egg to attach to it even if it were to fertilise. It also makes the mucus forming in the cervix thicker, which prevents the sperm from getting to the womb for fertilisation. 

However, when Norethisterone is used as a COC, it does not prevent fertilisation in any way. It does not block the egg from getting fertilised when the sperm reaches the egg. If you want to avoid pregnancy, your doctor may prescribe specific contraceptive pills, which can contain norethisterone alongside other progesterone and oestrogens.

How Long Does Norethisterone Take To Work?

This usually varies between different women. You should start taking it three days before your period to ensure your progesterone levels don’t fall and to increase its chances of working in delaying your period. 

Medical experts recommend up to 30 days of use, taken three3 times a day. If you plan to delay your period for more than a month,  consult your doctor about using a combined contraceptive pill instead. (This should only be taken once a day). 

The Effectiveness of Norethisterone

The effectiveness of Norethesterone allows it to be widely used in gynecology. It is often combined with the other female hormone (estrogen) for contraceptive purposes, but it can also be used independently. The progestogen properties of Norethesterone makes it possible to postpone menstruation for up to 10-days by taking the tablet three times a day, starting three days before the normal onset.

Norethisterone is effective against endometriosis at a dose of one tablet per day for several months. A period of 10 days may be sufficient for the functional bleeding and the menorrhagia that accompanies the fibroids. A half-tablet should be taken again between the 16th and the 25th day. 

For contraception purposes (used only as part of a combined oral contraceptive), take one tablet daily from the 5th to the 25th day of each menstrual cycle.

Is Norethisterone Safe? 

Norethisterone is safe to be used occasionally by most women, but it should not be used regularly to delay periods. Like other medications, how perfectly it works will vary from one woman to another. Some of the side effects a few women have experienced from using it include acne, low mood, fluid retention, breast tenderness, and loss of libido.

Norethisterone is safe for most women. It should be avoided by pregnant women or those who think they might be expectant. You should consult your doctor or any other general practitioner if you are unsure about the medication. They will advise you further.

Can I Buy Norethisterone Over The Counter In The UK? 

Drugs containing Norethisterone have become available to buy over the counter, however, you will require a valid prescription. It is still advisable to consult your own GP or doctor before using them to ensure you get the right medication and stay free from some side effects. Your doctor may examine your body and recommend what is best for you. 

You can also get it through online consultation with a licensed prescriber for short term use. This medication is contraindicated in cases of undiagnosed genital bleeding, breastfeeding, pregnancy, as well as the risk of thromboembolic events.

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