Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
MODEYSO vs DEMULEN 1/50-28
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
The mechanism of action of MODEYSO (elacestrant) is not fully elucidated. Elacestrant is an estrogen receptor antagonist that binds to estrogen receptor alpha (ERα) and degrades it, inhibiting estrogen-mediated signaling and tumor growth in ER-positive breast cancer.
Combination oral contraceptive: Ethinyl estradiol and ethynodiol diacetate suppress gonadotropin secretion (LH, FSH) via negative feedback, inhibiting ovulation. Ethynodiol diacetate also increases cervical mucus viscosity and induces endometrial changes.
Treatment of postmenopausal women or adult men with estrogen receptor (ER)-positive, human epidermal growth factor receptor 2 (HER2)-negative, ESR1-mutated advanced or metastatic breast cancer with disease progression following at least one line of endocrine therapy.
FDA: Prevention of pregnancy,Off-label: Treatment of acne vulgaris, dysmenorrhea, endometriosis-related pain, menstrual irregularity
400 mg orally once daily with food
One tablet orally once daily for 28 consecutive days per cycle.
Terminal half-life approximately 6 days (range 4–10 days) in healthy subjects; supports weekly dosing interval
Ethinylestradiol: terminal elimination half-life ~13-27 hours (mean ~17 hours); ethynodiol diacetate (as norethindrone): terminal elimination half-life ~8-11 hours; clinical context: achieved steady-state within 5-10 days; accumulation not significant due to dose interval.
Elacestrant is metabolized primarily by CYP3A4 and CYP2C8.
Ethinyl estradiol: CYP3A4; undergoes first-pass metabolism with sulfation and glucuronidation. Ethynodiol diacetate: Deacetylated to norethynodrel, then extensively metabolized via reduction and conjugation.
Renal excretion unchanged: <1%; biliary/fecal elimination: >99% as unchanged drug
Ethinylestradiol and ethynodiol diacetate are extensively metabolized; urinary excretion accounts for ~40% of ethinylestradiol metabolites and ~50-60% of ethynodiol diacetate metabolites; fecal excretion accounts for ~30% of ethinylestradiol metabolites and ~35% of ethynodiol diacetate metabolites; biliary excretion contributes to enterohepatic circulation.
Negligible (<2%) binding to plasma proteins
Ethinylestradiol: >97% bound, primarily to albumin, with ~2% bound to sex hormone-binding globulin (SHBG); ethynodiol diacetate (as norethindrone): ~95% bound, primarily to albumin and SHBG.
Vd approximately 0.15 L/kg, consistent with distribution primarily in blood volume
Ethinylestradiol: Vd ~2-4 L/kg; distributes extensively into body tissues; ethynodiol diacetate (as norethindrone): Vd ~4 L/kg; indicates wide distribution including reproductive tissues.
Intravenous only; bioavailability 100%
Oral: ethinylestradiol bioavailability ~40-60% due to first-pass metabolism; ethynodiol diacetate bioavailability ~60-80% after oral administration.
No dosage adjustment required for mild to moderate renal impairment (GFR ≥30 m L/min). Not recommended in severe renal impairment (GFR <30 m L/min) or end-stage renal disease.
No dosage adjustment required for renal impairment. Use is not recommended in patients with severe renal impairment due to potential adverse effects.
Mild hepatic impairment (Child-Pugh A): No adjustment. Moderate hepatic impairment (Child-Pugh B): Reduce to 200 mg once daily. Severe hepatic impairment (Child-Pugh C): Avoid use.
Contraindicated in patients with Child-Pugh C cirrhosis. For Child-Pugh A or B, use is generally not recommended; if used, monitor closely for adverse effects.
Safety and efficacy not established in pediatric patients. No recommended dosage.
Not indicated for use before menarche. For postmenarchal adolescents, same dosing as adults: one tablet orally once daily for 28 days per cycle.
No specific dosage adjustment recommended; monitor renal function due to age-related decline.
Not indicated for use in postmenopausal women. No specific dose adjustment recommended for elderly, but consider increased risk of thromboembolic disorders.
No black box warning.
Cigarette smoking increases risk of serious cardiovascular events (e.g., myocardial infarction, stroke, thromboembolism). Risk increases with age and heavy smoking (≥15 cigarettes/day). Women over 35 who smoke should not use this product.
Dysphagia and esophageal injury risk: Instruct patients to take MODEYSO with water, swallow whole, and not to crush or chew. Advise patients to report signs of esophageal injury.,Embryo-fetal toxicity: Can cause fetal harm. Advise females of reproductive potential to use effective contraception during treatment and for 1 week after the last dose.
Thromboembolic disorders (DVT, PE, stroke, MI),Hepatic neoplasia (benign/malignant liver tumors),Increased risk of gallbladder disease,Hypertension,Carbohydrate/lipid metabolic effects,Ocular disturbances (retinal thrombosis, optic neuritis),Depression,Fetal harm if used during pregnancy
None known.
Thrombophlebitis or thromboembolic disorders (current or history),Cerebrovascular or coronary artery disease,Known or suspected breast cancer,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
No specific food interactions. Grapefruit juice may increase estrogen levels due to CYP3A4 inhibition, but clinical significance is unknown. Avoid St. John's Wort as it reduces contraceptive efficacy by inducing CYP3A4.
No significant food interactions. Grapefruit juice may increase estrogen levels, but clinical significance is unclear. Maintain consistent intake of vitamin C-rich foods as they may increase estrogen absorption. Avoid St. John's wort, which reduces contraceptive efficacy.
MODEYSO (mifepristone) is contraindicated in pregnancy for elective abortion. If inadvertently used during early pregnancy, there is a risk of complete abortion. In later pregnancy, it is used as part of medical abortion regimen. No known teratogenic effects if pregnancy continues after failed abortion, but data are limited.
Contraindicated in pregnancy. First trimester: increased risk of neural tube defects, congenital heart defects, and limb reduction defects from progestins. Second and third trimesters: association with masculinization of female fetus, adrenal suppression, and possible long-term metabolic effects. Estrogen component may increase risk of VACTERL anomalies.
Mifepristone is excreted into breast milk in low amounts; relative infant dose estimated <1%. M/P ratio approximately 0.5. Consider temporary discontinuation of breastfeeding for 1-2 days after administration.
Contraindicated during breastfeeding. Estrogens reduce milk production and quality. M/P ratio not established; ethinyl estradiol and norgestrel are excreted in breast milk in small amounts, potentially causing adverse effects in the infant.
No dose adjustment needed for mifepristone in pregnancy as it is used at standard doses for medical abortion. Pharmacokinetic changes in pregnancy (increased volume of distribution) do not necessitate dose alteration due to its single-dose regimen.
No adjustments; absolute contraindication in pregnancy. Drug should be discontinued immediately upon pregnancy diagnosis. No established safe dose in pregnancy.
MODEYSO (drospirenone/estetrol) is a combined oral contraceptive containing estetrol, a fetal estrogen with unique tissue selectivity. It has a shorter half-life than ethinyl estradiol, potentially reducing thrombotic risk. Monitor potassium levels in patients with renal impairment or those on potassium-sparing diuretics due to drospirenone's antimineralocorticoid activity. Breakthrough bleeding may be more common in the first few cycles. Contraindicated in patients with liver disease, history of DVT/PE, or migraines with aura.
Demulen 1/50-28 is a monophasic combined oral contraceptive containing ethinyl estradiol 50 mcg and ethynodiol diacetate 1 mg. Due to the 50 mcg estrogen dose, it carries an increased risk of venous thromboembolism compared to lower-dose pills; avoid in patients with migraine with aura, hypertension >160/100 mm Hg, or age >35 who smoke. The 28-day pack includes 21 active pills and 7 placebo pills; breakthrough bleeding is more common with higher estrogen. Caution with hepatic enzyme inducers like rifampin or anticonvulsants may reduce efficacy.
Take one tablet daily at the same time, with or without food. Do not skip doses.,If you miss a dose, follow the patient leaflet instructions; use backup contraception if needed.,Smoking increases risk of serious cardiovascular side effects; avoid smoking especially if over 35 years old.,Report symptoms of blood clots: sudden leg pain/swelling, chest pain, shortness of breath, or sudden vision changes.,May cause irregular bleeding initially; consult your healthcare provider if bleeding is prolonged or heavy.,Do not take with other medications that increase potassium (e.g., NSAIDs, ACE inhibitors, potassium supplements) without medical advice.
Take one pill daily at the same time, preferably with food to reduce nausea.,The first 7 days of the first cycle require a backup contraceptive method if not starting on day 1 of menses.,Missed pill: if one active pill is missed, take it as soon as remembered and continue; if two or more active pills are missed, take the last missed pill, skip the others, use backup for 7 days, and consider emergency contraception.,Smoking increases risk of serious cardiovascular side effects; avoid smoking, especially if over 35.,Report symptoms of blood clots: sudden leg pain/swelling, chest pain, shortness of breath, or severe headache.,The 7 placebo pills are for withdrawal bleeding; start next pack on time regardless of bleeding.
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 MODEYSO vs DEMULEN 1/50-28, answered by our medical review team.
MODEYSO is a Combination Oral Contraceptive that works by The mechanism of action of MODEYSO (elacestrant) is not fully elucidated. Elacestrant is an estrogen receptor antagonist that binds to estrogen receptor alpha (ERα) and degrades it, inhibiting estrogen-mediated signaling and tumor growth in ER-positive breast cancer.. DEMULEN 1/50-28 is a Combination Oral Contraceptive that works by Combination oral contraceptive: Ethinyl estradiol and ethynodiol diacetate suppress gonadotropin secretion (LH, FSH) via negative feedback, inhibiting ovulation. Ethynodiol diacetate also increases cervical mucus viscosity and induces endometrial changes.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between MODEYSO and DEMULEN 1/50-28 depend on the specific clinical indication. These are both Combination 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 MODEYSO is: 400 mg orally once daily with food. The standard adult dose of DEMULEN 1/50-28 is: One tablet orally once daily for 28 consecutive days per cycle.. 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 MODEYSO and DEMULEN 1/50-28 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. MODEYSO is classified as Category C. MODEYSO (mifepristone) is contraindicated in pregnancy for elective abortion. If inadvertently used during early pregnancy, there is a risk of complete abortion. In later pregnancy. DEMULEN 1/50-28 is classified as Category C. Contraindicated in pregnancy. First trimester: increased risk of neural tube defects, congenital heart defects, and limb reduction defects from progestins. Second and third trimest. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.