Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
OVCON-35 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 contraceptive; suppresses gonadotropin release, inhibiting ovulation, and increases cervical mucus viscosity, impeding sperm penetration.
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 (35 mcg ethinyl estradiol and 0.4 mg norethindrone) orally once daily.
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.
Ethinyl estradiol: 5-18 hours (mean ~12 hours, biphasic); norethindrone: 5-14 hours (mean ~8 hours). Terminal half-life relevant for once-daily 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 is primarily metabolized by CYP3A4; norethindrone is metabolized via reduction and sulfate conjugation, partly involving CYP3A4.
Ethinyl estradiol: primarily hepatic via CYP3A4; norethindrone: hepatic reduction and sulfate conjugation.
Renal 60% (metabolites, glucuronide conjugates), fecal 10%, biliary 5%, remainder via other pathways.
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%).
Ethinyl estradiol: 97-98% (mainly albumin, SHBG); norethindrone: 90-95% (albumin, SHBG).
Norethindrone: 61% bound to albumin and SHBG; ethinyl estradiol: 97-98% bound to albumin.
Ethinyl estradiol: 2-4 L/kg; norethindrone: 4-6 L/kg. Large Vd indicates extensive tissue distribution.
Norethindrone: 3.8-4.5 L/kg; ethinyl estradiol: 2.0-4.0 L/kg. Large Vd indicates extensive tissue distribution.
Ethinyl estradiol: ~38-48% (first-pass metabolism); norethindrone: ~64% (range 47-73%).
Oral: Norethindrone ~64%, ethinyl estradiol ~38-48% (due to first-pass metabolism).
No dose adjustment required for mild-to-moderate renal impairment. Contraindicated in severe renal impairment (GFR <30 m L/min) due to risk of hyperkalemia.
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 severe hepatic disease (Child-Pugh Class C) and active liver disease. Use with caution in Child-Pugh Class A or B; dose adjustment not established.
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 not established in children under 18 years. Postmenarchal adolescents: same as adult dosing, but weigh risks vs. benefits.
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 typically used in postmenopausal women. Contraindicated in women over 60 due to increased risk of thromboembolic events and hypertension.
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 from combination oral contraceptive use. This risk increases with age and with heavy smoking (≥15 cigarettes/day). Women over 35 who smoke should not use combination oral contraceptives.
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, and hepatic neoplasia,Discontinue if jaundice, visual disturbances, or migraine headaches develop,May cause fluid retention; use with caution in conditions that might be aggravated by fluid retention,May decrease glucose tolerance; monitor diabetic patients,May cause elevation in blood pressure,Hereditary angioedema may be exacerbated
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 or thromboembolic disorders,Cerebrovascular or coronary artery disease,Known or suspected breast cancer,Estrogen-dependent neoplasia,Undiagnosed abnormal genital bleeding,Pregnancy,Active liver disease or benign/malignant liver tumors,Heavy smoking in women over 35
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 specific food interactions. However, grapefruit juice may increase ethinyl estradiol levels by inhibiting CYP3A4; avoid excessive consumption. Cranberry juice may increase warfarin effect if taken concurrently, but no direct interaction with OVCON-35. Take with food or milk to reduce nausea.
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.
FDA Pregnancy Category X. First trimester: increased risk of neural tube defects, congenital heart defects, and limb reduction defects. Second and third trimesters: fetal feminization in males, vaginal adenosis in females, and other urogenital anomalies. Postnatal: increased risk of neurodevelopmental issues.
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).
Contraindicated in breastfeeding. Estrogens and progestins are excreted in breast milk. M/P ratio not established. May reduce milk production and quality.
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 in pregnancy; no dose adjustment applies. Use is contraindicated once pregnancy is confirmed. Discontinue immediately.
Contraindicated in pregnancy; no dose adjustments applicable. Discontinue medication immediately upon pregnancy detection.
OVCON-35 is a combined oral contraceptive (COC) containing norethindrone 0.4 mg and ethinyl estradiol 35 mcg. It has higher progestin dose relative to estrogen, making it suitable for women with estrogen-related side effects. Monitor for breakthrough bleeding, particularly in early cycles. Contraindicated in women with BMI > 35 due to increased thromboembolic risk. Consider interaction with CYP450 inducers (e.g., rifampin) which may reduce contraceptive efficacy. Use with caution in migraine with aura due to stroke risk.
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 tablet daily at the same time to maintain hormone levels and prevent pregnancy.,If you miss a pill, follow the instructions in the package insert or consult your healthcare provider. Missing pills increases pregnancy risk.,Common side effects include nausea, breast tenderness, headache, and breakthrough bleeding. These often improve after 2-3 cycles.,This medication does not protect against sexually transmitted infections (STIs). Use barrier protection.,Inform your doctor of all medications, especially antibiotics, anticonvulsants, or St. John's Wort, as they may reduce effectiveness.,Seek immediate medical attention if you experience severe leg pain, chest pain, sudden shortness of breath, or severe headache (signs of blood clots or stroke).,Do not smoke while using this medication, especially if over 35 years old; smoking increases risk of serious cardiovascular side effects.
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 OVCON-35 vs ALYACEN 1/35, answered by our medical review team.
OVCON-35 is a Oral Contraceptive that works by Combination estrogen-progestin contraceptive; suppresses gonadotropin release, inhibiting ovulation, and increases cervical mucus viscosity, impeding sperm penetration.. 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 OVCON-35 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 OVCON-35 is: One tablet (35 mcg ethinyl estradiol and 0.4 mg norethindrone) orally once daily.. 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 OVCON-35 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. OVCON-35 is classified as Category C. FDA Pregnancy Category X. First trimester: increased risk of neural tube defects, congenital heart defects, and limb reduction defects. Second and third trimesters: fetal feminizat. 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.