Also called Primolut N®

Norethisterone is used for endometriosis, heavy menstrual periods, irregular periods and premenstrual syndrome (PMS), Find out how to take it safely and possible side effects. Norethisterone is also called Primolut N.

Type of medicine Also called
  • Progestogen hormone
  • Belongs to a group of medicines known as progestogens
  • Primolut N®

What is norethisterone?

Norethisterone belongs to a group of medicines called progestogens. Progestogen is very similar to the hormone progesterone that your body makes naturally. Norethisterone has different uses such as for endometriosisheavy menstrual periodsirregular periods and premenstrual syndrome (PMS), many symptoms women may have before their menstrual period each month. 

In New Zealand, norethisterone is available as tablets (5 mg) called Primolut N®. 

Norethisterone is also available in a lower dose as a contraceptive pill for women, to prevent pregnancy, called Noriday®. It's a progestogen-only oral contraceptive pill or mini pill. Read more about the mini pill.


  • The dose of norethisterone will be different for different women.
  • The usual dose is 5 mg two or three times a day. 
  • Take norethisterone exactly as your doctor tells you to. You may be asked to take the tablets every day, or to take them just on certain days of your monthly cycle. The pharmacy label on your medicine will tell you how much norethisterone to take, how often to take it and any special instructions.

How to take norethisterone

  • Swallow your tablets with a glass of water.
  • You can take norethisterone with or without food.
  • If you forget to take your dose, take it as soon as you remember that day. But, if it is nearly time for your next dose, just take the next dose at the right time. Do not take double the dose.

Precautions before taking norethisterone

It’s important that you tell your doctor or pharmacist before you start using norethisterone if you:

  • are pregnant or think you may be pregnant
  • are breastfeeding
  • have blood clots such as in the blood vessels in your legs (deep vein thrombosis), lungs (pulmonary embolism), heart (heart attack), brain (stroke) or any other parts of your body.
  • Have ever had depression.
  • are planning to have any surgery (operation). 

Sometimes a medicine isn’t suitable for a person with certain conditions, or it can only be used with extra care. 

What are the side effects of norethisterone?

Like all medicines, norethisterone can cause side effects, although not everyone gets them. 

Side effects What should I do?
  • Feeling sick (nausea)
  • Headache
  • Mood changes
  • These are quite common when you first start taking norethisterone and usually go away with time.
  • Tell your doctor if troublesome. 
  • Changes in weight
  • Difficulty sleeping
  • Bloating 
  • Swollen feet and ankles (fluid retention)
  • Breast tenderness
  • Changes in sexual desire
  • Tell your doctor if troublesome.
  • Signs of a possible blood clot such as pain or tightness in your chest, cough, difficulty breathing, severe headache, problems with your eyesight, pain in your legs, dizziness or fainting 
  • Tell your doctor immediately or ring HealthLine 0800 611 116. 
Did you know that you can report a side effect to a medicine to CARM (Centre for Adverse Reactions Monitoring)? Report a side effect to a product


Norethisterone may interact with a number of important medications and herbal supplements so check with your doctor or pharmacist before you start taking norethisterone or any other medicines.

Learn more

The following is further reading that gives you more information on norethisterone.

Medsafe Consumer Information Sheet: Primolut N


  1. The pharmacological management of endometriosis BPAC 2013
  2. Norethisterone (endocrine) New Zealand Formulary
Credits: Sandra Ponen, Pharmacist. Reviewed By: Angela Lambie, Pharmacist, Auckland Last reviewed: 14 Jul 2017