Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
MODEYSO vs DEMULEN 1/35-28
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 estrogen-progestin contraceptive; suppresses gonadotropin release, inhibiting ovulation; increases cervical mucus viscosity, impeding sperm penetration; alters endometrial receptivity.
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.
Prevention of pregnancy
400 mg orally once daily with food
One tablet (contains 1 mg ethynodiol diacetate and 35 mcg ethinyl estradiol) orally once daily at the same time each day for 21 days, followed by 7 days of placebo or no tablets.
Terminal half-life approximately 6 days (range 4–10 days) in healthy subjects; supports weekly dosing interval
Ethinyl estradiol: 17.4 ± 5.6 h (terminal); norethindrone: 10.9 ± 1.6 h (terminal); clinically, steady-state achieved within 5-7 days.
Elacestrant is metabolized primarily by CYP3A4 and CYP2C8.
Ethinylestradiol undergoes hepatic metabolism via CYP3A4; norethindrone undergoes reduction and conjugation in the liver.
Renal excretion unchanged: <1%; biliary/fecal elimination: >99% as unchanged drug
Renal 50% (metabolites), fecal 50% (biliary elimination of conjugates).
Negligible (<2%) binding to plasma proteins
Ethinyl estradiol: 97-98% bound to albumin; norethindrone: 93% bound to albumin and SHBG.
Vd approximately 0.15 L/kg, consistent with distribution primarily in blood volume
Ethinyl estradiol: 2.3-4.3 L/kg; norethindrone: 4.4 L/kg; indicates extensive tissue distribution.
Intravenous only; bioavailability 100%
Ethinyl estradiol: 40-45% (oral; first-pass metabolism); norethindrone: 64-67% (oral).
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 dose adjustment required for mild to moderate renal impairment. Contraindicated in severe renal impairment or acute renal failure.
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 acute or chronic hepatic dysfunction, including Child-Pugh class A, B, or C. Avoid use if liver function tests are abnormal.
Safety and efficacy not established in pediatric patients. No recommended dosage.
Not indicated for use before menarche. For postmenarchal adolescents, use same dosing as adults (one tablet orally once daily).
No specific dosage adjustment recommended; monitor renal function due to age-related decline.
Not indicated for use in postmenopausal women.
No black box warning.
Cigarette smoking increases risk of serious cardiovascular events. Risk increases with age and smoking intensity. 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.
Increased risk of thromboembolic disorders,Cerebrovascular disease,Myocardial infarction,Hepatic neoplasia,Gallbladder disease,Hypertension,Carbohydrate/lipid effects,Headache,Uterine bleeding,Ocular lesions,Depression
None known.
Known or suspected pregnancy,Current or past thrombosis,Cerebrovascular or coronary artery disease,Valvular heart disease with complications,Severe hypertension,Diabetes with vascular involvement,Headaches with focal neurological symptoms,Major surgery with prolonged immobilization,Known or suspected breast cancer,Endometrial cancer or other estrogen-dependent neoplasia,Undiagnosed abnormal genital bleeding,Cholestatic jaundice of pregnancy or jaundice with prior pill use,Hepatic adenomas or carcinomas,Active liver disease,Known 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 has minimal effect on ethinyl estradiol; no restriction needed. Avoid excessive alcohol, which may impair adherence or increase liver enzymes. St. John's wort reduces contraceptive efficacy and should be avoided.
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.
First trimester: Increased risk of neural tube defects, cardiovascular anomalies, and oral clefts (OR ~1.3-1.6). Second/third trimester: Androgenization of female fetus (clitoromegaly, labial fusion) due to progestin component; possible association with hypospadias in males with first-trimester exposure. Avoid use in pregnancy.
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.
Excreted in breast milk; estimated infant dose <1% of maternal dose. M/P ratio not available for ethinyl estradiol/ethynodiol diacetate. May reduce milk production and quality. Use only if benefits outweigh risks; lowest effective dose recommended.
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.
Contraindicated in pregnancy; no dose adjustment applicable. If inadvertently used, discontinue immediately.
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 1/35-28 (ethinyl estradiol 35 mcg + ethynodiol diacetate 1 mg) is a monophasic combined oral contraceptive. Its progestin has mild androgenic activity, which may be less favorable for acne-prone patients compared to third-generation pills. The 28-day pack includes 21 active pills and 7 inert pills. Counsel patients to take at the same time daily; missed pills increase breakthrough bleeding and pregnancy risk. It may be used off-label for cycle control in patients without contraindications.
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 after dinner to reduce nausea.,If you miss one pill, take it as soon as remembered; if missed more than one, use backup contraception for 7 days.,Smoking increases risk of blood clots; especially dangerous if over 35 and smokes.,Some antibiotics (e.g., rifampin) and antiseizure medications may reduce effectiveness.,Report any signs of blood clot: sudden leg pain/swelling, chest pain, shortness of breath, or sudden severe headache.,Breakthrough bleeding is common in first 3 cycles; if persistent, contact your healthcare provider.,Do not use if pregnant; if pregnancy occurs, stop immediately.
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 1/35-28, 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 1/35-28 is a Combination Oral Contraceptive that works by Combination estrogen-progestin contraceptive; suppresses gonadotropin release, inhibiting ovulation; increases cervical mucus viscosity, impeding sperm penetration; alters endometrial receptivity.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between MODEYSO and DEMULEN 1/35-28 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 1/35-28 is: One tablet (contains 1 mg ethynodiol diacetate and 35 mcg ethinyl estradiol) orally once daily at the same time each day for 21 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 MODEYSO and DEMULEN 1/35-28 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 1/35-28 is classified as Category C. First trimester: Increased risk of neural tube defects, cardiovascular anomalies, and oral clefts (OR ~1.3-1.6). Second/third trimester: Androgenization of female fetus (clitoromeg. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.