Norethisterone: Uses, How It Works, Medicines
Norethisterone is a prescription hormone tablet that acts like the natural hormone progesterone. It is used for period problems such as heavy, painful or irregular periods, endometriosis, premenstrual syndrome and, in some people, to postpone a period. It is not a contraceptive when used this way.
Also known as: Norethindrone, Norethisterone tablet, Norethisterone 5 mg, Primolut N
Pharmacist review in progress. This page is based on the sources listed below and is being checked by our registered pharmacist.
How does Norethisterone work?
Norethisterone is a progestogen that steadies the womb lining. While it is taken the lining does not shed, and bleeding follows when the course stops.
How to take Norethisterone
Follow the label or your doctor's advice. The number of tablets and the days they are taken depend on the reason it is prescribed. Tablets are swallowed whole with some liquid.
Side effects of Norethisterone
Many people take norethisterone without serious problems. Some effects are common, but a few need medical advice.
Uncommon or mild
- Spotting or bleeding between periods, or lighter periods
- Headache
- Nausea
- Swelling of hands or feet (fluid retention)
- Absent periods when taken for endometriosis
Rare but serious: get medical help
- Swelling of the face, lips or throat, or trouble breathing (a severe allergic reaction). Get medical help immediately
- Pain or swelling in one leg, sudden chest pain or breathlessness (possible blood clot)
- New or worse severe headache, or sudden vision or hearing changes
- Yellow skin or eyes (possible liver problems)
- A big rise in blood pressure, or worsening low mood
Who should be careful
Norethisterone is partly changed into oestrogen in the body, so some of the cautions for combined contraceptive pills also apply. Tell the doctor your full history.
When the label says not to use it
- Pregnancy, or possible pregnancy
- Breastfeeding
- Current or past blood clots in a vein or artery
- Migraine with warning symptoms such as vision or speech changes
- Severe liver disease or a liver tumour
- Breast cancer or another hormone-dependent cancer, known or suspected
- Vaginal bleeding that has not been explained
- Allergy to norethisterone or any ingredient
- It does not protect against pregnancy when used for period problems or to delay a period; use another method if needed
- Smoking, being overweight, a family history of clots and long periods of immobility add to clot risk; the UK label advises stopping about six weeks before planned surgery
- Diabetes: blood sugar may need more checks
- Epilepsy, migraine, asthma, heart or kidney problems: fluid retention can make these worse
- A history of depression: tell the doctor
- Dark patches on the face (chloasma) can appear; limit strong sun and UV exposure
- If a period does not arrive after a course, pregnancy must be ruled out
Medicines and things that interact with Norethisterone
Some medicines can change how norethisterone works. Tell your doctor about everything you take, including herbal remedies.
- Medicines for epilepsy such as phenytoin, carbamazepine and primidone, and barbiturates: may make it work less well
- Rifampicin, and HIV medicines such as ritonavir, nevirapine and efavirenz
- St John's wort
- Azole antifungals, macrolide antibiotics, verapamil, diltiazem and grapefruit juice: may raise its level
- Ciclosporin and lamotrigine levels may be changed
If someone takes too much
No harm has been reported from overdose and treatment is usually symptomatic. If someone takes much more than prescribed, ask a doctor or go to the nearest hospital with the pack.
Regulatory status in India
Approved for sale in India as a prescription medicine. Single-ingredient norethisterone is not on the CDSCO list of medicines banned under section 26A of the Drugs and Cosmetics Act. Check the pack for the schedule.
Type of medicine
Norethisterone belongs to this type of medicine.
Medicines that contain Norethisterone
These medicines sold in India contain Norethisterone. They are listed A to Z, not ranked.
- Primolut N · 5 mg tablet
What is Norethisterone used for?
Medicines that contain Norethisterone are used for these conditions.
Other medicines of the same type
These active ingredients are of the same type as Norethisterone.
Common questions
Does norethisterone prevent pregnancy?
Not when it is taken for period problems or to delay a period. You can still become pregnant, so another method of contraception is needed. Norethisterone is contraindicated in pregnancy. Ask your doctor if you may be pregnant.
Can it be used to delay a period?
It is used for this in some people, started before the expected period and taken only as the doctor directs. In the UK the NHS generally does not prescribe it just to delay a period. Ask a doctor, because it is not suitable for everyone.
When does bleeding start after stopping?
A period usually starts within a few days of the last tablet when it is used to postpone a period. If it does not, or bleeding is unusually heavy, see a doctor.
Sources
- Primolut N (norethisterone): usage. RxReasoner (summary of the UK Summary of Product Characteristics)
- Primolut N (norethisterone): precautions. RxReasoner (summary of the UK Summary of Product Characteristics)
- Choosing a medicine to delay periods. Specialist Pharmacy Service (NHS)