Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
NORDETTE-28 vs AFIRMELLE
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 oral contraceptive containing ethinyl estradiol and levonorgestrel. Inhibits ovulation by suppressing gonadotropin release (FSH and LH). Also increases cervical mucus viscosity and alters endometrial receptivity.
Prevention of pregnancy
Prevention of pregnancy (FDA-approved)
One tablet orally once daily for 28 consecutive days.
One tablet (0.1 mg levonorgestrel, 0.02 mg ethinyl estradiol) orally once daily for 21 days, followed by 7 days of placebo.
Ethinyl estradiol: 13-27 hours (mean 17 hours); Levonorgestrel: 11-45 hours (mean 24 hours); clinical context: steady-state reached after 5-7 days.
Terminal elimination half-life: 12–15 hours. Steady-state achieved within 5 days with Q12H dosing.
Ethinylestradiol is metabolized primarily via CYP3A4; levonorgestrel is metabolized via CYP3A4 and to a lesser extent CYP2C19 and CYP2C9.
Ethinyl estradiol undergoes first-pass metabolism in gut and liver via CYP3A4, with conjugation to sulfate and glucuronide. Levonorgestrel is metabolized primarily by CYP3A4 to reduced and hydroxylated metabolites, then conjugated.
Renal: ~50% as metabolites, ~20% unchanged; Fecal: ~30% as metabolites; Biliary: minimal.
Renal: 50% as unchanged drug and metabolites; fecal: 40% as metabolites; biliary: ~10% as glucuronide conjugates.
Ethinyl estradiol: ~97% bound to albumin; Levonorgestrel: ~98% bound to SHBG (sex hormone-binding globulin) and albumin.
~99% bound to serum albumin and sex hormone-binding globulin.
Ethinyl estradiol: 2.9-4.3 L/kg; Levonorgestrel: 1.8-2.1 L/kg; clinical meaning: extensive tissue distribution, not limited to plasma.
2.8 L/kg (apparent Vd), indicating extensive tissue distribution.
Oral: Ethinyl estradiol ~45% (first-pass metabolism); Levonorgestrel ~100% (minimal first-pass).
Oral: ~70% due to first-pass metabolism.
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 required for mild to moderate renal impairment. Not recommended for use in end-stage renal disease.
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 acute hepatic disease or severe (Child-Pugh C) hepatic impairment. Use with caution in mild to moderate hepatic impairment; monitor liver function.
Not indicated for use in pediatric patients before menarche. For postmenarchal adolescents, same dosing as adults: one tablet orally daily for 28 days.
Not indicated for use before menarche. Post-menarche: same as adult dosing (one tablet daily) based on adult clinical trials.
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 postmenopausal women; no specific dose adjustment required in healthy elderly, but limited data available.
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 contraceptive use. Risk increases with age (especially in women over 35) and with heavy smoking (15+ cigarettes/day). Women who use combination hormonal contraceptives should be strongly advised not to smoke.
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
Thrombotic disorders (venous thromboembolism, stroke, myocardial infarction),Cigarette smoking (increases cardiovascular risk),Hypertension (especially in women with renal disease or migraines),Gallbladder disease,Hepatic neoplasia (benign and malignant),Carbohydrate and lipid metabolism effects,Ocular lesions (retinal thrombosis),Depressed mood or depression,Uterine bleeding irregularities,Reduced efficacy with hepatic enzyme inducers
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 (current or history),Cerebrovascular or coronary artery disease (current or history),Known or suspected breast cancer, endometrial cancer, or other estrogen-dependent neoplasia,Undiagnosed abnormal genital bleeding,Cholestatic jaundice of pregnancy or jaundice with prior oral contraceptive use,Hepatic adenoma or carcinoma (current or history),Known or suspected pregnancy,Hypersensitivity to any component of the product,Heavy smoking (≥15 cigarettes/day) in women over 35
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.
Grapefruit juice may increase ethinyl estradiol levels; avoid large quantities. No significant food restrictions. Administer with food if GI upset occurs.
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.
Pregnancy category X. Contraindicated in pregnancy due to risk of fetal harm. First trimester: exposure associated with congenital anomalies (e.g., cardiovascular, neural tube defects). Second and third trimesters: increased risk of fetal growth restriction, preterm birth, and neonatal respiratory distress. Postnatal: possible long-term developmental effects.
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.
Contraindicated during breastfeeding. Small amounts of ethinyl estradiol and norethindrone are excreted in breast milk; M/P ratio not well defined. Potential for adverse effects on infant (e.g., jaundice, breast enlargement). May reduce milk production and quality.
Contraindicated in pregnancy. No dose adjustments are applicable; drug should be discontinued immediately upon confirmed or suspected pregnancy.
Contraindicated in pregnancy; no dose adjustment recommended. If exposure occurs, immediate discontinuation is required. No pharmacokinetic data support safe use; avoid use entirely.
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.
Afirmelle (levonorgestrel/ethinyl estradiol) is a combined oral contraceptive. Counsel patients to take at the same time daily to maintain consistent hormone levels. Use back-up contraception if a dose is missed. Monitor for signs of thromboembolism, especially in smokers over 35. Advise that certain antibiotics (e.g., rifampin) and anticonvulsants (e.g., phenytoin) may reduce efficacy. Consider progestin-only pill if contraindications to estrogen exist.
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 every day, even if you don't have sex.,If you miss a pill, follow the instructions in the package insert or ask your healthcare provider.,Use a backup method (like condoms) if you start late or miss pills.,This medication does not protect against HIV or other sexually transmitted infections.,Common side effects include nausea, breast tenderness, and breakthrough bleeding.,Seek medical help if you have symptoms of a blood clot: sudden chest pain, leg swelling, or shortness of breath.,Smoking while on this pill increases your risk of serious cardiovascular events.
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 AFIRMELLE, 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.. AFIRMELLE is a Combined Oral Contraceptive that works by Combination oral contraceptive containing ethinyl estradiol and levonorgestrel. Inhibits ovulation by suppressing gonadotropin release (FSH and LH). Also increases cervical mucus viscosity and alters endometrial receptivity.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between NORDETTE-28 and AFIRMELLE 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 AFIRMELLE is: One tablet (0.1 mg levonorgestrel, 0.02 mg ethinyl estradiol) orally once daily for 21 days, followed by 7 days of placebo.. 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 AFIRMELLE 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. AFIRMELLE is classified as Category C. Pregnancy category X. Contraindicated in pregnancy due to risk of fetal harm. First trimester: exposure associated with congenital anomalies (e.g., cardiovascular, neural tube defe. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.