Chemical Name: 19-nor-17α-ethynyltestosterone
Molecular Formula: C20H26O2
Molecular Weight: 298.4
CAS: 68-22-4

Norethisterone Description and Indication

Norethisterone is a molecule used in some combined oral contraceptive pills and in some progestogen only pills. At low doses, it prevents the release of an egg from the ovaries and increases the thickness of the natural mucus in the womb. At high doses, it may inhibit the pituitary gland. Norethisterone is a synthetic, potent, orally active progestogen. Due to the last mentioned, it produces secretory effects on estrogen-primed genital tissue, has a sedative effect on uterine muscle and a styptic effect on uterine hemorrhage.

Norethisterone tablets are used to treat a number of disorders of the menstrual cycle, including bleeding from the uterus, pre-menstrual symptoms (headaches, migraine, breast discomfort, racing pulse or changes in behavior prior to menstruation), painful periods, endometriosis and heavy bleeding. It is also prescribed in certain cases of breast cancer and to delay the onset of the period.

Norethisterone Mechanism of Action

Norethisterone has typical effects of a progestogen and converts the endometrium from the proliferative to the secretory phase. It may also have some estrogenic, anabolic and androgenic activities. The ingredient’s contraceptive effects are due to negative feedback inhibition of pituitary gonadotropin, whereby it prevents ovulation.

Norethisterone Dosage

Norethisterone can be administered for a wide variety of progestogen related issues and can be administered in various formulations, orally, or through intra-muscular or trans-dermal administration.

Norethisterone Contraindications

Norethisterone is contraindicated in patients with the following conditions:

Norethisterone Adverse Drug Effects

Norethisterone Drug Interactions

Norethisterone may antagonize the effects of antidiabetics, while its own effects may be reduced by Griseofulvin, possibly by accelerated metabolism of the progestogen. The effects of Norethisterone will be altered if other sex hormones are prescribed simultaneously.

Norethisterone Formulations

Norethisterone Brands

These are the following brands available for Norethisterone:

  • Brevicon
  • Brevicon 0.5+35
  • Brevicon 1+35
  • Brevicon 20
  • Brevinor
  • Dianor
  • Estrostep 21
  • Micronor
  • Micropil
  • Noriny1
  • Ortho 777-28
  • Ortho Novin 1/50
  • Ortho Novum 1/35
  • Ortho Novum 1/50
  • Ortho Novum 10/11
  • Ortho Novum 7/7/7
  • Ovacon
  • Ovcon 35