Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
NORTREL 7/7/7 vs ALYACEN 1/35
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Combination estrogen-progestin oral contraceptive. Suppresses gonadotropin release, inhibiting ovulation. Increases cervical mucus viscosity and alters endometrial receptivity.
Combination hormonal contraceptive: ethinyl estradiol suppresses gonadotropin release via negative feedback on hypothalamic-pituitary axis; norethindrone induces progestational effects including cervical mucus thickening and endometrial changes, inhibiting ovulation and sperm penetration.
Prevention of pregnancy
Prevention of pregnancy
One tablet orally once daily, taken at the same time each day. Each tablet contains norethindrone 0.5 mg/ethinyl estradiol 35 mcg for days 1-7, norethindrone 0.75 mg/ethinyl estradiol 35 mcg for days 8-14, and norethindrone 1 mg/ethinyl estradiol 35 mcg for days 15-21, followed by 7 placebo tablets.
One tablet (norethindrone 1 mg and ethinyl estradiol 35 mcg) orally once daily for 21 consecutive days, followed by 7 days of placebo or no tablets.
Norelgestromin terminal half-life is approximately 28 hours; ethinyl estradiol terminal half-life is approximately 17 hours. The extended half-life supports once-weekly dosing.
Norethindrone: 8-11 hours (terminal); ethinyl estradiol: 10-20 hours (terminal). The half-life supports once-daily dosing for oral contraceptive efficacy.
Ethinyl estradiol: primarily metabolized by CYP3A4; undergoes first-pass metabolism. Norethindrone: metabolized by reduction and conjugation; primarily via CYP3A4.
Ethinyl estradiol: primarily hepatic via CYP3A4; norethindrone: hepatic reduction and sulfate conjugation.
Renal excretion of metabolites (primarily ethinyl estradiol and norelgestromin conjugates) accounts for approximately 50% of elimination; fecal/biliary excretion accounts for the remainder (about 35-40% fecal, 10-15% biliary).
Renal excretion of metabolites (primarily ethinyl estradiol and norethindrone conjugates) accounts for approximately 50-60% of elimination; fecal excretion accounts for 30-40%. Unchanged drug excretion is minimal (<5%).
Norelgestromin is 99% bound primarily to albumin and sex hormone-binding globulin; ethinyl estradiol is 98% bound primarily to albumin.
Norethindrone: 61% bound to albumin and SHBG; ethinyl estradiol: 97-98% bound to albumin.
Norelgestromin apparent Vd/F is approximately 2.1 L/kg; ethinyl estradiol apparent Vd/F is approximately 5.5 L/kg, indicating extensive tissue distribution.
Norethindrone: 3.8-4.5 L/kg; ethinyl estradiol: 2.0-4.0 L/kg. Large Vd indicates extensive tissue distribution.
Transdermal bioavailability of norelgestromin and ethinyl estradiol is approximately 60-65% relative to oral administration due to avoidance of first-pass metabolism.
Oral: Norethindrone ~64%, ethinyl estradiol ~38-48% (due to first-pass metabolism).
No dose adjustment recommended for mild to moderate renal impairment. Contraindicated in severe renal impairment or acute renal failure due to potential for decreased drug elimination and hormonal alterations.
No dose adjustment required for mild to moderate renal impairment. Contraindicated in severe renal impairment or acute renal failure due to potential fluid retention and electrolyte disturbances.
Contraindicated in acute hepatic disease or severe hepatic insufficiency (Child-Pugh class C). For Child-Pugh class A or B, use with caution; consider alternative contraception due to possible impaired hormone metabolism. No specific dose adjustment guidelines available.
Contraindicated in patients with hepatic impairment, including Child-Pugh class B or C, due to impaired metabolism of estrogen and progestin. Not recommended in patients with active liver disease or history of liver tumors.
Safety and efficacy in postmenarchal pediatric patients have been established. Dose is the same as for adults: one tablet orally once daily following the 28-day regimen.
Not indicated for use before menarche. For postmenarchal adolescents, same dosing as adults. Safety and efficacy established for contraception; weight-based dosing not applicable.
Not indicated for use in postmenopausal women. No studies in geriatric population; use is not appropriate due to lack of need for contraception.
Not indicated for use after menopause due to lack of benefit and increased risks (e.g., cardiovascular, thromboembolic events). If used, monitor for fluid retention, hypertension, and glucose intolerance.
Cigarette smoking increases risk of serious cardiovascular events. Use is contraindicated in women over 35 who smoke.
Cigarette smoking increases risk of serious cardiovascular events from combined oral contraceptives. Risk increases with age and heavy smoking (≥15 cigarettes/day). Women over 35 who smoke should not use this product.
Increased risk of thromboembolic disorders, myocardial infarction, stroke, hepatic neoplasia, gallbladder disease. Discontinue if jaundice, visual disturbances, or migraine occurs. Blood pressure should be monitored.
Thrombotic disorders (e.g., DVT, PE, stroke, MI),Cerebrovascular disease,Hepatic neoplasia,Gallbladder disease,Hypertension,Carbohydrate and lipid effects,Ocular lesions,Hereditary angioedema,Chloasma,Menstrual irregularities,Pregnancy exclusion prior to initiation
Thrombophlebitis, thromboembolic disorders, cerebral vascular disease, coronary artery disease, known or suspected pregnancy, undiagnosed abnormal genital bleeding, known or suspected breast cancer, liver tumor or active liver disease, hypersensitivity to components, and women over 35 who smoke.
Venous or arterial thrombotic/thromboembolic disease (current or history),Cerebrovascular disease,Coronary artery disease,Known or suspected breast cancer,Endometrial or other estrogen-dependent neoplasia,Undiagnosed abnormal genital bleeding,Cholestatic jaundice of pregnancy or jaundice with prior pill use,Hepatic adenoma or carcinoma,Known or suspected pregnancy,Hypersensitivity to any component,Smoking in women over 35
No significant food interactions. Grapefruit juice may slightly increase estrogen exposure but not considered clinically relevant. Avoid herbal supplements such as St. John's wort, which can reduce contraceptive efficacy.
No significant food interactions. Grapefruit juice may increase estrogen levels, but clinically not a concern. Avoid excessive alcohol, which may impair liver function and increase estrogen exposure. Maintain a healthy diet, as weight gain is possible.
First trimester: No known association with major congenital anomalies based on population data. However, exposure to ethinyl estradiol and norethindrone acetate is not recommended during pregnancy due to theoretical risks from hormonal exposure. Second and third trimesters: Not indicated for use; hormonal contraceptives should be discontinued if pregnancy occurs. No evidence of fetal harm from inadvertent use early in pregnancy.
Pregnancy category X. Use of ALYACEN 1/35 (norethindrone/ethinyl estradiol) is contraindicated during pregnancy. First trimester: Increased risk of congenital anomalies, including cardiovascular defects and limb reduction defects. Second/third trimesters: Potential for urogenital abnormalities and feminization of male fetus. Exposure is associated with subsequent development of clear cell adenocarcinoma of vagina/cervix in female offspring (DES-related).
Combined hormonal contraceptives may reduce milk production and pass into breast milk. The M/P ratio for ethinyl estradiol is approximately 0.3-0.5; for norethindrone, minimal transfer. Use is generally not recommended during breastfeeding, especially in the early postpartum period. Alternative contraception advised.
Small amounts of contraceptive steroids and/or metabolites have been identified in breast milk. M/P ratio: Not specifically determined for this combination; ethinyl estradiol M/P ratio ~0.02-0.04. Use may reduce milk production and quality. Breastfeeding not recommended during use. Alternative contraception advised.
Contraindicated during pregnancy. No pharmacokinetic studies in pregnant women; no dose adjustments needed as drug is discontinued. Standard dosing for non-pregnant women: 7 tablets of 0.035 mg ethinyl estradiol/0.5 mg norethindrone, then 7 tablets of 0.035 mg EE/0.75 mg NE, then 7 tablets of 0.035 mg EE/1 mg NE.
Contraindicated in pregnancy; no dose adjustments applicable. Discontinue medication immediately upon pregnancy detection.
NORTREL 7/7/7 is a triphasic oral contraceptive. The 7/7/7 dosing (7 days of 35 mcg EE/0.5 mg norethindrone, 7 days of 35 mcg EE/0.75 mg norethindrone, 7 days of 35 mcg EE/1 mg norethindrone) mimics natural cycle. Missed dose management: if missed one active pill, take as soon as remembered; if missed two or more, use backup contraception for 7 days and consider emergency contraception. Breakthrough bleeding is common in first 3 cycles. Drug interactions: rifampin, certain anticonvulsants, and some antibiotics may reduce efficacy. Contraindicated in women with migraines with aura, history of DVT/PE, active liver disease, or breast cancer. Monitor blood pressure at baseline and follow-up.
ALYACEN 1/35 is a combination oral contraceptive containing ethinyl estradiol 35 mcg and norgestimate 1 mg. It is indicated for the prevention of pregnancy and for the treatment of moderate acne vulgaris in females ≥15 years of age who desire an oral contraceptive. Monitor for thromboembolic events, especially in smokers over 35 or those with migraine with aura. Use with caution in patients with liver impairment or history of cholestatic jaundice. The pill-free interval should not exceed 7 days; missed pills increase ovulation risk. Consider non-hormonal backup if vomiting or diarrhea occurs within 4 hours of dosing.
Take one pill daily at the same time each day, following the 7/7/7 sequence.,Missed pill instructions: if you miss one active pill, take it as soon as you remember and continue the pack; if you miss two or more active pills, take the most recent missed pill, discard others, use backup contraception for 7 days, and consider emergency contraception.,Common side effects include nausea, breast tenderness, breakthrough bleeding, and mood changes; these often improve after 3 cycles.,Seek emergency care if you experience leg pain/swelling, chest pain, sudden severe headache, or vision changes, which may signal a blood clot.,Smoking increases the risk of serious cardiovascular side effects, especially if you are over 35 years old.,Tell your doctor about all medications you take, including antibiotics and herbal supplements like St. John's wort.,If you miss a period, take a pregnancy test and contact your doctor.
Take one tablet daily at the same time each day; do not skip doses.,Use an additional non-hormonal contraceptive (e.g., condoms) if you miss a pill, have vomiting, or diarrhea.,Smoking while on this pill increases the risk of blood clots and stroke, especially if you are over 35.,Contact your healthcare provider immediately if you have chest pain, leg pain/swelling, sudden vision changes, or severe headache.,This medication does not protect against HIV or other sexually transmitted infections.,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 NORTREL 7/7/7 vs ALYACEN 1/35, answered by our medical review team.
NORTREL 7/7/7 is a Oral Contraceptive that works by Combination estrogen-progestin oral contraceptive. Suppresses gonadotropin release, inhibiting ovulation. Increases cervical mucus viscosity and alters endometrial receptivity.. ALYACEN 1/35 is a Oral Contraceptive that works by Combination hormonal contraceptive: ethinyl estradiol suppresses gonadotropin release via negative feedback on hypothalamic-pituitary axis; norethindrone induces progestational effects including cervical mucus thickening and endometrial changes, inhibiting ovulation and sperm penetration.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between NORTREL 7/7/7 and ALYACEN 1/35 depend on the specific clinical indication. These are both 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 NORTREL 7/7/7 is: One tablet orally once daily, taken at the same time each day. Each tablet contains norethindrone 0.5 mg/ethinyl estradiol 35 mcg for days 1-7, norethindrone 0.75 mg/ethinyl estradiol 35 mcg for days 8-14, and norethindrone 1 mg/ethinyl estradiol 35 mcg for days 15-21, followed by 7 placebo tablets.. The standard adult dose of ALYACEN 1/35 is: One tablet (norethindrone 1 mg and ethinyl estradiol 35 mcg) orally once daily for 21 consecutive days, followed by 7 days of placebo or no tablets.. 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 NORTREL 7/7/7 and ALYACEN 1/35 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. NORTREL 7/7/7 is classified as Category C. First trimester: No known association with major congenital anomalies based on population data. However, exposure to ethinyl estradiol and norethindrone acetate is not recommended . ALYACEN 1/35 is classified as Category C. Pregnancy category X. Use of ALYACEN 1/35 (norethindrone/ethinyl estradiol) is contraindicated during pregnancy. First trimester: Increased risk of congenital anomalies, including . Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.