Norethindrone

Aygestin · Micronor · Camila

Progestogen Oral FDA/EMA Label

Half-life

8 hr

Time to Peak

1.5 hr

Steady State

~2 days

Bioavailability

65%

Dose Range

0.35–5 mg

Frequency

Daily

Overview

Synthetic progestogen (also called norethisterone). One of the oldest and most widely used progestogens. Available in low-dose (0.35 mg, progestogen-only pill) and high-dose (5 mg, Aygestin) formulations. Used for contraception, menstrual regulation, endometriosis, and occasionally in HRT regimens.

Mechanism of Action

Synthetic progestogen with progestational, estrogenic (via aromatization), and androgenic activity. Acts primarily on progesterone receptors to suppress ovulation and modify the endometrium.

Dosing Information

Route	Dose Range	Half-life	Tmax	Frequency
Oral	0.35–5 mg	8 hr	1.5 hr	Daily

Used in Regimens

Norethindrone is not currently part of any catalog regimen.

Data Sources

FDA Label Aygestin (norethindrone acetate) FDA Prescribing Information
FDA Label Micronor (norethindrone) FDA Prescribing Information

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