Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
MODICON 28 vs DEMULEN 1/50-21
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Combination hormonal contraceptive: ethinyl estradiol suppresses gonadotropin release, inhibiting ovulation; norethindrone induces changes in cervical mucus and endometrium, impeding sperm penetration and implantation.
DEMULEN 1/50-21 is a combined oral contraceptive containing ethinyl estradiol and ethynodiol diacetate. Ethinyl estradiol and progestins inhibit gonadotropin release (FSH and LH) from the pituitary, suppressing ovulation. Progestins also increase cervical mucus viscosity and alter endometrial receptivity, impeding sperm penetration and implantation.
Prevention of pregnancy
Prevention of pregnancy,Treatment of moderate acne vulgaris (off-label use)
One tablet orally once daily, each tablet containing 0.035 mg ethinyl estradiol and 0.4 mg norethindrone, taken at the same time each day for 21 days followed by 7 days of placebo tablets.
1 tablet (ethinyl estradiol 50 mcg, norethindrone 1 mg) orally once daily for 21 days, followed by 7 days off.
Terminal elimination half-life: 13-19 hours (mean 16 hours) for norethindrone; steady state achieved within 5-7 days.
Ethinylestradiol: 13 ± 3 h (biphasic; terminal phase used for dosing interval). Clinical context: steady-state achieved after ~3 days; missed dose may reduce contraceptive efficacy if >36 h.
Ethinyl estradiol undergoes hepatic metabolism via CYP3A4; norethindrone is metabolized primarily via reduction and conjugation, with involvement of CYP3A4.
Ethinyl estradiol undergoes first-pass metabolism in the gut wall and liver, with hydroxylation by CYP3A4 and conjugation via glucuronidation and sulfation. Ethynodiol diacetate is rapidly deacetylated to norethindrone, which is metabolized by reduction and conjugation, with CYP3A4 as a minor pathway.
Renal: 50-60% as metabolites, fecal: 40-50% as metabolites, with enterohepatic circulation; less than 1% unchanged in urine.
Renal (approx. 50% as metabolites, <1% unchanged), fecal (approx. 40%, largely as ethinylestradiol conjugates), biliary (minor, enterohepatic recirculation of ethinylestradiol)
Norethindrone: 61-67% bound to SHBG and albumin (55% to SHBG, 45% to albumin); ethinyl estradiol: 97-98% bound to albumin, not bound to SHBG.
Ethinylestradiol: 97-98% bound to serum albumin (primarily) and SHBG; ethynodiol diacetate: >95% bound to albumin and SHBG.
Norethindrone: Vd approximately 4 L/kg (range 2-6 L/kg), indicating extensive tissue distribution; ethinyl estradiol: Vd approximately 2-4 L/kg.
Ethinylestradiol: 2.8-4.3 L/kg (extensive tissue distribution, including breast and reproductive tissues); ethynodiol: 1.5-2.0 L/kg.
Oral norethindrone: 45-65% due to first-pass metabolism; ethinyl estradiol: 38-48% oral bioavailability.
Oral: Ethinylestradiol 38-48% (first-pass metabolism); ethynodiol diacetate ~60% (rapid hydrolysis to active norethindrone).
No dose adjustment required for mild to moderate renal impairment. Insufficient data for severe renal impairment (Cr Cl <30 m L/min); consider alternative contraception due to potential hormonal accumulation.
No dose adjustment required for mild-moderate renal impairment. Avoid use in severe renal impairment or dialysis due to potential fluid retention and electrolyte disturbances.
Contraindicated in acute hepatic disease or severe hepatic impairment (Child-Pugh class C). Use with caution in mild to moderate impairment (Child-Pugh A or B); monitor liver function; consider alternative contraception.
Contraindicated in acute or chronic hepatic dysfunction, including Child-Pugh class A, B, or C. Use in mild hepatic impairment not recommended.
Not indicated for use before menarche. For post-menarche adolescents: same dosing as adults (one tablet daily). Safety and efficacy established in females of reproductive age.
Not indicated for use before menarche. For post-menarcheal adolescents, same dosing as adults. Safety and efficacy established in post-pubertal females.
Not indicated for use in postmenopausal women. Efficacy for contraception not applicable; no dosing recommendations for this population.
Not indicated after menopause. Risk of thromboembolic events outweighs benefits in women over 35 who smoke or have cardiovascular risk factors.
Cigarette smoking increases risk of serious cardiovascular events from combination oral contraceptives. Risk increases with age and smoking intensity, especially in women over 35. Women should be strongly advised not to smoke.
Cigarette smoking increases the risk of serious cardiovascular events from oral contraceptive use. This risk increases with age and with the number of cigarettes smoked, and is quite marked in women over 35 years of age. Women who use oral contraceptives should be strongly advised not to smoke.
Thrombotic disorders (thrombophlebitis, venous thromboembolism, cerebrovascular disease, myocardial infarction),Hepatic disease (jaundice, hepatic adenomas),Hypertension,Gallbladder disease,Carbohydrate and lipid effects,Ocular lesions (e.g., retinal thrombosis),Headache (including migraine),Menstrual irregularities/breakthrough bleeding,Depression,Reduced efficacy with enzyme-inducing drugs,Bone mineral density changes,Hereditary angioedema
Increased risk of thrombotic disorders (venous thromboembolism, stroke, myocardial infarction),Cigarette smoking increases cardiovascular risk, especially in women over 35,Increased risk of hypertension, gallbladder disease, and hepatic neoplasia,Risk of retinal thrombosis; discontinue if unexplained vision loss occurs,May cause fluid retention; use with caution in conditions affected by fluid retention,May induce cholestatic jaundice; discontinue if jaundice develops,May cause carbohydrate and lipid metabolism changes
Known or suspected pregnancy,Current or past history of thrombophlebitis or thromboembolic disorders,Cerebrovascular disease,Coronary artery disease,Known or suspected carcinoma of the breast,Carcinoma of the endometrium or other estrogen-dependent neoplasia,Undiagnosed abnormal genital bleeding,Cholestatic jaundice of pregnancy or jaundice with prior oral contraceptive use,Hepatic adenomas or carcinomas,Known or suspected liver disease,Heavy smoking (≥15 cigarettes/day) and age ≥35,Hypersensitivity to any component
Known or suspected pregnancy,Current or past history of thrombophlebitis or thromboembolic disorders,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 oral contraceptive use,Hepatic adenoma or carcinoma,Active liver disease (e.g., acute viral hepatitis, decompensated cirrhosis),Hypersensitivity to any component
Grapefruit and grapefruit juice may increase ethinyl estradiol levels by inhibiting CYP3A4, but the effect is variable; advise caution or avoid concurrent intake. No other significant food interactions are known. High-fat meals may delay absorption but do not reduce overall efficacy.
No specific food interactions. Oral contraceptives may increase caffeine levels; limit caffeine intake if side effects like jitteriness occur. Grapefruit and grapefruit juice do not significantly affect this medication.
FDA Pregnancy Category X. First trimester: increased risk of neural tube defects, congenital heart defects, and other malformations due to estrogen/progestin exposure. Second and third trimesters: associated with elevated risks of preterm birth, low birth weight, and neonatal complications. Use contraindicated in pregnancy.
First trimester: Use contraindicated due to increased risk of congenital anomalies, particularly cardiovascular defects and limb reduction defects, associated with sex hormones. Second and third trimesters: Avoid due to risk of fetal harm, including masculinization of female fetus with progestins; also associated with increased risk of neonatal jaundice and liver dysfunction.
Safety: Small amounts of ethinyl estradiol and progestin (norethindrone) are excreted in breast milk. M/P ratio: Not established for this specific combination; ethinyl estradiol M/P ~0.2-0.4. May reduce milk production and alter milk composition. Not recommended during breastfeeding; alternative contraception advised.
Small amounts of ethinyl estradiol and ethynodiol diacetate are excreted in breast milk. M/P ratio not established. Estrogen-progestin combinations may reduce milk production and alter milk composition; use during breastfeeding is generally not recommended. Consider alternative contraception.
No dose adjustment required as drug is contraindicated in pregnancy. Pharmacokinetic changes during pregnancy (increased hepatic metabolism, volume of distribution) are not relevant due to contraindication. If inadvertent exposure occurs, discontinue drug.
Not applicable as use is contraindicated during pregnancy. No pharmacokinetic studies have been conducted to recommend dose adjustments.
MODICON 28 is a combined oral contraceptive containing ethinyl estradiol 0.035 mg and norethindrone 0.5 mg. It is crucial to counsel patients on the importance of taking the pill at the same time daily to maintain consistent hormone levels. The regimen includes 21 active pills followed by 7 placebo pills; during the placebo week, withdrawal bleeding typically occurs. For missed pills: if one pill is missed, take it as soon as remembered and continue schedule; if two or more are missed, take the most recent missed pill and use backup contraception for 7 days. Consider potential drug interactions with antibiotics, anticonvulsants (e.g., carbamazepine, phenytoin), and St. John's wort, which may reduce contraceptive efficacy. Smoking increases risk of serious cardiovascular events, especially in women over 35. Monitor blood pressure at baseline and periodically. Caution in patients with history of thromboembolic disorders, migraine with aura, hypertension, or liver disease.
DEMULEN 1/50-21 is a monophasic oral contraceptive containing ethinyl estradiol 50 mcg and ethynodiol diacetate 1 mg. Use with caution in patients over 35 who smoke due to increased cardiovascular risk. Monitor for breakthrough bleeding, especially in the first three cycles. Consider drug interactions with rifampin, anticonvulsants, and broad-spectrum antibiotics. Administer at the same time daily to maintain efficacy. The 21-day regimen requires a 7-day pill-free interval. Instruct to start on first day of menses or first Sunday after onset.
Take one pill daily at the same time, preferably after an evening meal or at bedtime to minimize nausea.,The pack contains 21 active (hormone) pills and 7 placebo (reminder) pills; withdrawal bleeding usually occurs during the placebo week.,If you miss a pill, refer to the package insert instructions; use backup contraception (e.g., condoms) if needed.,Use additional non-hormonal contraception during the first 7 days of starting the pill if switching from another method.,Seek immediate medical attention if you experience symptoms of a blood clot, such as sudden leg pain or swelling, chest pain, shortness of breath, or severe headache.,This medication does not protect against sexually transmitted infections (STIs); use condoms for STI prevention.,Inform your healthcare provider of all medications and supplements you take, especially antibiotics, anticonvulsants, and St. John's wort.,Avoid smoking, especially if over 35, as it increases the risk of serious side effects.
Take one tablet daily at the same time, starting on the first day of your menstrual period or the first Sunday after your period begins.,Swallow tablet whole with water, with or without food.,After finishing all 21 tablets, wait 7 days before starting a new pack. You will have a withdrawal bleed during this time.,If you miss a tablet by less than 12 hours, take it immediately. If more than 12 hours, take the missed tablet and use backup contraception for 7 days.,Seek emergency medical care for symptoms of blood clots (sudden severe headache, chest pain, shortness of breath, leg pain/swelling), stroke (sudden numbness/weakness, slurred speech), or liver problems (yellowing skin/eyes, dark urine).,Avoid smoking while taking this medication, especially if over age 35, due to increased risk of cardiovascular events.,Inform your healthcare provider about all other medications (including over-the-counter drugs, herbal supplements like St. John's Wort) as they may reduce contraceptive efficacy.,This medication does not protect against HIV or other sexually transmitted infections.
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 MODICON 28 vs DEMULEN 1/50-21, answered by our medical review team.
MODICON 28 is a Combination Oral Contraceptive that works by Combination hormonal contraceptive: ethinyl estradiol suppresses gonadotropin release, inhibiting ovulation; norethindrone induces changes in cervical mucus and endometrium, impeding sperm penetration and implantation.. DEMULEN 1/50-21 is a Combination Oral Contraceptive that works by DEMULEN 1/50-21 is a combined oral contraceptive containing ethinyl estradiol and ethynodiol diacetate. Ethinyl estradiol and progestins inhibit gonadotropin release (FSH and LH) from the pituitary, suppressing ovulation. Progestins also increase cervical mucus viscosity and alter endometrial receptivity, impeding sperm penetration and implantation.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between MODICON 28 and DEMULEN 1/50-21 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 MODICON 28 is: One tablet orally once daily, each tablet containing 0.035 mg ethinyl estradiol and 0.4 mg norethindrone, taken at the same time each day for 21 days followed by 7 days of placebo tablets.. The standard adult dose of DEMULEN 1/50-21 is: 1 tablet (ethinyl estradiol 50 mcg, norethindrone 1 mg) orally once daily for 21 days, followed by 7 days off.. 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 MODICON 28 and DEMULEN 1/50-21 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. MODICON 28 is classified as Category C. FDA Pregnancy Category X. First trimester: increased risk of neural tube defects, congenital heart defects, and other malformations due to estrogen/progestin exposure. Second and t. DEMULEN 1/50-21 is classified as Category C. First trimester: Use contraindicated due to increased risk of congenital anomalies, particularly cardiovascular defects and limb reduction defects, associated with sex hormones. Se. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.