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GENITO URINARY SYSTEM AND SEX HORMONES › SEX HORMONES AND MODULATORS OF THE GENITAL SYSTEM › HORMONAL CONTRACEPTIVES FOR SYSTEMIC USE › Progestogens
norethisterone
G03AC01
Forms & Strengths
- Tablets: 0.35mg, 5mg, 10mg, 15mg, 20mg, 25mg, 30mg, 35mg
- Injections: 200mg/mL, 50mg/mL
- Implants
Adult Dosing
- Contraception: 0.35mg daily
- Dysfunctional uterine bleeding: 5-15mg daily for 5-10 days
- Endometriosis: 10-20mg daily for 8-10 weeks
- Menopausal symptoms: 1-5mg daily
Pediatric Dosing
- Not recommended for children under 16 years
- For girls with primary amenorrhea: 2.5-5mg for 5-7 days, repeat after 2 weeks if necessary
Indications
- Contraception
- Dysfunctional uterine bleeding
- Endometriosis
- Menopausal symptoms
- Amenorrhea
- Female infertility
Mechanism of Action
- Progestogen receptor agonist
- Suppresses gonadotropin release from the pituitary gland
- Inhibits ovulation
- Thickens cervical mucus to prevent sperm entry
Contraindications
- Known or suspected pregnancy
- Undiagnosed vaginal bleeding
- Active liver disease or liver cancer
- Thrombophlebitis or thromboembolic disorders
- Severe hypertension
Adverse Reactions
- Weight gain
- Dizziness
- Headache
- Nausea and vomiting
- Breast tenderness
- Mood changes
- Skin rash or itching
Drug Interactions
- Inducers of hepatic enzymes (e.g., phenobarbital, phenytoin, carbamazepine) may decrease norethisterone efficacy
- Inhibitors of hepatic enzymes (e.g., ketoconazole, erythromycin) may increase norethisterone levels
- Interaction with warfarin, requiring dose adjustment
Curated Content: Needs Vetting Before Put to Clinical Use