NOR-QD
Clinical safety rating: caution
Comprehensive clinical and safety monograph for NOR-QD (NOR-QD).
Progestin-only contraceptive; suppresses ovulation and alters cervical mucus and endometrium to inhibit sperm penetration and implantation.
| Metabolism | Hepatic via CYP3A4; metabolites are inactive. |
| Excretion | Renal (approximately 30-50% as metabolites, <10% unchanged) and fecal (40-60% via biliary excretion); enterohepatic recirculation contributes to sustained levels. |
| Half-life | Terminal elimination half-life (norethindrone) is 7-8 hours; clinical effect duration supports once-daily dosing. |
| Protein binding | 95-97% bound, primarily to albumin (61%) and sex hormone-binding globulin (SHBG, 36%). |
| Volume of Distribution | 3.5 ± 1.2 L/kg; consistent with extensive tissue distribution and accumulation in adipose tissue. |
| Bioavailability | Oral: 55-65% (first-pass metabolism; absolute bioavailability may vary with formulation). |
| Onset of Action | Oral: contraceptive effect requires consistent dosing for 48-72 hours; follicular suppression begins after 3-5 days. |
| Duration of Action | 24 hours; maintains contraceptive efficacy for one day with missed dose guidelines requiring backup contraception if >3 hours late. |
0.35 mg orally once daily, taken at the same time each day.
| Dosage form | TABLET |
| Renal impairment | No dose adjustment required for renal impairment. |
| Liver impairment | Contraindicated in severe hepatic disease (Child-Pugh Class C); use with caution in mild to moderate impairment (Child-Pugh A or B). |
| Pediatric use | Not indicated for use in pediatric patients. |
| Geriatric use | Not indicated for use in postmenopausal women; efficacy and safety not established in elderly. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for NOR-QD (NOR-QD).
| Breastfeeding | Excreted in breast milk. M/P ratio not established. May reduce milk production and quality. Not recommended during breastfeeding; alternative contraception should be used. |
| Teratogenic Risk | FDA Pregnancy Category X. Contraindicated in pregnancy due to known teratogenicity. First trimester: Increased risk of neural tube defects, cardiovascular anomalies, and limb reduction defects. Second and third trimesters: Risk of fetal feminization in males (pseudohermaphroditism) and possible genital anomalies. Use only if pregnancy has been definitively excluded. |
■ FDA Black Box Warning
Cigarette smoking increases risk of serious cardiovascular events; use with caution in women over 35 who smoke.
| Serious Effects |
["Known or suspected pregnancy","Hypersensitivity to norethindrone","Hepatic impairment","Undiagnosed abnormal genital bleeding","Known or suspected breast cancer"]
| Precautions | ["Thrombotic disorders","Ectopic pregnancy","Hepatic disease","Irregular bleeding","Bone mineral density changes"] |
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| Fetal Monitoring |
| Monitor: Pregnancy status before initiation and monthly. Liver function tests, blood pressure, and signs of thromboembolism. If pregnancy occurs, discontinue immediately and monitor fetal development via ultrasound. |
| Fertility Effects | May delay return to fertility after discontinuation due to ovulation suppression. No permanent effects on fertility after cessation. |