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Synthetic Progestogen

Norethisterone

Brand names: Primolut N, Utovlan

Norethisterone is an orally active progestogen used for menstrual disorders such as heavy or painful periods, to delay menstruation, in endometriosis, and as a component of some hormonal contraceptives and hormone replacement therapy.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

Clinical monograph

How it works

It is a synthetic progestogen that acts on progesterone receptors to oppose oestrogenic effects on the endometrium and modulate the menstrual cycle.

Prescribing in practice

  • It is associated with an increased risk of venous thromboembolism, so assess thrombotic risk factors before prescribing, particularly at higher doses.
  • At higher therapeutic doses it can be partially metabolised to ethinylestradiol, which is relevant to thrombotic risk assessment.
  • It is not a reliable contraceptive at the doses used for menstrual disorders unless prescribed specifically as a contraceptive.

Monitoring

Review blood pressure, bleeding pattern and thrombotic risk factors, and reassess the need for continued treatment periodically.

Counselling the patient

  • Report symptoms of a blood clot such as leg pain or swelling, chest pain or breathlessness urgently.
  • When used for menstrual disorders this is not a contraceptive unless specifically prescribed as one.
  • Take regularly as directed for your indication and report any unusual bleeding.

Evidence & guidelines

Norethisterone is a long-established progestogen, and prescribing guidance highlights venous thromboembolism risk, especially at higher doses.

Reference: NICE NG88 (Heavy Menstrual Bleeding); FSRH Guideline; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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