Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
LO LOESTRIN FE 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
Combination of ethinyl estradiol and norethindrone acetate suppresses gonadotropin-releasing hormone (Gn RH) from the hypothalamus, reducing luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the pituitary, thereby inhibiting ovulation. The progestin component thickens cervical mucus, impeding sperm penetration, and alters endometrial receptivity. Ferrous fumarate provides supplemental iron.
Combination estrogen-progestin contraceptive; suppresses gonadotropin release, inhibiting ovulation; increases cervical mucus viscosity, impeding sperm penetration; alters endometrial receptivity.
Oral contraception,Treatment of heavy menstrual bleeding (off-label),Dysmenorrhea (off-label),Acne vulgaris (off-label),Polycystic ovary syndrome (off-label)
Prevention of pregnancy
One tablet orally once daily. Each tablet contains norethindrone acetate 1 mg and ethinyl estradiol 10 mcg (24 active tablets) followed by ferrous fumarate 75 mg (2 inactive tablets).
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.
Norethindrone: ~8 hours (range 5–12 h); Ethinyl estradiol: ~14 hours (range 10–20 h). Terminal half-life supports once-daily dosing with steady-state reached within 7–14 days.
Ethinyl estradiol: 17.4 ± 5.6 h (terminal); norethindrone: 10.9 ± 1.6 h (terminal); clinically, steady-state achieved within 5-7 days.
Ethinyl estradiol is metabolized primarily via CYP3A4, with hydroxylation and conjugation pathways. Norethindrone acetate is rapidly hydrolyzed to norethindrone, which is metabolized via reduction and conjugation. Ferrous fumarate is absorbed and utilized for hemoglobin synthesis.
Ethinylestradiol undergoes hepatic metabolism via CYP3A4; norethindrone undergoes reduction and conjugation in the liver.
Renal (primarily as glucuronide conjugates of norethindrone and ethinyl estradiol): ~40% norethindrone metabolites, ~30% ethinyl estradiol metabolites; Fecal: ~30% norethindrone metabolites, ~40% ethinyl estradiol metabolites.
Renal 50% (metabolites), fecal 50% (biliary elimination of conjugates).
Norethindrone: ~61% bound (primarily to albumin and SHBG); Ethinyl estradiol: ~97–98% bound (primarily to albumin, with ~1–2% free).
Ethinyl estradiol: 97-98% bound to albumin; norethindrone: 93% bound to albumin and SHBG.
Norethindrone: ~4 L/kg; Ethinyl estradiol: ~3–4 L/kg. Indicates extensive tissue distribution consistent with lipophilic steroids.
Ethinyl estradiol: 2.3-4.3 L/kg; norethindrone: 4.4 L/kg; indicates extensive tissue distribution.
Norethindrone: ~64% (oral); Ethinyl estradiol: ~45% (oral) due to first-pass metabolism, with high interindividual variability.
Ethinyl estradiol: 40-45% (oral; first-pass metabolism); norethindrone: 64-67% (oral).
No specific dosage adjustment required for renal impairment. Use with caution in patients with renal dysfunction due to potential fluid retention.
No dose adjustment required for mild to moderate renal impairment. Contraindicated in severe renal impairment or acute renal failure.
Contraindicated in patients with hepatic impairment, including acute or chronic liver disease, hepatic adenomas, or impaired liver function. No adjustment guidelines available; do not use.
Contraindicated in acute or chronic hepatic dysfunction, including Child-Pugh class A, B, or C. Avoid use if liver function tests are abnormal.
Not indicated for use before menarche. For post-menarchal adolescents, same dosing as adults: one tablet orally once daily.
Not indicated for use before menarche. For postmenarchal adolescents, use same dosing as adults (one tablet orally once daily).
Not indicated for use in postmenopausal women. No specific dosing adjustments for elderly patients as the drug is not used in this population.
Not indicated for use in postmenopausal women.
Cigarette smoking increases the risk of serious cardiovascular events from combination oral contraceptives. Risk increases with age and heavy smoking (≥15 cigarettes/day). Women over 35 who smoke should not use this product.
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.
Increased risk of venous thromboembolism (VTE), myocardial infarction, and stroke, especially in smokers and women with hypertension or migraines,Adverse effects on bone density and potential for fractures with long-term use,Hepatic adenoma or hepatocellular carcinoma risk,Gallbladder disease,Glucose intolerance and insulin resistance,Elevated blood pressure,Cholestatic jaundice,Ocular lesions (e.g., retinal thrombosis),Depression,Iron overload in patients with hemochromatosis or chronic hemolytic anemia (due to ferrous fumarate)
Increased risk of thromboembolic disorders,Cerebrovascular disease,Myocardial infarction,Hepatic neoplasia,Gallbladder disease,Hypertension,Carbohydrate/lipid effects,Headache,Uterine bleeding,Ocular lesions,Depression
Current or history of thrombophlebitis, DVT, or thromboembolic disorders,Cerebrovascular or coronary artery disease,Known or suspected pregnancy,Undiagnosed abnormal uterine bleeding,Breast carcinoma or other hormone-sensitive cancer,Hepatic tumor (benign or malignant) or active liver disease,Hypersensitivity to any component,Smoking in women over 35,Hemochromatosis or chronic hemolytic anemia (due to ferrous fumarate)
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 are known for Lo Loestrin Fe. However, grapefruit juice may increase ethinyl estradiol levels, potentially increasing side effects; it is prudent to advise against excessive grapefruit juice consumption. Iron tablets should be taken with food to reduce gastrointestinal upset; calcium-rich foods or supplements may decrease iron absorption, so separate iron intake from high-calcium meals by at least 2 hours.
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.
Pregnancy category X. Contraindicated in pregnant women due to risk of fetal harm, including cardiovascular defects and neural tube defects. Use during first trimester associated with oral clefts; second and third trimester use may lead to fetal hyperbilirubinemia and jaundice.
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.
Excreted in breast milk in small amounts; no reported adverse effects in infants. M/P ratio for ethinyl estradiol is approximately 0.04. Use with caution, especially during early postpartum period due to potential effects on milk production.
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.
Not applicable; drug is contraindicated in pregnancy. No dose adjustments recommended due to absence of safe therapeutic use.
Contraindicated in pregnancy; no dose adjustment applicable. If inadvertently used, discontinue immediately.
Lo Loestrin Fe contains norethindrone acetate and ethinyl estradiol (1 mg/10 mcg) as the active hormonal pills, with a low iron (75 mg ferrous fumarate) supplement during the placebo week. It is the lowest-dose combination oral contraceptive available, which may minimize estrogen-related side effects. The regimen is 24 active pills, 2 placebo pills, then 2 iron pills, for a 28-day cycle. Spotting and breakthrough bleeding are common, especially in the first few cycles. It is indicated for contraception and not for emergency contraception. The iron tablets do not replace iron deficiency treatment. Contraindicated in patients with a history of thromboembolic disorders, liver disease, or known/suspected pregnancy.
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 pill daily at the same time each day, preferably after the evening meal.,The first 24 pills are light blue (hormonal), the next 2 are white (placebo), and the last 2 are brown (iron tablets).,If you miss a dose: take it as soon as remembered, and if more than 12 hours late, use backup contraception for 7 days.,Common side effects: spotting, nausea, breast tenderness, and mood changes; these often improve after 3 months.,If you experience severe abdominal or chest pain, headache, or vision changes, seek medical attention.,Iron pills do not treat anemia; they only supplement daily iron needs.,Report any jaundice, depression, or high blood pressure to your healthcare provider.,Use an additional non-hormonal method if starting for the first time after the 5th day of your period.
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 LO LOESTRIN FE vs DEMULEN 1/35-28, answered by our medical review team.
LO LOESTRIN FE is a Combination Oral Contraceptive that works by Combination of ethinyl estradiol and norethindrone acetate suppresses gonadotropin-releasing hormone (Gn RH) from the hypothalamus, reducing luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the pituitary, thereby inhibiting ovulation. The progestin component thickens cervical mucus, impeding sperm penetration, and alters endometrial receptivity. Ferrous fumarate provides supplemental iron.. 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 LO LOESTRIN FE 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 LO LOESTRIN FE is: One tablet orally once daily. Each tablet contains norethindrone acetate 1 mg and ethinyl estradiol 10 mcg (24 active tablets) followed by ferrous fumarate 75 mg (2 inactive tablets).. 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 LO LOESTRIN FE 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. LO LOESTRIN FE is classified as Category C. Pregnancy category X. Contraindicated in pregnant women due to risk of fetal harm, including cardiovascular defects and neural tube defects. Use during first trimester associated w. 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.