Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
NORDETTE-28 vs ESTROSTEP FE
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Combined estrogen-progestin oral contraceptive. Suppresses gonadotropin (FSH, LH) release from pituitary, inhibiting ovulation. Increases cervical mucus viscosity and alters endometrial lining.
Combination estrogen-progestin contraceptive: ethinyl estradiol suppresses gonadotropin release via negative feedback on hypothalamic-pituitary axis; norethindrone acetate produces progestational effects including endometrial transformation and cervical mucus thickening, inhibiting sperm penetration and implantation.
Prevention of pregnancy
Prevention of pregnancy,Treatment of moderate acne vulgaris (in females ≥15 years with no known contraindications, who have achieved menarche)
One tablet orally once daily for 28 consecutive days.
One tablet daily orally, each tablet contains norethindrone acetate 1 mg and ethinyl estradiol 20 mcg (24 active tablets) followed by ferrous fumarate 75 mg tablets (4 placebo tablets).
Ethinyl estradiol: 13-27 hours (mean 17 hours); Levonorgestrel: 11-45 hours (mean 24 hours); clinical context: steady-state reached after 5-7 days.
Ethinyl estradiol: 13-27 hours (terminal); norethindrone acetate: 5-14 hours. Clinical context: Steady-state reached within 7-10 days.
Ethinylestradiol is metabolized primarily via CYP3A4; levonorgestrel is metabolized via CYP3A4 and to a lesser extent CYP2C19 and CYP2C9.
Ethinyl estradiol: primarily metabolized by CYP3A4; undergoes sulfation and glucuronidation. Norethindrone acetate: hydrolyzed to norethindrone, then metabolized by reduction and glucuronidation.
Renal: ~50% as metabolites, ~20% unchanged; Fecal: ~30% as metabolites; Biliary: minimal.
Renal: ~40% as metabolites; fecal: ~30% (biliary); remainder as conjugates.
Ethinyl estradiol: ~97% bound to albumin; Levonorgestrel: ~98% bound to SHBG (sex hormone-binding globulin) and albumin.
Ethinyl estradiol: 97-98% bound to albumin and SHBG; norethindrone acetate: 91-95% bound to albumin and SHBG.
Ethinyl estradiol: 2.9-4.3 L/kg; Levonorgestrel: 1.8-2.1 L/kg; clinical meaning: extensive tissue distribution, not limited to plasma.
Ethinyl estradiol: 2.3-3.6 L/kg; norethindrone acetate: 1.5-2.5 L/kg. Indicates extensive tissue distribution.
Oral: Ethinyl estradiol ~45% (first-pass metabolism); Levonorgestrel ~100% (minimal first-pass).
Oral: Ethinyl estradiol ~45% (first-pass metabolism); norethindrone acetate ~64%.
No dose adjustment required for mild to moderate renal impairment. Contraindicated in severe renal impairment or acute renal failure due to potential for fluid retention and hyperkalemia.
No dose adjustment is recommended for patients with mild to moderate renal impairment. Use is contraindicated in patients with severely impaired renal function (GFR <30 m L/min/1.73 m²) due to potential for fluid retention and hyperkalemia.
Contraindicated in severe hepatic disease (Child-Pugh class C). For mild to moderate impairment (Child-Pugh A or B), use with caution and monitor liver function; no specific dose adjustment recommended.
Contraindicated in patients with acute or chronic hepatic dysfunction (Child-Pugh class B or C). For mild hepatic impairment (Child-Pugh class A), use with caution and monitor liver function; no specific dose adjustment guidelines are established.
Not indicated for use in pediatric patients before menarche. For postmenarchal adolescents, same dosing as adults: one tablet orally daily for 28 days.
Safety and efficacy have not been established in pediatric patients below 16 years of age. Post-pubertal adolescents may be dosed as adults, with careful consideration of risks (e.g., bone density).
Not indicated for use in postmenopausal women. No specific dose adjustment in elderly patients without contraindications, but consider increased risk of thromboembolism and cardiovascular events.
Not indicated for use in women over 65 years due to lack of efficacy and safety data, and increased risk of cardiovascular and thrombotic events.
Cigarette smoking increases risk of serious cardiovascular events from combined oral contraceptives. Risk increases with age (especially >35 years) and with heavy smoking (≥15 cigarettes/day). Women over 35 who smoke should not use this product.
Cigarette smoking increases risk of serious cardiovascular events from combination oral contraceptives. Risk increases with age and smoking intensity (especially >35 years). Women >35 years who smoke should not use this product.
Risk of thrombotic and thromboembolic events (venous and arterial),Risk of myocardial infarction and stroke,Increased risk of hepatic neoplasia,Elevated blood pressure,Gallbladder disease,Carbohydrate and lipid effects,Exacerbation of hereditary angioedema,Chloasma,Retinal thrombosis,Depression,Reduced efficacy with enzyme-inducing drugs,Irregular bleeding,Amenorrhea and oligomenorrhea,Lactation
Thromboembolic disorders, cardiovascular disease (MI, stroke), hypertension, gallbladder disease, hepatic neoplasia, lipid effects, glucose intolerance, headache, breakthrough bleeding, depression, contact lens intolerance, fluid retention, hereditary angioedema.
Known or suspected pregnancy,Current or past history of thrombotic disorders (e.g., DVT, PE),Cerebrovascular or coronary artery disease,Valvular heart disease with complications,Uncontrolled hypertension,Diabetes with vascular involvement,Headaches with focal neurological symptoms (e.g., migraine with aura),Major surgery with prolonged immobilization,Known or suspected breast cancer or estrogen-dependent neoplasia,Undiagnosed abnormal genital bleeding,Hepatic adenoma or carcinoma, known or suspected,Active liver disease with impaired liver function,Hypersensitivity to any component,Cigarette smoking in women over 35 years old
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 pill use, hepatic adenoma or carcinoma, pregnancy, hypersensitivity to any component.
Avoid large amounts of grapefruit or grapefruit juice as they can increase ethinyl estradiol levels. St. John's wort may reduce contraceptive efficacy. No other specific dietary restrictions. A well-balanced diet is recommended.
No specific food interactions are reported for Estrostep Fe. Grapefruit juice may slightly increase estrogen levels but is not considered clinically significant. There are no dietary restrictions. However, patients should maintain a consistent intake of folic acid if planning pregnancy; iron supplements can be taken with food to reduce GI upset.
FDA Pregnancy Category X. Estrogens and progestins are contraindicated in pregnancy due to risk of fetal harm, including cardiovascular defects and limb reduction defects. Use during first trimester is associated with congenital anomalies; second and third trimester use may cause genitourinary abnormalities and delayed fetal development.
Category X. Estrostep FE (norethindrone acetate/ethinyl estradiol/ferrous fumarate) is contraindicated in pregnancy. First trimester: increased risk of neural tube defects, cardiovascular anomalies, and limb reduction defects from sex hormones. Second/third trimester: feminization of male fetus, potential for urogenital malformations, and long-term reproductive tract effects. Postnatal: possible increased risk of childhood cancers.
Excreted in human breast milk in small amounts. M/P ratio not established. May reduce milk production and quality. Use during breastfeeding is not recommended; consider alternative contraception or discontinue nursing.
Excreted in breast milk in small amounts (estrogen M/P ratio ~0.2, progestin M/P ratio ~0.6). May reduce milk quantity and quality. Use caution; generally not recommended. No adverse effects reported in infants at typical doses.
Contraindicated in pregnancy. No dose adjustments are applicable; drug should be discontinued immediately upon confirmed or suspected pregnancy.
Contraindicated; no dose adjustment needed because drug should be discontinued immediately if pregnancy occurs. Pharmacokinetic changes in pregnancy (increased clearance, volume of distribution) not applicable due to contraindication.
Nordette-28 is a combination oral contraceptive containing ethinyl estradiol and levonorgestrel. In case of missed pills, follow package instructions; if two or more pills are missed, use backup contraception for 7 days. The risk of venous thromboembolism is increased in smokers over age 35; strongly advise smoking cessation. Start the first pill on the first day of menses or first Sunday after onset. Monitor for breakthrough bleeding, especially in the first few cycles. Grapefruit juice may increase ethinyl estradiol levels; avoid large quantities.
Estrostep Fe is a combined oral contraceptive containing norethindrone acetate and ethinyl estradiol. It is unique among OCPs for its step-up estrogen regimen (20, 30, 35 mcg EE) intended to mimic natural menstrual cycle. Clinicians should note that it is not FDA-approved for acne treatment, though it is often used off-label; only Estrostep (non-Fe) is approved for acne. The iron (ferrous fumarate) in the last 7 tablets is a placebo. It is a low-dose pill; missed doses more likely cause breakthrough bleeding. Contraindications include smoking >35, history of DVT/PE, migraine with aura, liver disease, breast cancer. Counsel patients to take at same time daily; if missed, follow standard missed pill protocol.
Take one pill daily at the same time each day to maintain hormone levels.,If you miss a pill, take it as soon as remembered; if more than 24 hours late, follow package directions and use backup contraception.,Do not smoke while taking this medication, especially if over 35, due to increased risk of blood clots.,Use additional non-hormonal contraception if you vomit or have severe diarrhea within 3-4 hours of taking a pill.,Nordette-28 does not protect against sexually transmitted infections; use condoms for STI prevention.
Take one pill at the same time each day. The first 21 pills contain active hormones; the last 7 pills are iron tablets (not hormones).,If you miss a pill, refer to the package insert or contact your healthcare provider. Use backup contraception (condoms) if pills are missed.,Common side effects include nausea, breast tenderness, headache, and breakthrough bleeding, especially in the first few months.,Estrostep Fe does not protect against sexually transmitted infections (STIs). Always use condoms for STI prevention.,Smoking while using this pill increases risk of serious cardiovascular events. Do not smoke.,Contact your doctor if you experience signs of a blood clot: sudden leg pain/swelling, chest pain, shortness of breath, or sudden severe headache.,The iron in the last 7 pills is to help with iron levels but does not provide hormonal contraception during that week.
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 NORDETTE-28 vs ESTROSTEP FE, answered by our medical review team.
NORDETTE-28 is a Combined Oral Contraceptive that works by Combined estrogen-progestin oral contraceptive. Suppresses gonadotropin (FSH, LH) release from pituitary, inhibiting ovulation. Increases cervical mucus viscosity and alters endometrial lining.. ESTROSTEP FE is a Combined Oral Contraceptive that works by Combination estrogen-progestin contraceptive: ethinyl estradiol suppresses gonadotropin release via negative feedback on hypothalamic-pituitary axis; norethindrone acetate produces progestational effects including endometrial transformation and cervical mucus thickening, inhibiting sperm penetration and implantation.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between NORDETTE-28 and ESTROSTEP FE depend on the specific clinical indication. These are both Combined 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 NORDETTE-28 is: One tablet orally once daily for 28 consecutive days.. The standard adult dose of ESTROSTEP FE is: One tablet daily orally, each tablet contains norethindrone acetate 1 mg and ethinyl estradiol 20 mcg (24 active tablets) followed by ferrous fumarate 75 mg tablets (4 placebo 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 NORDETTE-28 and ESTROSTEP FE 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. NORDETTE-28 is classified as Category C. FDA Pregnancy Category X. Estrogens and progestins are contraindicated in pregnancy due to risk of fetal harm, including cardiovascular defects and limb reduction defects. Use duri. ESTROSTEP FE is classified as Category C. Category X. Estrostep FE (norethindrone acetate/ethinyl estradiol/ferrous fumarate) is contraindicated in pregnancy. First trimester: increased risk of neural tube defects, cardiov. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.