Norethisterone has typical effects of a progestogen and converts the endometrium from the proliferative to the secretory phase. It may also have some oestrogenic, anabolic and androgenic activities, but these may not be significant. Norethisterone delays onset of periods and controls abnormal uterine bleeding. It also has contraceptive effects due to negative feedback inhibition of pituitary gonadotropin thus preventing ovulation.
(in Tablet form)
Breast cancer: 40 mg daily increasing to 60 mg daily if no regression is noted.
Contraception: 0.35 mg daily, or 0.5-1 mg daily when combined with oestrogen. As acetate: 0.6 mg daily, or 1-1.5 mg daily when combined with oestrogen.
Premenstrual syndrome: 5 mg tid on days 16-25 of cycle.
Progestogen component of menopausal hormonal replacement therapy: 0.7 mg as a continuous daily dose. As acetate: 1 mg daily for 10-12 days of a 28-day cycle.
Endometriosis: 10-25 mg daily continuously for 4-9 mth. As acetate: 5-15 mg daily, start at 5 mg daily and increase by 2.5 mg at 14 day intervals. Take continuously for 4-9 mth.
Menorrhagia: 10-15 mg daily in a cyclical regimen. Usual dose: 5 mg tid for 10 days as primary treatment, subsequently 5 mg bid on days 19-26 of cycle to prevent recurrence. As acetate: 2.5-10 mg daily in a cyclical regimen, beginning during the assumed latter half of the cycle.
Postponement of menstruation: 5 mg tid starting 3 days before expected onset of menstruation.
Manufacturer: Opsonin Pharma Ltd.