Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
HAILEY FE 1/20 vs AFIRMELLE
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Combination oral contraceptive containing ethinyl estradiol and norethindrone. Suppresses gonadotropin (FSH and LH) release via negative feedback on the hypothalamic-pituitary-ovarian axis, inhibiting ovulation. Also alters cervical mucus and endometrial lining to impair sperm penetration and implantation.
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.
FDA-approved for prevention of pregnancy.
Prevention of pregnancy (FDA-approved)
One tablet orally once daily for 21 consecutive days followed by 7 days of placebo tablets.
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: approximately 17 ± 5 hours (terminal); Norethindrone: approximately 8 ± 2 hours (terminal). Clinical context: Steady-state reached within 7-10 days; once-daily dosing maintains effective concentrations for contraceptive efficacy.
Terminal elimination half-life: 12–15 hours. Steady-state achieved within 5 days with Q12H dosing.
Ethinyl estradiol is primarily metabolized via CYP3A4 hydroxylation and conjugation (glucuronidation/sulfation). Norethindrone is metabolized by reduction, hydroxylation, and conjugation, primarily via CYP3A4.
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 (approximately 50-60% as metabolites, including glucuronide conjugates of ethinyl estradiol and norethindrone, and about 20% as unchanged norethindrone); Fecal (approximately 30-40% as metabolites); Biliary (minor, with enterohepatic circulation of ethinyl estradiol conjugates).
Renal: 50% as unchanged drug and metabolites; fecal: 40% as metabolites; biliary: ~10% as glucuronide conjugates.
Ethinyl estradiol: approximately 97-98% bound to albumin (primarily) and sex hormone-binding globulin (SHBG); Norethindrone: approximately 93-95% bound to albumin and SHBG.
~99% bound to serum albumin and sex hormone-binding globulin.
Ethinyl estradiol: approximately 2-4 L/kg; Norethindrone: approximately 4-6 L/kg. Clinical meaning: Extensive tissue distribution, with accumulation in adipose tissue and reproductive organs.
2.8 L/kg (apparent Vd), indicating extensive tissue distribution.
Oral: Ethinyl estradiol ~40-45% (first-pass metabolism); Norethindrone ~60-65% (first-pass metabolism).
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 risk of hyperkalemia.
No dose adjustment required for mild to moderate renal impairment. Not recommended for use in end-stage renal disease.
Contraindicated in patients with active liver disease or Child-Pugh class B or C cirrhosis. For Child-Pugh class A, use with caution and monitor liver function.
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 before menarche. For post-menarchal adolescents, same dosing as adults: one tablet orally once daily for 21 days, then 7 days of placebo.
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 geriatric dosing adjustments; consider increased risk of thromboembolic events and cardiovascular disease.
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 (e.g., stroke, myocardial infarction, thromboembolism) from combination oral contraceptives. Risk increases with age (>35 years) and heavy smoking (≥15 cigarettes/day). Women who are >35 years old and 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.
Increased risk of thrombotic disorders including venous thromboembolism, stroke, and myocardial infarction.,Discontinue if sudden partial or complete loss of vision or onset of proptosis, diplopia, migraine.,Elevated blood pressure; use caution in hypertension.,Gallbladder disease; increased risk of gallstones.,Carbohydrate and lipid metabolism effects; use caution in diabetes and hyperlipidemia.,Hepatic neoplasia; discontinue if jaundice or liver dysfunction.,Chloasma; avoid sun or UV exposure.,Bleeding irregularities; may cause breakthrough bleeding and spotting.,Possible decreased efficacy with concomitant enzyme-inducing drugs.
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
Thrombophlebitis or thromboembolic disorders (current or history).,Cerebrovascular or coronary artery disease (current or history).,Known or suspected breast carcinoma or estrogen-dependent neoplasia.,Undiagnosed abnormal genital bleeding.,Pregnancy (known or suspected).,Benign or malignant liver tumor (active or history).,Active liver disease with abnormal liver function.,Hypersensitivity to any component.,Age >35 years with cigarette smoking.
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
No specific food interactions. Grapefruit juice may increase estrogen levels; avoid excessive consumption. St. John's Wort may reduce efficacy. Consistent intake with or without food is recommended to maintain steady-state levels.
Grapefruit juice may increase ethinyl estradiol levels; avoid large quantities. No significant food restrictions. Administer with food if GI upset occurs.
First trimester: No increased risk of major birth defects in large epidemiological studies. Second and third trimesters: Use is not recommended due to potential adverse effects on fetal development, including possible estrogenic effects and association with congenital anomalies in animal studies. Fetal risk cannot be ruled out.
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 breast milk in small amounts. Estrogen and progestin levels may affect milk composition and reduce milk production. M/P ratio not reported; use caution, especially in the immediate postpartum period. Avoid use in breastfeeding women if possible.
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.
No dose adjustment established; use is contraindicated during pregnancy. If inadvertent exposure occurs, discontinue immediately. Pharmacokinetic changes in pregnancy (increased clearance, volume of distribution) do not warrant dose adjustment because the drug is contraindicated.
Contraindicated in pregnancy; no dose adjustment recommended. If exposure occurs, immediate discontinuation is required. No pharmacokinetic data support safe use; avoid use entirely.
Contains ethinyl estradiol 20 mcg and norethindrone 1 mg. Consider lower estrogen dose for patients with estrogen-sensitive migraines or history of thromboembolism. Monitor for breakthrough bleeding, especially in first 3 cycles. CYP3A4 inducers like rifampin may reduce efficacy. Check pregnancy test before initiating if delayed menses. Use with caution in patients with hypertriglyceridemia.
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 tablet daily at the same time, in the order listed on the pack.,If you miss a dose, take it as soon as remembered; if more than 24 hours late, use backup contraception.,Common side effects: nausea, breast tenderness, spotting, and headache.,Report signs of blood clots: sudden leg pain, chest pain, or shortness of breath.,Smoking increases risk of serious cardiovascular side effects, especially if over 35 years old.,Antibiotics (except rifampin) do not reduce effectiveness; inform your provider about all medications.
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 HAILEY FE 1/20 vs AFIRMELLE, answered by our medical review team.
HAILEY FE 1/20 is a Oral Contraceptive that works by Combination oral contraceptive containing ethinyl estradiol and norethindrone. Suppresses gonadotropin (FSH and LH) release via negative feedback on the hypothalamic-pituitary-ovarian axis, inhibiting ovulation. Also alters cervical mucus and endometrial lining to impair sperm penetration and implantation.. 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 HAILEY FE 1/20 and AFIRMELLE depend on the specific clinical indication. These are agents from distinct pharmacological classes and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of HAILEY FE 1/20 is: One tablet orally once daily for 21 consecutive days followed by 7 days of placebo tablets.. 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 HAILEY FE 1/20 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. HAILEY FE 1/20 is classified as Category C. First trimester: No increased risk of major birth defects in large epidemiological studies. Second and third trimesters: Use is not recommended due to potential adverse effects on . 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.