NORINYL 1+80 28-DAY
Clinical safety rating
cautionComprehensive clinical and safety monograph for NORINYL 1+80 28-DAY (NORINYL 1+80 28-DAY).
Combination oral contraceptive containing a progestin (norethindrone) and an estrogen (mestranol). Suppresses gonadotropin (FSH and LH) release via negative feedback, inhibiting ovulation. Also induces changes in cervical mucus and endometrium to impede sperm penetration and implantation.
| Metabolism | Norethindrone undergoes hepatic metabolism via reduction and conjugation; major enzyme CYP3A4. Mestranol is rapidly demethylated to ethinyl estradiol, which undergoes hepatic metabolism via CYP3A4 and conjugation. |
| Excretion | Norethindrone is primarily excreted in urine (approximately 60%) and feces (approximately 40%) as glucuronide and sulfate conjugates. Mestranol is metabolized to ethinyl estradiol; ethinyl estradiol and its metabolites are excreted in urine (40%) and feces (60%). |
| Half-life | Norethindrone: terminal elimination half-life of 5.3-10.5 hours; Mestranol (as ethinyl estradiol): terminal half-life of 7-20 hours. Clinically, steady state is achieved after 5-7 days of daily dosing; the half-life supports once-daily dosing for consistent hormonal levels. |
| Protein binding | Norethindrone: 80-85% bound to albumin and SHBG; Mestranol (as ethinyl estradiol): 95-98% bound to albumin. |
| Volume of Distribution | Norethindrone: Vd ~ 4.0 L/kg, indicating extensive tissue distribution; Mestranol (as ethinyl estradiol): Vd ~ 1.5-2.5 L/kg. |
| Bioavailability | Norethindrone: oral bioavailability ~ 64%; Mestranol: rapidly metabolized to ethinyl estradiol, with combined effects providing oral contraceptive efficacy. Both components are administered orally. |
| Onset of Action | Oral administration: contraceptive effect requires 7 days of continuous use to inhibit ovulation; for cycle control, effects begin within the first cycle. |
| Duration of Action | Contraceptive effect persists for at least 24 hours with daily dosing; after discontinuation, return of ovulation may occur within 1-2 weeks but can be delayed. |
| Molecular Weight | 599.85 |
One tablet (1 mg norethindrone / 80 mcg ethinyl estradiol) orally once daily for 28-day cycle without placebo.
| Dosage form | TABLET |
| Renal impairment | No dose adjustment required; use with caution in severe renal impairment (GFR <30 mL/min) due to potential fluid retention. |
| Liver impairment | Contraindicated in acute liver disease or decompensated cirrhosis (Child-Pugh class B or C). Use with caution in mild hepatic impairment (Child-Pugh class A) with monitoring. |
| Pediatric use | Not indicated for prepubertal females. Postmenarchal adolescents: same adult dosing; adjust if <45 kg with caution. |
| Geriatric use | Not indicated for postmenopausal women due to increased risk of thromboembolism and lack of contraceptive benefit. |
| 1st trimester | Contraindicated; use during early pregnancy increases risk of congenital anomalies, particularly cardiac defects and limb reduction defects. Risk is dose-dependent. |
| 2nd trimester | Contraindicated; use during mid-pregnancy may cause fetal harm, including genital abnormalities in female fetuses and potential metabolic effects. |
| 3rd trimester | Contraindicated; use in third trimester is associated with fetal adrenal suppression, metabolic disturbances, and potential withdrawal symptoms in neonates. |
Clinical note
Comprehensive clinical and safety monograph for NORINYL 1+80 28-DAY (NORINYL 1+80 28-DAY).
| Placental transfer | Both components cross the placenta. Norethindrone and ethinyl estradiol achieve significant fetal serum levels, with fetal-to-maternal ratios approximately 0.5-0.7 for norethindrone and 0.2-0.5 for ethinyl estradiol. |
| Breastfeeding | Norethindrone and ethinyl estradiol are excreted in breast milk in small amounts. Estrogen-containing contraceptives may reduce milk production and quality, especially in early postpartum period. Use only if benefits outweigh risks; consider progestin-only alternatives. |
| Lactation Rating | L3 (Moderately Safe) / Avoid if possible |
| Teratogenic Risk | FDA Pregnancy Category X. Contraindicated in pregnancy due to estrogen component (mestranol) and progestin (norethindrone). First trimester: increased risk of congenital anomalies, including cardiovascular defects and limb reduction defects. Second and third trimesters: potential for androgenic effects on female fetus (pseudohermaphroditism), and possible long-term effects from estrogenic activity. Not recommended for use during pregnancy. |
| Fetal Monitoring | Monitor for pregnancy symptoms prior to initiating therapy. In case of accidental exposure during pregnancy, monitor fetal development via ultrasound. Assess for signs of pregnancy if therapy is ongoing. No specific monitoring required for fetal effects if used as directed (contraindicated in pregnancy). For lactation, observe infant for any adverse effects. |
| Fertility Effects | Oral contraceptives suppress ovulation and are used to prevent pregnancy. May cause temporary delay in return to fertility after discontinuation. In some cases, used to treat menstrual irregularities and endometriosis, which may improve fertility outcomes after cessation. No permanent impact on fertility. |
■ FDA Black Box Warning
Cigarette smoking increases risk of serious cardiovascular events from combination oral contraceptives. Risk increases with age (especially >35 years) and with heavy smoking (≥15 cigarettes/day). Women who use combination oral contraceptives should be strongly advised not to smoke.
| Serious Effects |
Known or suspected pregnancyThrombophlebitis or thromboembolic disordersCurrent or history of breast cancerEstrogen-dependent neoplasiaUndiagnosed abnormal genital bleedingHepatic adenoma or carcinomaActive liver disease or impaired liver functionKnown hypersensitivity to any component
| Precautions | Increased risk of thrombotic and thromboembolic events (e.g., MI, stroke, VTE), especially in smokers >35 years and those with hypertension, diabetes, hyperlipidemia, or obesity. Discontinue if thrombotic event occurs. Hepatic neoplasia risk. Elevated blood pressure. Gallbladder disease. Carbohydrate/lipid effects. Worsening of depression. Fluid retention. Hereditary angioedema. Chloasma. Lens opacities. Discontinue if jaundice develops. Use caution with history of depression, diabetes, or familial hyperlipidemia. |
| Food/Dietary | No specific food restrictions. Grapefruit juice may slightly increase estrogen levels; moderate consumption is acceptable. Consistent dietary habits are recommended to maintain stable hormone levels. |
| Clinical Pearls | Combined hormonal contraceptive containing 1 mg norethindrone and 0.035 mg ethinyl estradiol. 28-day regimen with 21 active pills and 7 placebo pills. For patients with compliance concerns, consider a 24-day active regimen alternative. Not recommended for patients with migraine with aura or smokers over 35. Monitor blood pressure at baseline and annually. Counsel on increased VTE risk, especially in first year of use. Use with caution in patients with uncontrolled hypertension, diabetes with vascular disease, or history of DVT/PE. |
| Patient Advice | Take one pill daily at the same time for full contraceptive efficacy. · If you miss a pill, refer to the package insert instructions; use backup contraception if needed. · Common side effects include nausea, breast tenderness, and breakthrough bleeding, usually improving within 3 months. · Do not smoke while taking this medication; smoking increases risk of serious cardiovascular events. · Report sudden severe headache, chest pain, shortness of breath, or leg swelling to your healthcare provider. · This does not protect against HIV or other sexually transmitted infections; use condoms for STI prevention. · Inform your healthcare provider about all medications and supplements, as some may reduce effectiveness. |
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