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GENITO URINARY SYSTEM AND SEX HORMONES › SEX HORMONES AND MODULATORS OF THE GENITAL SYSTEM › PROGESTOGENS AND ESTROGENS IN COMBINATION › Progestogens and estrogens, sequential preparations
norethisterone and estrogen
G03FB05
Forms & Strengths
- Tablets: norethisterone 0.5-1mg, estrogen 0.035-0.05mg
- Patches: norethisterone 0.25-0.5mg, estrogen 0.025-0.05mg/24hr
- Injections: norethisterone 200-350mg, estrogen 1-5mg
- Implants: norethisterone 68mg, estrogen 20mg
Adult Dosing
- Menstrual regulation: 0.5-1mg norethisterone, 0.035-0.05mg estrogen daily
- Contraception: 0.5-1mg norethisterone, 0.035-0.05mg estrogen daily
- Hormone replacement therapy (HRT): 0.5-1mg norethisterone, 0.035-0.05mg estrogen daily
Pediatric Dosing
- Not recommended for use in children prior to menarche
- After menarche, follow adult dosing guidelines
Indications
- Contraception
- Menstrual regulation
- Hormone replacement therapy (HRT) for menopausal symptoms
- Dysmenorrhea
- Endometriosis
Mechanism of Action
- Norethisterone: progesterone receptor agonist
- Estrogen: estrogen receptor agonist
- Combined effect: inhibition of ovulation, thickening of cervical mucus, and alteration of endometrium
Contraindications
- Pregnancy
- Breastfeeding
- Undiagnosed vaginal bleeding
- Thromboembolic disorders
- Liver disease
- Hypersensitivity to norethisterone or estrogen
Adverse Reactions
- Nausea and vomiting
- Headache
- Dizziness
- Breast tenderness
- Weight gain
- Mood changes
- Vaginal discharge
- Breakthrough bleeding
Drug Interactions
- Barbiturates: decrease norethisterone and estrogen efficacy
- Rifampin: decrease norethisterone and estrogen efficacy
- Anticonvulsants: decrease norethisterone and estrogen efficacy
- Grapefruit juice: increase norethisterone and estrogen levels
Curated Content: Needs Vetting Before Put to Clinical Use