Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
LO/OVRAL 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 estrogen-progestin oral contraceptive; suppresses gonadotropin release, primarily FSH and LH, inhibiting ovulation; increases viscosity of cervical mucus, impeding sperm penetration; alters endometrial receptivity.
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,Dysfunctional uterine bleeding,Hormonal contraception
Prevention of pregnancy,Treatment of moderate acne vulgaris (off-label use)
One tablet (30 mcg ethinyl estradiol, 0.3 mg norgestrel) orally once daily for 28-day cycle (21 active, 7 placebo).
1 tablet (ethinyl estradiol 50 mcg, norethindrone 1 mg) orally once daily for 21 days, followed by 7 days off.
Norgestrel (levonorgestrel): 11-45 hours (mean ~24 hours); ethinyl estradiol: 7-21 hours (mean ~14 hours). Half-life increases slightly with repeated dosing due to saturable metabolism.
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 is primarily metabolized by CYP3A4; norgestrel is metabolized via reduction and conjugation; both undergo first-pass metabolism.
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.
Urine (50-60% as conjugated metabolites), feces (30-40% as metabolites), enterohepatic recirculation present.
Renal (approx. 50% as metabolites, <1% unchanged), fecal (approx. 40%, largely as ethinylestradiol conjugates), biliary (minor, enterohepatic recirculation of ethinylestradiol)
Levonorgestrel: 97-99% (primarily to sex hormone-binding globulin, SHBG, and albumin); ethinyl estradiol: 97-98% (primarily to albumin, increases SHBG levels).
Ethinylestradiol: 97-98% bound to serum albumin (primarily) and SHBG; ethynodiol diacetate: >95% bound to albumin and SHBG.
Levonorgestrel: 1.0-1.3 L/kg; ethinyl estradiol: 2.3-3.0 L/kg. Reflects extensive tissue distribution and binding.
Ethinylestradiol: 2.8-4.3 L/kg (extensive tissue distribution, including breast and reproductive tissues); ethynodiol: 1.5-2.0 L/kg.
Oral: levonorgestrel ~100% (first-pass metabolism <10%), ethinyl estradiol 38-48% due to first-pass conjugation in gut wall and liver.
Oral: Ethinylestradiol 38-48% (first-pass metabolism); ethynodiol diacetate ~60% (rapid hydrolysis to active norethindrone).
No dosage adjustment required for mild to moderate impairment. Not recommended in severe renal impairment (e GFR <30 m L/min/1.73m²) due to limited data.
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 Child-Pugh class B or C (active liver disease, jaundice, or impaired synthetic function). Use discontinued if hepatic function deteriorates.
Contraindicated in acute or chronic hepatic dysfunction, including Child-Pugh class A, B, or C. Use in mild hepatic impairment not recommended.
Post-menarche adolescents: Same dosing as adults (30 mcg ethinyl estradiol/0.3 mg norgestrel daily). Not indicated pre-menarche.
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 postmenopausal women. Higher risk of thromboembolism and cardiovascular events in women >40 years, especially if smoking or other risk factors.
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 oral contraceptive use; risk increases with age (especially in women over 35 years) and with heavy smoking (≥15 cigarettes/day); 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.
Increased risk of thromboembolic disorders (e.g., MI, stroke, VTE); hepatic adenoma; risk of breast cancer; hypertension; gallbladder disease; impaired glucose tolerance; cholestatic jaundice; ocular lesions (e.g., retinal thrombosis); use in pregnancy; fluid retention; 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
Thrombophlebitis or thromboembolic disorders; cerebrovascular or coronary artery disease; known or suspected breast carcinoma; estrogen-dependent neoplasia; undiagnosed abnormal genital bleeding; known or suspected pregnancy; hepatic adenoma or malignancy; cholestatic jaundice of pregnancy or jaundice with prior pill use; active liver disease; hypersensitivity to any component; cigarette smoking in women ≥35 years; uncontrolled hypertension; diabetes with vascular involvement; headaches with focal neurological symptoms; major surgery with prolonged immobilization.
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
No significant food interactions. Grapefruit juice may increase ethinyl estradiol levels via CYP3A4 inhibition, but clinical relevance is minimal with low-dose pills. Avoid using St. John's wort, which may decrease contraceptive 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.
First trimester: No increased risk of major malformations based on epidemiological studies. Second/third trimesters: Exposure may increase risk of fetal liver tumors (rare) and possibly cardiovascular malformations; contraindicated due to feminization of male fetus. Post-market reports: Possible association with neonatal jaundice, cholestasis, and transient hormonal effects.
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.
Contraindicated during breastfeeding due to potential adverse effects on milk production and infant hormonal balance. M/P ratio not established; ethinyl estradiol and norgestrel are excreted into human milk in small amounts but insufficient data on infant exposure.
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 during pregnancy; drug is contraindicated after confirmed pregnancy. Pregnancy-induced changes in pharmacokinetics (increased clearance, volume of distribution) may reduce efficacy, but use is not recommended.
Not applicable as use is contraindicated during pregnancy. No pharmacokinetic studies have been conducted to recommend dose adjustments.
Lo/Ovral is a low-dose combined oral contraceptive containing ethinyl estradiol and norgestrel. Not recommended for use in women with BMI > 35 kg/m² due to increased thromboembolic risk. Advise consistent daily timing within a 3-hour window to maintain efficacy. Missed pill management: if one pill is missed >12 hours late, take missed pill and continue with next pill at normal time; if two or more pills are missed, take the most recent missed pill and use backup contraception for 7 days. Consider CYP3A4 inducers (e.g., rifampin, St. John's wort) that may reduce efficacy.
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 tablet daily at the same time every day.,Do not skip pills; if you miss a pill, follow the missed pill instructions in the package insert.,Use backup contraception (e.g., condoms) if you vomit or have severe diarrhea within 4 hours of taking a pill.,Avoid smoking, especially if over 35 years old, as it increases risk of serious cardiovascular side effects.,Tell your healthcare provider about all medications and supplements you take, as some may interfere with birth control effectiveness.,Lo/Ovral does not protect against HIV or other sexually transmitted infections.,Store at room temperature away from moisture and heat.
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 LO/OVRAL vs DEMULEN 1/50-21, answered by our medical review team.
LO/OVRAL is a Combination Oral Contraceptive that works by Combination estrogen-progestin oral contraceptive; suppresses gonadotropin release, primarily FSH and LH, inhibiting ovulation; increases viscosity of cervical mucus, impeding sperm penetration; alters endometrial receptivity.. 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 LO/OVRAL 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 LO/OVRAL is: One tablet (30 mcg ethinyl estradiol, 0.3 mg norgestrel) orally once daily for 28-day cycle (21 active, 7 placebo).. 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 LO/OVRAL 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. LO/OVRAL is classified as Category C. First trimester: No increased risk of major malformations based on epidemiological studies. Second/third trimesters: Exposure may increase risk of fetal liver tumors (rare) and pos. 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.