✓ Medically reviewed by · Last reviewed: May 2026
Pharmacy Researcher · 8 years experience
Pharmacy researcher with 8 years reviewing clinical drug information, generic formulation equivalence, and international pharmaceutical standards. Focuses on patient-facing accuracy in medication education.
Quick Answer — What Is Primolut N?
Primolut N is a 5 mg norethisterone tablet by Bayer used to delay periods, control heavy or irregular bleeding, and manage endometriosis. To postpone a period, you take one tablet three times daily starting three days before the bleed is expected; menstruation returns 2–3 days after the last dose. Primolut N is a progestin only — it does not prevent pregnancy.
Travelling on the day your period is due? Heavy bleeding that has tipped from inconvenient to anaemia-risking? Endometriosis pain that flares with every cycle? Primolut N is one of the oldest and most reliable progestin tablets used to put the menstrual cycle on pause. This guide is the one your gynaecologist would write if she had a spare evening — what norethisterone actually does inside the uterus, how to dose it for each of its three main uses, which patients should avoid it, and how it compares to the four other progestins commonly prescribed for the same problems.
What Primolut N Is — and What It Isn’t
Primolut N is the Bayer brand for norethisterone (norethindrone) 5 mg, a first-generation synthetic progestin first synthesised in 1951 by Carl Djerassi’s team and the original molecule that made the contraceptive pill possible. It binds progesterone receptors in the uterus and, secondarily, weak androgen receptors elsewhere. That dual profile is why Primolut N works on the endometrium but also explains the mild androgenic side-effect profile (acne, hirsutism in long courses) that newer progestins like dydrogesterone do not produce.
It is not:
- An oral contraceptive — the dose is too high and the pulsed schedule wrong for reliable ovulation suppression. If you need contraception, see our birth control methods compared guide or the Yasmin combined-pill guide.
- An emergency contraceptive — that is levonorgestrel 1.5 mg as a single dose (Postpone 72 or i-Pill), used within 72 hours after unprotected sex.
- A natural progesterone — those are micronised progesterone capsules like Susten, used for luteal support in fertility and HRT.
The Three Things Primolut N Actually Treats
| Indication | How it works | Typical regimen |
|---|---|---|
| Period delay | Maintains progesterone receptor occupancy so the endometrium does not shed | 5Â mg three times daily, start 3 days before expected period, continue until you want the bleed (max ~14 days) |
| Heavy or prolonged bleeding (menorrhagia) | Stabilises the endometrium during acute bleed; in cyclical use, it organises the lining so withdrawal bleeds are lighter | Acute: 5 mg three times daily for 10 days. Cyclical: 5 mg twice daily on days 19–26 |
| Endometriosis | Continuous progestin suppression decidualises and atrophies ectopic endometrial tissue | 5 mg two to three times daily continuously for 4–6 months |
| Dysfunctional uterine bleeding | As above — used when no structural cause (fibroid, polyp) has been found | Per specialist, usually 5 mg twice or three times daily for 10 days then cyclical |
| Premenstrual syndrome (PMS) | Evidence is weak; sometimes used to stabilise luteal-phase mood symptoms | 5 mg twice daily, days 16–25 of cycle |
Two notes on this table. First, the 5 mg-three-times-daily total of 15 mg is a relatively high progestin load — much higher than the 0.35 mg in a desogestrel mini-pill like Cerazette. That high dose is what makes Primolut N effective for period delay, but it is also why side effects (bloating, breast tenderness, mood flatness) are noticeable and why it is not used for routine contraception. Second, the period-delay indication is the only one you can self-manage; the menorrhagia and endometriosis regimens belong inside a gynaecologist’s plan because the underlying diagnosis matters (a fibroid that is causing the bleed will not stop bleeding because you took norethisterone).
How to Use Primolut N for Period Delay — the Step-by-Step Protocol
Who this works for
Healthy women with regular cycles who want to push a single bleed back by up to ~14 days for a holiday, sporting event, wedding, or exam window. Not appropriate if you have a personal history of venous thromboembolism, active breast cancer, severe liver disease, or undiagnosed vaginal bleeding.
- Count back 3 days from your expected period start. If your cycle is reliable, this is straightforward — use a tracking app or the calendar. If your cycle is irregular, period delay with Primolut N is unreliable and you should speak to a clinician first.
- Take 1 × 5 mg tablet three times a day — morning, mid-afternoon, evening. Roughly eight hours apart works best. Take with water, with or without food (some women find the evening dose easier with food because of mild nausea).
- Continue the three-times-daily schedule until you want the bleed to start. The maximum useful course is around 14 days; beyond that you are loading progestin without benefit.
- Stop the tablets. Your period will start 2–3 days later. Withdrawal bleeding may be slightly heavier or lighter than usual for that first cycle.
- Resume normal cycle. Your next period after the withdrawal bleed should arrive on its usual rhythm. If it does not come within 6 weeks of the withdrawal bleed, do a pregnancy test.
The 3-days-before window matters because norethisterone needs time to reach steady-state progesterone-receptor occupancy in the endometrium before the natural progesterone drop that triggers menstruation. Start the day before and you will get breakthrough bleeding; start a week before and you are just dosing for longer with no extra benefit.
Norethisterone vs the Other Progestins — Which One for Which Job
This is where most guides stop. There are five progestins commonly prescribed in this space and they are not interchangeable. Here is the practical comparison.
| Progestin | Brand here | Best for | Weak point |
|---|---|---|---|
| Norethisterone 5 mg | Primolut N | Period delay; menorrhagia; endometriosis | Mild androgenic effects (acne, oily skin); modest VTE signal in older women |
| Dydrogesterone 10 mg | Duphaston | Threatened/recurrent miscarriage; luteal support in IVF; endometriosis | Not licensed for period delay in most countries; cost |
| Medroxyprogesterone 10 mg | Deviry, Meprate | Withdrawal bleed induction (Provera challenge); endometrial protection | Mood flatness; slower onset for period delay; metabolic effects |
| Micronised progesterone 200 mg | Susten | Fertility luteal support; HRT progesterone arm | Sedating; not used for period delay |
| Drospirenone (in combined pill) | Yasmin | Cycle control + contraception (skip the placebo week to skip a period) | Combined with estrogen — VTE/stroke risk needs assessing |
Three practical decisions fall out of this:
- One-off period delay, otherwise healthy: norethisterone (Primolut N) is the standard.
- Routine cycle control + you also want contraception: a combined pill like Yasmin taken back-to-back (skip the 7-day pill-free week) gives you both.
- Period delay but you cannot take estrogen (migraine with aura, smoker over 35, prior VTE): norethisterone is usually still acceptable, but discuss with a clinician — the VTE signal with high-dose progestins, while smaller than the combined-pill signal, is not zero.
How Norethisterone Actually Works (the Honest Mechanism)
In a natural cycle, the corpus luteum produces progesterone for 10–14 days after ovulation. Progesterone keeps the secretory endometrium intact. If pregnancy does not occur, the corpus luteum involutes, progesterone falls, the endometrium loses its hormonal support, and you menstruate.
Norethisterone is a 19-nortestosterone derivative — chemically a cousin of testosterone with progestin activity bolted on. At 5 mg three times daily, it produces serum levels that more than substitute for the natural progesterone drop. The endometrium reads “progesterone is still high” and does not shed. Stop the tablets and within 48–72 hours serum levels drop below the receptor-occupancy threshold and a withdrawal bleed begins.
The “19-nor” backbone is the reason Primolut N has a small androgenic footprint that dydrogesterone (a 21-carbon progesterone-derivative) does not. In short courses (≤14 days) this rarely matters; in 4–6 month endometriosis courses it can produce acne, oily skin, mild voice changes, or unwanted hair growth in a minority of women.
Side Effects — What’s Common and What Means Stop
Common (≥1 in 10), usually settle within days: headache, mild nausea, breast tenderness, bloating, mood flatness or irritability, mild fluid retention. These are dose-dependent — a 14-day course of three-times-daily dosing is more likely to produce them than a 5-day course.
Less common but worth knowing: spotting or breakthrough bleeding (especially if you start the tablets too close to your period), acne or oily skin (the androgenic signature), reduced libido, mild weight gain from fluid retention (the true fat-mass effect is small and reversible).
Stop and seek care
- Sudden calf pain, swelling, or warmth (possible DVT)
- Sudden breathlessness or pleuritic chest pain (possible PE)
- One-sided weakness, slurred speech, sudden severe headache, vision change (possible stroke)
- Yellowing of skin or eyes (possible liver injury)
- Severe abdominal pain
- Heavy vaginal bleeding that soaks a pad an hour for more than two hours
The thrombosis signal with norethisterone is smaller than with combined oral contraceptives but it is not zero, particularly in women over 35, smokers, those with obesity, and those with personal or first-degree-family VTE history. If you fit any of those profiles, get clearance before a course rather than just buying tablets.
Who Should Not Take Primolut N
- Pregnancy (norethisterone is not teratogenic at low contraceptive doses but is not used during a confirmed pregnancy; suspected pregnancy needs a test first)
- Active or past venous thromboembolism, arterial thrombosis, or known thrombophilia
- Severe liver impairment, active liver disease, or liver tumours
- Hormone-sensitive breast cancer (current or recent history)
- Undiagnosed vaginal bleeding (the bleeding itself needs investigation first)
- Severe diabetes with vascular complications
- Migraine with aura — discuss with a clinician; this is a hard contraindication for the combined pill but a relative caution for high-dose progestin only
Common Misconceptions
“Primolut N is a contraceptive.” It is not. The dose is too high and the schedule wrong. If you are using Primolut N to delay a period and are sexually active, use a condom or another method. Pregnancy that occurs while taking norethisterone is not a high-risk pregnancy — the molecule is not teratogenic — but it is an unintended one.
“I can just keep taking it until my next period.” The endometrium tolerates ~14 days of high-dose progestin well; beyond that you are loading drug with no benefit and increasing the risk of breakthrough bleeding, mood effects, and (over months) the small VTE signal. If you need to suppress periods for longer than a fortnight on a one-off basis, you need a different plan — usually back-to-back combined pills or a continuous progestin like Cerazette.
“5 mg of norethisterone is the same as the norethisterone in my mini-pill.” No. Progestin-only pills like Cerazette use desogestrel 0.075 mg, or in older formulations norethisterone 0.35 mg. Primolut N at 5 mg is roughly 14× the contraceptive dose — a different drug from a clinical-effect perspective.
“Period delay tablets cause infertility.” They do not. A short course does not affect future fertility; even repeated courses (one or two per year) have not been linked to fertility problems in cohort studies. Endometriosis-dose continuous courses (4–6 months) suppress ovulation while you are on them, and fertility returns within 1–3 cycles after stopping.
Comparing Primolut N to “Skipping the Placebo Week”
If you take a monophasic combined contraceptive pill — Yasmin, Microgynon, Loette — you can usually skip a period simply by starting the next pack the day after your active pills end (no placebo week). This is sometimes called “tricycling” or “extended-cycle pill use”. For women already on a combined pill, it is the simpler approach: no extra drug, no separate prescription, and contraception is maintained.
For women not on a pill, or on a progestin-only pill, Primolut N is the standard. The mini-pill Cerazette does not allow reliable period skipping in the same way because its bleeding pattern is already unpredictable. The same applies to the Diane-35 anti-androgen pill used for acne and PCOS — it is taken cyclically and the bleed is part of how it is monitored.
How to Order Primolut N Online from MedsBase
📦 Every order is covered by our Reshipment Assurance Policy — if your parcel does not arrive within 20 business days we will reship it.
Place your order on the Primolut N product page. Typical delivery is two to three weeks depending on destination; orders are dispatched from a WHO-GMP-certified manufacturer in plain packaging. Card payments are routed through a regulated processor and your bank statement will show the processor name (a regulated card-payment processor) — never “MedsBase” or any medication name. If you prefer to avoid card processing entirely, choose crypto or SEPA bank transfer at checkout.
For a wider view of the women’s health catalogue — combined pills, progesterone, emergency contraception, HRT — see the women’s health category page.
Frequently Asked Questions
How long does Primolut N take to work?
For period delay, take the first tablet three days before your expected period; it begins working within hours of the first dose by saturating progesterone receptors. For menorrhagia (acute heavy bleeding), bleeding usually slows within 24–48 hours of starting 5 mg three times daily.
How long after stopping Primolut N will my period come?
Two to three days after the last tablet. If it does not arrive within six weeks of stopping, take a pregnancy test — period delay tablets do not prevent pregnancy and a missed conception during the course is the usual explanation.
Can Primolut N cause weight gain?
Fluid retention is common in the first week and can show as 1–2 kg on the scale. True fat-mass weight gain from a short course is small and reversible once the tablets are stopped. The 4–6 month endometriosis courses can produce 2–4 kg of real weight gain in a minority of users.
Is Primolut N safe to take during a holiday?
For most healthy women, yes — that is exactly what the period-delay indication is for. The caveat is long-haul flights plus high-dose progestin: the small additive VTE signal becomes worth taking seriously. Move every two hours on the flight, stay hydrated, and consider compression stockings if the flight is over six hours.
Can I drink alcohol while taking Primolut N?
Yes. Norethisterone is not metabolised by the same liver pathways as alcohol and there is no clinically relevant interaction. Heavy alcohol intake plus any high-dose hormone is not great for the liver, but social drinking on a holiday is fine.
Does Primolut N protect against pregnancy?
No. The dose schedule is wrong for reliable ovulation suppression. Use a condom or another contraceptive method if you are sexually active during the course.
What if I miss a dose?
Take it as soon as you remember unless you are within three hours of the next dose, in which case skip the missed dose and take the next one on schedule. Do not double up. A single missed dose may produce breakthrough bleeding that does not, on its own, mean the course has failed — but two or more missed doses in 24 hours often means the bleed will start before you finish the course.
Can I use Primolut N for PCOS-related irregular periods?
It is sometimes prescribed as a withdrawal-bleed inducer in PCOS — usually as a 5–10 day course at 5 mg twice daily — to bring on a planned bleed and reset endometrial protection. It does not treat the underlying insulin-resistance or androgen-excess problems of PCOS; for that, metformin, combined oral contraceptives like Diane-35, and lifestyle interventions do the actual work.
How is Primolut N different from Provera (medroxyprogesterone)?
Both are synthetic progestins. Norethisterone is a 19-nortestosterone derivative — faster-acting for period delay, mildly androgenic. Medroxyprogesterone (Deviry, Meprate) is a 17α-hydroxyprogesterone derivative — slower-acting, more sedating, used more often for withdrawal-bleed induction and endometrial protection in HRT than for period delay.
Can men take Primolut N?
Norethisterone has been used in some niche endocrinology settings, but Primolut N is licensed for women only and there is no reason for a man to take it. The androgenic signature does not produce useful muscle effects and the dose schedule is wrong for any male indication.
Is Primolut N the same as Norethindrone?
Yes — norethisterone (the European INN) and norethindrone (the US name) are the same molecule. Primolut N is the Bayer brand of the 5 mg tablet; generic 5 mg norethisterone tablets are clinically equivalent.
The Short Version
Primolut N is norethisterone 5 mg — a high-dose progestin tablet that does three things well: it postpones a single period when started three days before the bleed; it reins in acute or chronic heavy menstrual bleeding; and at continuous dosing for four to six months it shrinks endometriosis. It is not a contraceptive and should not be confused with the low-dose norethisterone in a mini-pill. The drug has a long safety record, but the thrombosis signal in women over 35, smokers, and those with VTE history is not zero. For a one-off holiday delay in an otherwise-healthy woman, it is the standard and reliable choice.
Medical disclaimer
This guide is educational and does not replace a consultation with a clinician. Period delay tablets are well-tolerated by most healthy women but are not appropriate for every patient. If you have a history of venous thromboembolism, breast cancer, severe liver disease, undiagnosed vaginal bleeding, or are pregnant, do not start Primolut N without medical advice. If you develop sudden chest pain, breathlessness, calf swelling, neurological symptoms, or jaundice while taking it, stop the medication and seek urgent care.
Written by
Sophie ChenPharmaceutical Content Researcher · 8 years experience
Sophie Chen is a pharmaceutical content researcher with 8 years covering generic medication access and clinical pharmacology. She specialises in international regulatory frameworks, bioequivalence standards, and patient-facing education on therapeutic drug classes. She is not a clinician.