Norethisterone acetate (NETA), also known as norethindrone acetate and sold under the brand name Primolut-Nor among others, is a progestin medication which is used in birth control pills, menopausal hormone therapy, and for the treatment of gynecological disorders. The medication available in low-dose and high-dose formulations and is used alone or in combination with an estrogen. It is ingested orally.
Side effects of NETA include menstrual irregularities, headaches, nausea, breast tenderness, mood changes, acne, increased hair growth, and others. NETA is a progestin, or a synthetic progestogen, and hence is an agonist of the progesterone receptor, the biological target of progestogens like progesterone. It has weak androgenic and estrogenic activity and no other important hormonal activity. The medication is a prodrug of norethisterone in the body.
NETA was patented in 1957 and was introduced for medical use in 1964. It is sometimes referred to as a "first-generation" progestin. NETA is marketed widely throughout the world. It is available as a generic medication.