Norethisterone is a prescription medication belonging to the class of drugs called progestogens, which are synthetic versions of the female hormone progesterone. Its primary function is to replicate progesterone’s effects, helping to regulate the menstrual cycle and manage hormonal conditions. Available in tablet form, Norethisterone is used for several distinct medical purposes determined by a healthcare provider. This guide offers general information but is not a substitute for professional medical advice or consultation with your doctor.
Defining Its Purpose
The medication is prescribed to manage conditions related to hormonal imbalance and the menstrual cycle by stabilizing the uterine lining. A common use is controlling abnormal or heavy menstrual bleeding (menorrhagia). For this, it is often administered in a short course to stop acute bleeding, followed by a cyclical regimen to prevent recurrence.
Norethisterone is also used for the long-term management of endometriosis, where it suppresses the growth of ectopic tissue by providing a continuous supply of progestogen. This helps alleviate associated pain and symptoms. It may also be prescribed to treat severe premenstrual tension (PMT) by modulating hormonal shifts.
Its most known application is the temporary postponement of a period for social or travel reasons. The medication maintains a high level of progestogen, preventing the natural drop in hormones that triggers menstruation. When taken for period delay, Norethisterone is not a reliable form of contraception, and a separate method must be used if pregnancy prevention is desired.
Step-by-Step Usage Guidelines
Proper administration requires consistency, as timing and dosage vary significantly based on the condition treated. For optimal absorption, swallow the tablets whole with water, ideally at the same time each day. Following the exact instructions given by the prescribing physician is paramount.
Period Delay Regimen
For temporary period delay, the typical regimen is 5 milligrams three times a day (15 mg total daily dose). Treatment must begin three days before the expected start date of the period to stabilize the uterine lining. You can continue taking the tablets for up to 14 to 20 days. A withdrawal bleed will typically commence within two to four days after the medication is stopped.
Bleeding and Endometriosis Regimens
For heavy or irregular bleeding, a short, high-dose course is often prescribed, such as 5 milligrams three times daily for ten days, to quickly stop the bleeding. To prevent recurrence, a lower dose (e.g., 5 milligrams twice daily) may be continued cyclically.
If prescribed for endometriosis, the regimen is usually continuous and long-term, often involving 5 milligrams three times daily for at least six months. If breakthrough bleeding occurs during endometriosis treatment, the dosage may be temporarily increased to ensure tissue suppression.
The duration of treatment is strictly defined by the physician. Never stop the medication early or extend the course without explicit medical instruction.
Addressing Missed Doses and Vomiting
Adherence to the daily schedule is important. If a dose is missed, take it as soon as you remember. However, if it is close to the time for your next scheduled dose, skip the forgotten tablet and take the next dose at the usual time.
Never attempt to compensate for a missed dose by taking two tablets at once, as this increases the risk of side effects. If you miss multiple doses or are unsure of the protocol, contact your healthcare provider.
If pregnancy prevention is relevant, missing a dose may compromise effectiveness, requiring the use of a barrier method, such as condoms, for the following days.
If severe vomiting or diarrhea occurs within two to three hours of taking a tablet, the medication may not have been fully absorbed. Treat this situation as a missed dose and follow the same protocol. If stomach upset is persistent, use an alternative form of protection for the next 48 hours.
Safety and Warnings
Norethisterone is not suitable for everyone. Inform your doctor of your complete medical history before starting treatment. The medication should not be used if you have:
- Known hypersensitivity to the ingredients.
- A history of certain cancers.
- Severe liver disease.
- A previous or current blood clot (e.g., deep vein thrombosis or pulmonary embolism).
- A history of stroke or heart attack.
Common side effects include mild nausea, headaches, breast tenderness, or temporary mood changes. Irregular vaginal bleeding or spotting between periods is also frequent, especially during the initial months. These effects often subside as your body adjusts, but if they persist or become bothersome, discuss them with your doctor.
Seek immediate medical attention if you notice signs of a serious side effect, such as:
- Symptoms of a blood clot (sudden chest pain, shortness of breath, or swelling and pain in a leg).
- Sudden vision changes.
- Severe new onset of migraine headaches.
- Signs of liver problems (yellowing of the skin or eyes).
Norethisterone can interact with other medications, including certain antibiotics, anti-epileptic drugs, and herbal supplements like St. John’s wort. These interactions can reduce its effectiveness or increase the risk of adverse effects.