Indications
Norethindrone (also called Norethisterone) is a man-made form of progesterone, a female hormone. It is used to treat abnormal or heavy menstrual bleeding, missed periods (secondary amenorrhoea), endometriosis (when tissue like the womb lining grows outside the womb) and to delay a period for a short time. Some low-dose forms are used as a progestogen-only birth control pill.
How It Works
It acts like natural progesterone. It changes the lining of the womb so that it becomes stable and stops shedding irregularly. At contraceptive doses it thickens the mucus at the neck of the womb so sperm cannot pass easily, and it may stop ovulation (release of an egg).
Dosage and Administration
The dose and length of treatment depend on the reason it is used, so take it exactly as prescribed by your doctor. Tablets are swallowed with water, at about the same time each day. For contraception, a pill must be taken every day without a break; a late pill can reduce protection. Do not stop or change the dose on your own.
Interactions
Medicines that speed up liver enzymes can make it less effective, for example Rifampicin, Carbamazepine, Phenytoin, Phenobarbital, some HIV medicines and St John’s Wort. It may affect blood sugar control in people taking diabetes medicines. Tell your doctor about all medicines and herbal products you use.
Contraindications
- Known or suspected pregnancy
- Unexplained vaginal bleeding that has not been checked by a doctor
- Current or past breast cancer or other hormone-sensitive cancer
- Severe or active liver disease or liver tumours
- Current or past blood clots, stroke or heart attack (for higher-dose treatment)
- Allergy to Norethindrone
Side Effects
Common effects include irregular bleeding or spotting, breast tenderness, headache, nausea, bloating, weight change, mood changes and acne.
Get urgent medical help if you have pain or swelling in one leg, sudden chest pain or breathlessness, sudden severe headache, problems with sight or speech, yellow skin or eyes, or severe lower tummy pain.
Pregnancy and Lactation
Do not use during pregnancy. If you think you may be pregnant, stop and see your doctor. Low-dose progestogen-only pills are generally considered suitable while breastfeeding; for higher doses, ask your doctor first.
Precautions and Warnings
Tell your doctor if you have diabetes, high blood pressure, migraine, depression, epilepsy, kidney or heart disease, or a history of clots. Higher-dose treatment may raise the risk of blood clots, especially with long travel or surgery. It does not protect against sexually transmitted infections.
Overdose
Overdose may cause nausea, vomiting and vaginal bleeding. Serious harm is unlikely, but contact a doctor or hospital for advice.
Therapeutic Class
Progestogen (synthetic female sex hormone).
Storage
Store below 30°C in a dry place, away from light and out of the reach of children.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.