Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
NORINYL vs ALTAVERA
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Combination of norethindrone (progestin) and ethinyl estradiol (estrogen) provides contraception by inhibiting gonadotropin secretion via negative feedback on the hypothalamic-pituitary-ovarian axis, suppressing ovulation, increasing cervical mucus viscosity, and altering endometrial receptivity.
Combination of ethinyl estradiol and desogestrel: ethinyl estradiol suppresses gonadotropin release, inhibiting ovulation; desogestrel (progestin) causes cervical mucus thickening and endometrial atrophy, preventing implantation.
Prevention of pregnancy,Acne vulgaris (off-label),Dysmenorrhea (off-label),Endometriosis (off-label)
Prevention of pregnancy,Treatment of moderate acne vulgaris (in females ≥15 years with no contraindications)
One tablet (norethindrone 1 mg/ethinyl estradiol 0.035 mg) orally once daily for 21 days, followed by 7 placebo tablets. For first cycle, start on first Sunday after menstruation begins or on day 1 of menstrual cycle.
1 tablet (ethinyl estradiol 0.03 mg / levonorgestrel 0.15 mg) orally once daily for 21 days, followed by 7 placebo days.
Terminal half-life: norethindrone 7-8 hours, ethinyl estradiol 13-27 hours; clinical context: steady-state achieved in 3-5 half-lives
Levonorgestrel: terminal elimination half-life 25±10 hours; ethinyl estradiol: 13±7 hours. Clinical context: steady-state concentrations achieved within 5-7 days; contraceptive efficacy requires consistent daily dosing.
Norethindrone is metabolized primarily via reduction and conjugation; ethinyl estradiol is metabolized via CYP3A4 and undergoes glucuronidation. Both undergo enterohepatic circulation.
Ethinyl estradiol: primarily metabolized by CYP3A4; undergoes sulfation and glucuronidation. Desogestrel: rapidly converted to active metabolite etonogestrel via CYP2C9 and CYP2C19; further metabolism by CYP3A4.
Renal: ~60% as metabolites, biliary/fecal: ~40% as glucuronide conjugates
Renal excretion of metabolites and unchanged drug: ~30% (levonorgestrel) and ~20% (ethinyl estradiol) in urine; biliary/fecal elimination: ~40-50% as conjugates and metabolites.
Norethindrone: 80% bound to albumin and SHBG; ethinyl estradiol: 97% bound to albumin
Levonorgestrel: 98-99% bound to sex hormone-binding globulin (SHBG) and albumin; ethinyl estradiol: 98% bound to albumin.
Norethindrone: 4 L/kg, indicates extensive tissue distribution; ethinyl estradiol: 4-5 L/kg
Levonorgestrel: Vd ~1.8 L/kg (suggesting extensive tissue distribution). Ethinyl estradiol: Vd ~2.4 L/kg.
Oral: norethindrone ~65%, ethinyl estradiol ~40-45% due to first-pass metabolism
Oral bioavailability: levonorgestrel ~100% (nearly complete); ethinyl estradiol ~45-50% (first-pass hepatic metabolism).
No specific GFR-based dose adjustments recommended; use with caution in renal impairment due to potential fluid retention.
No dose adjustment required for mild to moderate renal impairment. Contraindicated in severe renal disease or acute renal failure due to potential fluid retention.
Contraindicated in Child-Pugh class B or C (severe hepatic impairment) or active liver disease. For mild impairment (Child-Pugh A), use with caution and monitor liver function.
Contraindicated in severe hepatic dysfunction (Child-Pugh class B or C). Use caution in mild to moderate impairment (Child-Pugh A); monitor liver enzymes.
Not indicated for use before menarche; dosing for postmenarchal adolescents same as adult.
Not indicated for use before menarche. For postmenarchal adolescents, same dosing as adults (1 tablet daily, 21/7 regimen) after evaluation of risks.
Not indicated for use in postmenopausal women; no geriatric dosing established due to lack of indication.
Not indicated for postmenopausal women. No specific geriatric dosing; consider increased risk of thromboembolism, cardiovascular disease, and metabolic effects in older women of reproductive age.
Cigarette smoking increases the risk of serious cardiovascular events from combination oral contraceptives. This risk increases with age and heavy smoking (≥15 cigarettes/day) and is significant in women over 35. Women over 35 who smoke should not use this product.
Cigarette smoking increases risk of serious cardiovascular events from combined oral contraceptives. Risk increases with age (especially >35 years) and with number of cigarettes smoked. Women who use combined hormonal contraceptives should be strongly advised not to smoke.
Thrombotic disorders (venous thromboembolism, arterial thromboembolism, stroke, myocardial infarction),Cerebrovascular disease,Hepatic neoplasia (benign and malignant),Gallbladder disease,Hypertension,Carbohydrate and lipid metabolism effects,Ocular lesions (retinal thrombosis, optic neuritis),Headache (including migraine),Breakthrough bleeding and spotting,Depression,Malignant neoplasms (breast, cervical),Effect on pregnancies (fetal harm if used during pregnancy),Lactation (may decrease milk production),Hereditary angioedema,Chloasma,Laboratory test interference
Thrombotic disorders: risk of venous thromboembolism (VTE), stroke, myocardial infarction; discontinue if thrombotic event occurs.,Hepatic disease: discontinue if jaundice or liver function abnormalities develop.,Hypertension: monitor blood pressure; discontinue if uncontrolled.,Carbohydrate metabolism: may affect glucose tolerance; monitor diabetic patients.,Depression: discontinue if significant depression occurs.,Gallbladder disease: increased risk of cholelithiasis.
Thrombophlebitis or thromboembolic disorders,Cerebrovascular or coronary artery disease,Known or suspected breast cancer,Undiagnosed abnormal genital bleeding,Pregnancy or suspected pregnancy,Benign or malignant liver tumors, or active liver disease,Hypersensitivity to any component,Women over 35 who smoke cigarettes
Thrombophlebitis or thromboembolic disorders (current or history),Cerebrovascular or coronary artery disease (current or history),Known or suspected breast carcinoma,Estrogen-dependent neoplasia (known or suspected),Undiagnosed abnormal genital bleeding,Cholestatic jaundice of pregnancy or jaundice with prior pill use,Hepatic adenoma or carcinoma (known or suspected),Pregnancy (known or suspected),Hypersensitivity to any component
Avoid grapefruit juice as it may alter metabolism; no other significant food interactions reported.
No significant food interactions. Alcohol does not affect efficacy but may increase risk of adverse effects such as nausea. Grapefruit juice has no known interaction. Avoid excessive alcohol consumption due to potential hepatotoxicity.
Pregnancy category X. Contraindicated in pregnancy. First trimester: Increased risk of congenital anomalies, including cardiac and limb defects, due to progestin and estrogen exposure. Second and third trimesters: Risk of feminization of male fetus, urogenital sinus abnormalities, and clitoral hypertrophy from progestin (norethindrone). Post-fertilization: Disruption of fetal development.
ALTAVERA contains ethinyl estradiol and levonorgestrel. First trimester: Inadvertent exposure during organogenesis is associated with a very low absolute risk of cardiovascular defects (relative risk 1.2-1.4) and no consistent increase in other major malformations. Second and third trimesters: No known teratogenic effects, but theoretical risks from estrogenic effects (e.g., feminization of male fetus). Postnatal: No increased risk of long-term developmental effects from pregnancy exposure.
Norethindrone and ethinyl estradiol are excreted in breast milk in small amounts (M/P ratio approximately 0.5-1.0 for norethindrone). May reduce milk production and quality. Use only if clearly needed and with caution, as long-term effects on infant are unknown. Typically not recommended during breastfeeding.
Combined oral contraceptives may reduce milk production and quality, especially in early lactation. Ethinyl estradiol transfers into breast milk at low levels (M/P ratio approximately 0.1-0.2), excluding clinical effects in term infants. Levonorgestrel transfer is minimal (M/P ratio ~0.2-0.4). Use is generally avoided in breastfeeding women, especially during the first 6 weeks postpartum. Progestin-only methods are preferred.
No dose adjustments applicable as drug is contraindicated in pregnancy. No studies indicate need for dose change during pregnancy due to pharmacokinetic changes, as use is not recommended.
Contraindicated in pregnancy. No dose adjustment recommended because use is discontinued upon confirmed or suspected pregnancy. Pharmacokinetic changes in pregnancy (e.g., increased hepatic clearance, altered binding proteins) are not relevant for this indication.
Monitor for thromboembolic events, especially in smokers over 35. Use as part of a combined oral contraceptive regimen; may cause breakthrough bleeding. Check for drug interactions with rifampin, carbamazepine, and certain antibiotics.
ALTAVERA is a combined oral contraceptive (COC) containing ethinylestradiol and levonorgestrel. It inhibits ovulation via suppression of gonadotropins. Counsel patients to take at the same time daily to maintain efficacy. Missed pill management: if missed within 12 hours, take immediately; if >12 hours, take last missed pill and use backup contraception for 7 days. Be aware of increased VTE risk, especially in smokers over 35. May reduce effectiveness of lamotrigine; monitor seizure control. Initiate on the first day of menses or first Sunday after onset.
Take at the same time daily to maintain consistent hormone levels.,Report signs of blood clots (leg pain, chest pain, sudden headache) immediately.,Use backup contraception if you miss a dose or start a new medication.,Do not smoke while taking this medication, especially if over 35 years old.,This medication does not protect against sexually transmitted diseases.
Take one tablet daily at the same time each day, with or without food.,If you miss a pill by less than 12 hours, take it as soon as you remember. If more than 12 hours, take the missed pill and use a backup method (e.g., condoms) for the next 7 days.,Smoking increases your risk of serious cardiovascular side effects, especially if you are over 35 years old. Do not smoke while taking this medication.,Seek immediate medical attention if you experience sudden severe headache, chest pain, leg pain/swelling, or vision changes (symptoms of blood clots).,This medication does not protect against HIV or other sexually transmitted infections.,If you are taking lamotrigine or other anticonvulsants, tell your doctor; your seizure medication may be less effective.,Store at room temperature away from moisture and heat.
No interactions on record
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about NORINYL vs ALTAVERA, answered by our medical review team.
NORINYL is a Combined Oral Contraceptive that works by Combination of norethindrone (progestin) and ethinyl estradiol (estrogen) provides contraception by inhibiting gonadotropin secretion via negative feedback on the hypothalamic-pituitary-ovarian axis, suppressing ovulation, increasing cervical mucus viscosity, and altering endometrial receptivity.. ALTAVERA is a Combined Oral Contraceptive that works by Combination of ethinyl estradiol and desogestrel: ethinyl estradiol suppresses gonadotropin release, inhibiting ovulation; desogestrel (progestin) causes cervical mucus thickening and endometrial atrophy, preventing implantation.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between NORINYL and ALTAVERA depend on the specific clinical indication. These are both Combined Oral Contraceptive agents and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of NORINYL is: One tablet (norethindrone 1 mg/ethinyl estradiol 0.035 mg) orally once daily for 21 days, followed by 7 placebo tablets. For first cycle, start on first Sunday after menstruation begins or on day 1 of menstrual cycle.. The standard adult dose of ALTAVERA is: 1 tablet (ethinyl estradiol 0.03 mg / levonorgestrel 0.15 mg) orally once daily for 21 days, followed by 7 placebo days.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between NORINYL and ALTAVERA in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. NORINYL is classified as Category C. Pregnancy category X. Contraindicated in pregnancy. First trimester: Increased risk of congenital anomalies, including cardiac and limb defects, due to progestin and estrogen expos. ALTAVERA is classified as Category C. ALTAVERA contains ethinyl estradiol and levonorgestrel. First trimester: Inadvertent exposure during organogenesis is associated with a very low absolute risk of cardiovascular def. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.