Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
OVULEN vs ALYACEN 7/7/7
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Ovulen is a combination oral contraceptive containing ethynodiol diacetate (a progestin) and mestranol (an estrogen). It inhibits ovulation by suppressing gonadotropin-releasing hormone (Gn RH) from the hypothalamus, reducing luteinizing hormone (LH) and follicle-stimulating hormone (FSH) secretion from the pituitary. It also increases cervical mucus viscosity and alters endometrial development, impeding sperm penetration and implantation.
Combination of norethindrone (progestin) and ethinyl estradiol (estrogen) that inhibits gonadotropin release from the pituitary, suppressing ovulation, increasing cervical mucus viscosity, and altering endometrial receptivity.
Prevention of pregnancy (FDA-approved indication)
Prevention of pregnancy
1 tablet (1 mg ethynodiol diacetate, 50 mcg mestranol) orally once daily for 21 days, followed by 7 days of placebo or no medication.
ALYACEN 7/7/7 is a combination oral contraceptive containing ethinyl estradiol 0.02 mg and drospirenone 3 mg. One tablet taken orally once daily for 28 days (7 active, 7 placebo, 7 active) without a hormone-free interval.
Ethinylestradiol: 10-20 hours (mean 17 hours); Dimethisterone: 10-15 hours. Clinical context: Steady state achieved after 3-5 days; elimination prolonged in hepatic impairment.
Terminal elimination half-life is 14 hours (range 12-16 h) in healthy adults; prolonged to 24-30 h in moderate renal impairment (Cr Cl 30-50 m L/min).
Ethynodiol diacetate is rapidly metabolized to norethindrone, primarily via hydrolysis, then undergoes reduction, hydroxylation, and conjugation. Mestranol is metabolized to ethinyl estradiol via demethylation, followed by further hydroxylation and conjugation. Both are metabolized by cytochrome P450 enzymes, including CYP3A4.
Norethindrone: primarily hepatic via reduction and conjugation, with CYP3A4 involvement. Ethinyl estradiol: primarily via CYP3A4, also undergoes sulfation and glucuronidation.
Renal: 50-60% as metabolites (glucuronide and sulfate conjugates), biliary/fecal: 40-50% (enterohepatic circulation).
Renal: ~50% (unchanged drug); Fecal: ~20% (via bile); Biliary: ~30% (metabolites). Total clearance is 12 L/h.
Ethinylestradiol: 97-98% bound to albumin and sex hormone-binding globulin (SHBG); Dimethisterone: ~90% bound to albumin and SHBG.
98% bound primarily to albumin; minor binding to alpha-1-acid glycoprotein.
Ethinylestradiol: 2-4 L/kg (large Vd indicating extensive tissue distribution, including reproductive tissues and fat); Dimethisterone: 1.5-2.5 L/kg.
0.35 L/kg (total body water distribution); in obesity, Vd increases to 0.5 L/kg due to lipophilicity.
Oral: Ethinylestradiol 40-60% (first-pass metabolism); Dimethisterone ~70% (oral bioavailability).
Oral: 85% (with high-fat meal reduces to 70%); Sublingual: 90%.
No specific dose adjustment guidelines available; use caution in severe renal impairment (Cr Cl <30 m L/min) due to potential hormonal accumulation.
Contraindicated in patients with severe renal impairment (Cr Cl <30 m L/min) or acute renal failure due to drospirenone's antimineralocorticoid activity. No dose adjustment recommended for mild to moderate impairment (Cr Cl ≥30 m L/min).
Contraindicated in severe hepatic impairment (Child-Pugh class C). In mild to moderate impairment (Child-Pugh A or B), use with caution; no specific dose reduction established.
Contraindicated in patients with acute hepatic disease, hepatic tumors, or impaired liver function (Child-Pugh class B or C). Discontinue if jaundice or pruritus develops. No dose adjustment for Child-Pugh class A.
Approved only for postmenarchal adolescents; same dosing as adults (1 tablet daily for 21 days with 7-day break). Not indicated before menarche.
Not indicated for use in pediatric patients before menarche. Safety and efficacy in postmenarchal adolescents are expected to be similar to adults; dose is same as adults.
Not indicated for use in postmenopausal women. Efficacy and safety in elderly (age >65 years) have not been established.
Not indicated for use in postmenopausal women. No recommendations for geriatric population due to lack of indication.
Cigarette smoking increases the risk of serious cardiovascular events from combination oral contraceptive use. The risk increases with age, especially in women over 35 years, and with the number of cigarettes smoked. Women who use combination oral contraceptives should be strongly advised not to smoke.
Cigarette smoking increases risk of serious cardiovascular events from combined oral contraceptives (COCs). Risk increases with age and amount smoked (especially >15 cigarettes/day). Women over 35 who smoke should not use COCs.
Cigarette smoking increases risk of cardiovascular events; avoid in women over 35 who smoke.,Increased risk of thromboembolic disorders (e.g., deep vein thrombosis, pulmonary embolism, stroke, myocardial infarction). Discontinue if thrombotic events occur or are suspected.,Elevated blood pressure; monitor regularly.,Gallbladder disease; may worsen or precipitate.,Hepatic neoplasia; rare cases of benign and malignant liver tumors reported.,Carcinoma of breast and reproductive organs; increased risk with long-term use; monitor if history.,Ocular lesions; discontinue if sudden partial or complete loss of vision, proptosis, diplopia, or papilledema occurs.,Glucose intolerance; use with caution in diabetics.,Unscheduled bleeding; rule out pregnancy or other causes.,Depression; discontinue if severe or recurrent.
Thrombotic disorders (thrombophlebitis, pulmonary embolism, cerebral hemorrhage, myocardial infarction),Cerebrovascular disease,Carcinoma of the breast or reproductive organs,Hepatic adenoma or carcinoma,Ocular lesions (retinal thrombosis, papilledema),Gallbladder disease,Carbohydrate/lipid effects,Elevated blood pressure,Hereditary angioedema,Chloasma,Hepatic impairment
Thrombophlebitis or thromboembolic disorders (current or history).,Cerebrovascular or coronary artery disease (current or history).,Known or suspected breast carcinoma.,Estrogen-dependent neoplasia (known or suspected).,Undiagnosed abnormal genital bleeding.,Pregnancy (known or suspected).,Benign or malignant liver tumor (current or history).,Jaundice or liver disease (acute or chronic) with abnormal liver function, unless improving.,Hypersensitivity to any component.
Breast cancer (current or history),Undiagnosed abnormal genital bleeding,Known or suspected pregnancy,Current or history of thrombotic disorders (DVT, PE, stroke, MI),Cerebrovascular or coronary artery disease,Valvular heart disease with complications,Severe hypertension,Diabetes with vascular disease,Headaches with focal neurological symptoms (e.g., migraine with aura),Major surgery with prolonged immobilization,Known thrombophilia (e.g., Factor V Leiden, prothrombin mutation, protein S/C deficiency),Active liver disease (tumors, hepatitis, cirrhosis),Uncontrolled hypertension,Smoking (if age >35),Hypersensitivity to any component
No significant food interactions. Grapefruit juice may alter estrogen metabolism but clinical relevance is minimal. Maintain regular diet; no restrictions.
Grapefruit and grapefruit juice may increase ethinyl estradiol levels, potentially increasing side effects. St. John's wort (herbal supplement) can reduce contraceptive efficacy. No other significant food interactions; however, maintaining a stable intake of vitamin C and folate is generally recommended.
FDA Pregnancy Category X. Contraindicated in pregnancy due to risk of fetal harm, including cardiovascular anomalies and limb defects. First trimester exposure associated with major congenital malformations; second and third trimester exposure may cause feminization of male fetuses.
ALYACEN 7/7/7 contains ethinylestradiol and norethindrone. First trimester: No increased risk of major birth defects based on epidemiologic studies; however, inadvertent use does not warrant termination. Second and third trimesters: Avoid use due to potential adverse effects on fetal development, including feminization of male fetuses and potential for congenital anomalies from progestin. Postnatal: Possible long-term effects on reproductive development.
Excreted in human milk; M/P ratio not established. May reduce milk production and affect infant hormonal development. Contraindicated during breastfeeding.
Contraindicated in breastfeeding. Ethinylestradiol reduces milk quantity and quality. Norethindrone is excreted in low amounts (M/P ratio approximately 0.3-0.4). However, combination oral contraceptives are not recommended during lactation due to estrogen effects on milk production.
Not applicable; contraindicated in pregnancy. No dose adjustments recommended as medication should be discontinued immediately if pregnancy occurs.
ALYACEN 7/7/7 is contraindicated in pregnancy; no dose adjustments are applicable as use is not recommended. Pharmacokinetic changes in pregnancy (increased clearance of steroids) would theoretically require higher doses, but due to fetal risks, alternative therapies should be used.
Ovulen (ethynodiol diacetate 1 mg + mestranol 0.1 mg) is a first-generation combined oral contraceptive. Monitor for thromboembolic events, especially in smokers over 35. Use with caution in patients with hypertension, migraine with aura, or liver disease. Breakthrough bleeding is common in the first 3 cycles.
ALYACEN 7/7/7 is a triphasic oral contraceptive containing ethinyl estradiol and norgestimate. The 7/7/7 regimen refers to the varying doses of norgestimate across three 7-day phases (0.18 mg, 0.215 mg, 0.25 mg) with a fixed 0.025 mg ethinyl estradiol. Use consistent 7-day placebo interval. Consider increased risk of venous thromboembolism (VTE) in patients with BMI >30, smoking >15 cigarettes/day, or age >35. Monitor for breakthrough bleeding, especially during the first 3 cycles. Avoid in patients with migraine with aura, uncontrolled hypertension, or history of DVT/PE. Drug interactions with CYP3A4 inducers (e.g., rifampin, carbamazepine) may reduce efficacy; consider backup contraception.
Take one pill daily at the same time, even if no sexual activity.,Use backup contraception (e.g., condoms) for the first 7 days of starting the pill.,Report sudden severe headache, chest pain, leg swelling, or vision changes immediately.,Smoking increases risk of serious cardiovascular side effects; avoid smoking.,Missed pills increase pregnancy risk; follow missed pill instructions in the patient leaflet.
Take one pill daily at the same time each day, in the order specified on the pack (active pills followed by placebo).,If you miss a pill, follow the package instructions; missing pills increases pregnancy risk, especially if placebo week is extended.,Common side effects include nausea, headache, breast tenderness, and spotting, which usually improve after 2-3 cycles.,Seek immediate medical attention for severe abdominal pain, chest pain, shortness of breath, leg pain/swelling, or severe headache.,This medication does not protect against HIV/AIDS or other sexually transmitted infections (STIs).,Inform your healthcare provider if you smoke, as smoking increases risk of serious cardiovascular side effects, especially if over 35 years.
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 OVULEN vs ALYACEN 7/7/7, answered by our medical review team.
OVULEN is a Oral Contraceptive that works by Ovulen is a combination oral contraceptive containing ethynodiol diacetate (a progestin) and mestranol (an estrogen). It inhibits ovulation by suppressing gonadotropin-releasing hormone (Gn RH) from the hypothalamus, reducing luteinizing hormone (LH) and follicle-stimulating hormone (FSH) secretion from the pituitary. It also increases cervical mucus viscosity and alters endometrial development, impeding sperm penetration and implantation.. ALYACEN 7/7/7 is a Oral Contraceptive that works by Combination of norethindrone (progestin) and ethinyl estradiol (estrogen) that inhibits gonadotropin release from the pituitary, suppressing ovulation, increasing cervical mucus viscosity, and altering endometrial receptivity.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between OVULEN and ALYACEN 7/7/7 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 OVULEN is: 1 tablet (1 mg ethynodiol diacetate, 50 mcg mestranol) orally once daily for 21 days, followed by 7 days of placebo or no medication.. The standard adult dose of ALYACEN 7/7/7 is: ALYACEN 7/7/7 is a combination oral contraceptive containing ethinyl estradiol 0.02 mg and drospirenone 3 mg. One tablet taken orally once daily for 28 days (7 active, 7 placebo, 7 active) without a hormone-free interval.. 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 OVULEN and ALYACEN 7/7/7 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. OVULEN is classified as Category C. FDA Pregnancy Category X. Contraindicated in pregnancy due to risk of fetal harm, including cardiovascular anomalies and limb defects. First trimester exposure associated with majo. ALYACEN 7/7/7 is classified as Category C. ALYACEN 7/7/7 contains ethinylestradiol and norethindrone. First trimester: No increased risk of major birth defects based on epidemiologic studies; however, inadvertent use does n. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.