Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
OGESTREL 0.5/50-28 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 estrogen-progestin contraceptive; suppresses gonadotropins (FSH, LH) via negative feedback on hypothalamic-pituitary axis, inhibiting ovulation; increases cervical mucus viscosity and alters endometrial development.
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 (females ≥15 years, for formulations with at least 30 mcg ethinyl estradiol and norgestimate/desogestrel)
Prevention of pregnancy
One tablet (norgestrel 0.5 mg/ethinyl estradiol 50 mcg) orally once daily for 28-day cycle.
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.
Norgestrel: ~45 hours (range 24-56 h) enabling once-daily dosing; Ethinyl estradiol: ~17 hours (range 10-27 h).
Norethindrone: 8-11 hours (terminal); ethinyl estradiol: 10-20 hours (terminal). The half-life supports once-daily dosing for oral contraceptive efficacy.
Norgestrel and ethinyl estradiol are metabolized primarily via cytochrome P450 3A4 (CYP3A4) in the liver; undergo first-pass metabolism; ethinyl estradiol also undergoes conjugation (sulfation, glucuronidation).
Ethinyl estradiol: primarily hepatic via CYP3A4; norethindrone: hepatic reduction and sulfate conjugation.
Renal: 50-60% as metabolites (glucuronide and sulfate conjugates of norgestrel and ethinyl estradiol); Fecal: 30-40% via biliary elimination; Unchanged drug: <1%.
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%).
Norgestrel: ~97% bound to sex hormone-binding globulin (SHBG) and albumin; Ethinyl estradiol: ~98% bound to albumin, with 2% free (active).
Norethindrone: 61% bound to albumin and SHBG; ethinyl estradiol: 97-98% bound to albumin.
Norgestrel: ∼4 L/kg (range 3-5 L/kg), indicating extensive tissue distribution; Ethinyl estradiol: ∼2 L/kg (range 1.5-3 L/kg), reflecting distribution to reproductive tissues and liver.
Norethindrone: 3.8-4.5 L/kg; ethinyl estradiol: 2.0-4.0 L/kg. Large Vd indicates extensive tissue distribution.
Oral: Norgestrel ~90-100% (high first-pass metabolism but minimal systemic loss); Ethinyl estradiol ~40-50% due to first-pass metabolism (conjugation in gut wall and liver).
Oral: Norethindrone ~64%, ethinyl estradiol ~38-48% (due to first-pass metabolism).
No dose adjustment required for mild to moderate renal impairment. Not recommended in severe renal impairment (Cr Cl <30 m L/min) or ESRD due to lack of safety data.
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 Child-Pugh class B and C cirrhosis. For mild hepatic impairment (Child-Pugh A), use with caution; no specific dose adjustment studied.
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 children; use only after menarche. Postmenarcheal adolescents: same as adult dosing (one tablet daily) once menses established.
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 women ≥65 years; no geriatric-specific dosing recommended. Consider alternative therapies due to increased thrombosis risk and reduced bone density with prolonged use.
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 contraceptives. Risk increases with age (>35 years) and number of cigarettes smoked. 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 and heavy smoking (≥15 cigarettes/day). Women over 35 who smoke should not use this product.
Thrombotic disorders (venous thromboembolism, arterial thromboembolism, stroke, MI),Cerebrovascular disease,Hepatic neoplasia,Gallbladder disease,Hypertension,Carbohydrate/lipid effects,Headache/migraine,Vaginal bleeding irregularities,Depression,Hereditary angioedema
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
Known or suspected pregnancy,Current or history of venous thromboembolism (VTE) or arterial thromboembolism (ATE),Active liver disease or hepatic tumors,Undiagnosed abnormal genital bleeding,Known or suspected breast cancer or other estrogen-sensitive neoplasia,Hypersensitivity to any component,Cigarette smoking in women >35 years,Uncontrolled hypertension,Migraine with aura in women ≥35 years
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 increase estrogen levels, but clinically negligible. Avoid high-fat meals if taking with a progestin-only pill (not applicable here).
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.
No increased risk of birth defects has been observed in clinical studies for norgestrel/ethinyl estradiol. Use during pregnancy is contraindicated as hormonal contraceptives are not indicated during gestation. There is no evidence of teratogenicity when inadvertently taken during early 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).
Small amounts of norgestrel and ethinyl estradiol are excreted in breast milk. M/P ratio not established. Can reduce milk production and quality. Use is generally not recommended during breastfeeding; alternative methods should be considered.
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.
Not applicable; contraindicated in pregnancy. No pharmacokinetic studies during pregnancy; no dose adjustment recommendation exists.
Contraindicated in pregnancy; no dose adjustments applicable. Discontinue medication immediately upon pregnancy detection.
OGESTREL 0.5/50-28 contains norgestrel 0.5 mg and ethinyl estradiol 50 mcg. Its higher estrogen dose (50 mcg) increases thromboembolic risk; avoid in smokers over 35. Use as emergency contraception off-label. Missed pill management: if one pill missed, take as soon as remembered; if two or more missed, use backup contraception. Withdrawal bleeding typically occurs during the 7 placebo pills.
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; do not skip doses.,During the 7 placebo pills, you will have a withdrawal bleed; this is normal.,Use backup contraception (e.g., condoms) if you miss 2 or more pills.,Do not smoke while taking this medication, especially if over age 35.,Report any signs of blood clots: leg pain/swelling, chest pain, shortness of breath, sudden headache or vision changes.,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 OGESTREL 0.5/50-28 vs ALYACEN 1/35, answered by our medical review team.
OGESTREL 0.5/50-28 is a Oral Contraceptive that works by Combination estrogen-progestin contraceptive; suppresses gonadotropins (FSH, LH) via negative feedback on hypothalamic-pituitary axis, inhibiting ovulation; increases cervical mucus viscosity and alters endometrial development.. 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 OGESTREL 0.5/50-28 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 OGESTREL 0.5/50-28 is: One tablet (norgestrel 0.5 mg/ethinyl estradiol 50 mcg) orally once daily for 28-day cycle.. 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 OGESTREL 0.5/50-28 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. OGESTREL 0.5/50-28 is classified as Category C. No increased risk of birth defects has been observed in clinical studies for norgestrel/ethinyl estradiol. Use during pregnancy is contraindicated as hormonal contraceptives are no. 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.