Norethisterone 5mg (also known as Primolut N)

Norethisterone is a synthetic form of the naturally occurring hormone in your body called progesterone. Therefore, it mimics the action of progesterone and can delay your period when taken 3 days before your period is due to start. The body sheds your womb lining, which is what your period consists of; when the progesterone levels in your normal monthly cycle begin to fall. By increasing the progesterone levels we can delay this process.

Even though norethisterone mimics progesterone, a hormone also in contraceptive pills, it cannot be used as birth control. It also cannot be used in conjunction with the combined contraceptive pill but can be used with the mini (progesterone only) pill. Norethisterone should not be taken by pregnant or breastfeeding women.

One tablet should be taken three times a day, with eight hours between each pill; and should start to be taken three days before you expect to start your period. Norethisterone can be taken continuously for up to 20 days, a total of 60 tablets, and you should start your period a few days after stopping taking the tablets. This form of period delay should not be used more than once every six months.

You must stop taking Norethisterone immediately and seek advice from your GP if you experience jaundice, migraines, swelling in the face or extremities or a tight chest.

Other less serious side effects may include:

• Rash
• Nausea
• Headaches
• Fatigue
• Breast swelling or tenderness
• Bloating or a change in weight

Risk of Venous Thromboembolism (VTE)

Any alteration to the natural hormone rhythm in your body may slightly increase  your chance of having a blood clot in the veins of the lungs or legs. More information can be found in the patient information leaflet.

Patient Information Leaflet for Norethisterone 5mg