Norethindrone: what it treats, how to take it, side effects
Last updated September 3, 2026.
Norethindrone is a progestin - it stops the lining of the uterus from growing and causes the uterus to produce certain hormones. At treatment doses it manages endometriosis and abnormal bleeding. (It is also sold in smaller amounts as a progestin-only contraceptive - a different product with its own instructions; this page covers the treatment uses.)
What does it treat?
Endometriosis - the pain and heavy, irregular bleeding that come when uterine-lining tissue grows outside the uterus - and abnormal periods or bleeding, including restarting a normal cycle in women who menstruated normally before but have not had a period for at least 3 months and are not pregnant or in menopause. It controls these conditions; it does not cure them.
How do you take it?
Schedules depend on the job: for endometriosis, once daily for 6 to 9 months, starting low with increases no more than every 2 weeks; to restart a cycle, once daily for 5 to 10 days during the second half of the planned cycle. Same time every day, exactly as directed. Do not stop without your doctor - even when you feel well. Missed dose: take it as soon as you remember, unless the next one is almost due - then skip it and never double up.
Side effects to know
- Common: irregular vaginal bleeding or spotting, changes in menstrual flow, enlarged or tender breasts, nausea, vomiting, bloating, weight changes, sleep trouble, acne, brown patches on the face, hair loss, and facial hair growth.
- Serious - uncommon, but call your doctor immediately: loss of vision, blurred vision, double vision, or bulging eyes; migraine headache; pain, warmth, or heaviness in the back of the lower leg; shortness of breath; coughing up blood; sudden sharp or crushing chest pain or heaviness in the chest; slow or difficult speech; and dizziness or faintness.
Who should not take it?
Report the full history before starting: the vision, leg-pain, chest-pain, and speech symptoms on the serious list are the clotting-pattern warnings, and any history of blood clots, stroke, or related conditions belongs in the prescriber conversation. Smoking raises those stakes. If you become pregnant, call your doctor.
When is it an emergency?
Sudden vision loss, crushing chest pain, coughing blood, one-sided weakness or garbled speech, or a hot swollen calf is a 911 call. For an overdose, call Poison Control at 1-800-222-1222. Pymander's escalation routing is built and tested specifically for this class of decision; see the safety architecture working paper.
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Common questions
Why am I spotting between periods on norethindrone?
The most common trade: irregular bleeding and spotting head the effects list because the progestin is actively reshaping the uterine lining it is suppressing. For endometriosis the course runs 6 to 9 months or until breakthrough bleeding becomes bothersome - that last phrase is straight from MedlinePlus, and it means spotting is expected, tracked, and worth mentioning at visits, but rarely a stop-sign on its own.
Why does norethindrone come with vision and leg-pain warnings?
Progestins sit in the hormone family that can shift clotting risk - so the serious list reads like a clot inventory: calf pain, warmth, or heaviness; chest pain or coughing blood; sudden vision changes; migraine; slow or difficult speech. Uncommon, but each is a stop-and-call event, and they are why the history questions (clots, stroke, smoking) come before the prescription.
Is norethindrone the same as the mini-pill?
Same molecule, different product and dose. Norethindrone is sold in smaller amounts as a progestin-only contraceptive - MedlinePlus keeps a separate monograph for that use, because the schedule and the missed-dose rules are entirely different. This page covers the treatment uses: endometriosis and abnormal bleeding. If your prescription is for contraception, follow that product's own instructions.
Why did my doctor start at a low dose for endometriosis?
Side effects scale with dose - nausea, breast tenderness, mood and sleep changes - so the label pattern is start low and increase no more than once every 2 weeks, landing on the lowest dose that controls the pain and bleeding. Slow, but it finds the dose you can actually live on for a 6-to-9-month course.
Why did my period stop - is that a problem?
Often the intended effect: norethindrone stops the uterine lining from growing, and for many on continuous dosing, periods lighten to spotting or pause entirely - that is the endometriosis tissue being quieted too. It is expected on this drug, not dangerous. What is not expected: a possible pregnancy (the drug is stopped if you conceive - call your doctor) or sudden heavy flooding, both of which get a call.
What happens if I miss a dose of norethindrone?
Take it as soon as you remember, unless it is almost time for the next one - then skip it and never double up. Same-time-daily is the anchor. Note that for the contraceptive version of this drug the missed-dose rules are far stricter - another reason the two products are not interchangeable.