Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
OVRAL-28 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 oral contraceptive: suppresses gonadotropin release via estrogen and progestin, inhibiting ovulation, thickening cervical mucus, and altering endometrial lining.
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,Treatment of moderate acne vulgaris in females aged ≥15 years who have no known contraindications and have achieved menarche
Prevention of pregnancy
One tablet (norgestrel 0.3 mg, ethinyl estradiol 0.03 mg) orally once daily for 21 consecutive days, followed by 7 days of placebo.
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: terminal half-life 13-27 hours (mean ~17 hours); norgestrel: terminal half-life 11-45 hours (mean ~24 hours). Clinical context: steady-state reached within 5-7 days; accumulation minimal with 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: primarily hepatic via CYP3A4, undergoes first-pass metabolism; norgestrel: hepatic reduction and conjugation, partially via CYP3A4.
Ethinyl estradiol: primarily hepatic via CYP3A4; norethindrone: hepatic reduction and sulfate conjugation.
Renal: ~40% as metabolites; fecal: ~60% via biliary excretion, primarily as glucuronide and sulfate conjugates.
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% bound, primarily to albumin; norgestrel: 93-95% bound, primarily to sex hormone-binding globulin (SHBG) and albumin.
Norethindrone: 61% bound to albumin and SHBG; ethinyl estradiol: 97-98% bound to albumin.
Ethinyl estradiol: 2.5-4.0 L/kg; norgestrel: 2.0-3.5 L/kg. High Vd indicates extensive tissue distribution and binding.
Norethindrone: 3.8-4.5 L/kg; ethinyl estradiol: 2.0-4.0 L/kg. Large Vd indicates extensive tissue distribution.
Oral: ethinyl estradiol ~40-50% (due to first-pass metabolism); norgestrel ~60-70% (variable due to presystemic metabolism).
Oral: Norethindrone ~64%, ethinyl estradiol ~38-48% (due to first-pass metabolism).
No dosage adjustment required for mild to moderate renal impairment. Insufficient data for severe renal impairment (Cr Cl <30 m L/min); use with caution due to potential fluid retention.
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 hepatitis, hepatic adenomas, or severe cirrhosis (Child-Pugh class C). For mild to moderate impairment (Child-Pugh A or B), consider alternative therapy; if used, monitor liver function closely and reduce dose if tolerated.
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.
Not indicated for use before menarche. For postmenarchal adolescents, same dosing as adults (one tablet daily).
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 after menopause. No specific dosing adjustments provided for elderly patients; consider increased risk of thromboembolic events and cardiovascular disease.
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. Combination oral contraceptives are 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 thrombotic disorders (venous thromboembolism, stroke, MI),Elevated blood pressure,Gallbladder disease,Hepatic neoplasia,Glucose intolerance,Retinal thrombosis,Depression
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
Current or history of thrombotic disorders,Known or suspected breast carcinoma,Undiagnosed abnormal genital bleeding,Hepatic adenoma or carcinoma,Known or suspected pregnancy,Hypersensitivity to any component
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 known; however, grapefruit juice may increase ethinyl estradiol exposure. High-fat meals may slightly reduce absorption but not clinically significant. Advise consistent intake with food to minimize gastrointestinal upset.
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.
Pregnancy category X. First trimester: risk of congenital malformations (neural tube defects, cardiovascular anomalies) and spontaneous abortion. Second and third trimesters: associated with fetal adrenal suppression, hepatic impairment, and potential for masculinization of female genitalia.
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 during breastfeeding. Estrogens and progestins are excreted in human milk in low concentrations (M/P ratio not established). Potential for adverse effects on the infant including jaundice and breast enlargement.
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 adjustments applicable. Discontinue immediately upon pregnancy confirmation.
Contraindicated in pregnancy; no dose adjustments applicable. Discontinue medication immediately upon pregnancy detection.
Ovral-28 is a combination oral contraceptive containing norgestrel and ethinyl estradiol. It is dosed as 28-day regimen with 21 active pills and 7 placebo. Patients should be counseled about the risk of thromboembolism, especially if over 35 years old and smoking. Efficacy may be reduced with concurrent use of certain anticonvulsants (e.g., phenytoin, carbamazepine) and antibiotics (e.g., rifampin). Instruct patients to take at the same time daily to maintain consistent serum levels. Missed doses require backup contraception; refer to package insert for missed pill algorithm.
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, preferably with a meal to reduce nausea.,Do not skip pills; if a pill is missed, follow the instructions in the patient information leaflet and use backup contraception as directed.,Smoking increases the risk of serious cardiovascular side effects, especially in women over 35. Avoid smoking while on this medication.,Use backup contraception (like condoms) when starting the pill and if you miss pills or take certain other medications.,Common side effects include nausea, headache, breast tenderness, and breakthrough bleeding, which often improve after 2-3 months.,Seek medical attention immediately if you experience symptoms of blood clots: sudden chest pain, shortness of breath, leg pain/swelling, or sudden severe headache.,This medication does not protect against HIV or other sexually transmitted infections.
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 OVRAL-28 vs ALYACEN 1/35, answered by our medical review team.
OVRAL-28 is a Oral Contraceptive that works by Combination oral contraceptive: suppresses gonadotropin release via estrogen and progestin, inhibiting ovulation, thickening cervical mucus, and altering endometrial lining.. 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 OVRAL-28 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 OVRAL-28 is: One tablet (norgestrel 0.3 mg, ethinyl estradiol 0.03 mg) orally once daily for 21 consecutive days, followed by 7 days of placebo.. 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 OVRAL-28 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. OVRAL-28 is classified as Category C. Pregnancy category X. First trimester: risk of congenital malformations (neural tube defects, cardiovascular anomalies) and spontaneous abortion. Second and third trimesters: assoc. 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.