Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
LOW-OGESTREL-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: ethinyl estradiol and norgestrel inhibit ovulation via suppression of gonadotropins (LH, FSH); increase viscosity of cervical mucus, impairing sperm penetration; alter endometrial structure, reducing implantation likelihood.
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,Oral contraception
Prevention of pregnancy
One tablet (norgestrel 0.3 mg/ethinyl estradiol 30 mcg) orally once daily at the same time each day for 28 days, with 21 active tablets followed by 7 inactive 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.
Norgestrel: ~45 hours (terminal). Ethinyl estradiol: ~13 hours (terminal). Steady-state achieved within 5-7 days.
Norethindrone: 8-11 hours (terminal); ethinyl estradiol: 10-20 hours (terminal). The half-life supports once-daily dosing for oral contraceptive efficacy.
Ethinyl estradiol: metabolized via CYP3A4, undergoes first-pass metabolism, conjugates with sulfate and glucuronide. Norgestrel: primarily metabolized via reduction, hydroxylation, and conjugation; CYP3A4 involved.
Ethinyl estradiol: primarily hepatic via CYP3A4; norethindrone: hepatic reduction and sulfate conjugation.
Renal 50-60% as metabolites, fecal 40-50% via biliary elimination. Ethinyl estradiol undergoes enterohepatic recirculation.
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: 97-99% bound to SHBG and albumin. Ethinyl estradiol: 98% bound to albumin.
Norethindrone: 61% bound to albumin and SHBG; ethinyl estradiol: 97-98% bound to albumin.
Norgestrel: 3-4 L/kg (extensive tissue distribution). Ethinyl estradiol: 3-5 L/kg.
Norethindrone: 3.8-4.5 L/kg; ethinyl estradiol: 2.0-4.0 L/kg. Large Vd indicates extensive tissue distribution.
Norgestrel: ~90% oral (first-pass metabolism minimal). Ethinyl estradiol: ~45% oral (extensive first-pass 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 impairment (Cr Cl <30 m L/min); use with caution.
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 or liver tumors (Child-Pugh class C). For mild to moderate impairment (Child-Pugh A or B), use with caution and monitor liver function; no specific dose adjustment 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.
Not indicated for premenarchal patients. Postmenarchal adolescents: same as adult dose (one tablet daily) after menarche.
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 postmenopausal women due to lack of contraceptive need and potential increased risks of thrombosis, cardiovascular events, and malignancies.
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. Risk increases with age and heavy smoking (≥15 cigarettes/day) and is significant in women over 35. Women who use combination hormonal contraceptives should be strongly advised not to 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.
Thrombotic events (e.g., DVT, PE, stroke, MI); hepatic neoplasia; elevated blood pressure; gallbladder disease; carbohydrate and lipid metabolism effects; headache; uterine bleeding irregularities; ectopic pregnancy risk; reduced efficacy with hepatic impairment; monitoring for hypertension, hyperlipidemia, and glucose intolerance.
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; history of DVT or PE; cerebrovascular or coronary artery disease; known or suspected breast carcinoma; endometrial carcinoma 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.
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 ethinyl estradiol levels due to CYP3A4 inhibition, but clinical significance is minimal. Maintain consistent dietary habits regarding grapefruit consumption to avoid fluctuation in drug levels. Alcohol does not directly affect efficacy but may impair judgment regarding compliance.
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: Low risk of major malformations; no evidence of increased risk of neural tube defects. Second and third trimesters: Possible increased risk of liver tumors and jaundice; may cause fetal harm if administered during pregnancy due to hormonal effects. Post-marketing reports of external genitalia anomalies in male and female fetuses exposed to progestins. Not recommended for use during pregnancy. Discontinue if pregnancy occurs.
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).
Excreted in breast milk in small amounts; estimated M/P ratio approximately 0.5-0.8 for progestins. May reduce milk production and quality. Use with caution and only if clearly needed. Monitor infant for jaundice, weight gain, and hormonal effects.
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.
No dose adjustments recommended in pregnancy as drug is contraindicated. Pharmacokinetic changes in pregnancy (increased clearance, volume of distribution) may reduce efficacy if used inadvertently; discontinue immediately upon recognition of pregnancy.
Contraindicated in pregnancy; no dose adjustments applicable. Discontinue medication immediately upon pregnancy detection.
Low-Ogestrel-28 (norgestrel/ethinyl estradiol) is a monophasic oral contraceptive. Take at the same time daily to maintain hormone levels. Missed pill management: if one pill is missed, take it as soon as remembered; if two or more pills are missed, use backup contraception for 7 days. Consider potential drug interactions with CYP3A4 inducers (e.g., rifampin, certain anticonvulsants) which may reduce efficacy. Breakthrough bleeding is common in first 3 months; if persistent, rule out pregnancy or cervical pathology. Do not use in patients with history of thromboembolic disease, migraines with aura, or smokers >35 years old.
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, even if you do not have intercourse.,If you miss a pill, refer to the packaging instructions or contact your healthcare provider.,Use a backup method (e.g., condoms) during the first week and if doses are missed.,Common side effects include nausea, breast tenderness, breakthrough bleeding, and mood changes; these often improve after 3 months.,Serious risks include blood clots, stroke, and liver tumors; seek medical help for leg pain, chest pain, severe headache, or vision changes.,Do not smoke while taking this medication, especially if over 35 years old.,Inform all healthcare providers that you are taking this contraceptive.,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 LOW-OGESTREL-28 vs ALYACEN 1/35, answered by our medical review team.
LOW-OGESTREL-28 is a Oral Contraceptive that works by Combination oral contraceptive: ethinyl estradiol and norgestrel inhibit ovulation via suppression of gonadotropins (LH, FSH); increase viscosity of cervical mucus, impairing sperm penetration; alter endometrial structure, reducing implantation likelihood.. 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 LOW-OGESTREL-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 LOW-OGESTREL-28 is: One tablet (norgestrel 0.3 mg/ethinyl estradiol 30 mcg) orally once daily at the same time each day for 28 days, with 21 active tablets followed by 7 inactive 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 LOW-OGESTREL-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. LOW-OGESTREL-28 is classified as Category C. First trimester: Low risk of major malformations; no evidence of increased risk of neural tube defects. Second and third trimesters: Possible increased risk of liver tumors and jau. 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.