Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
NORETHIN 1/35E-28 vs ESTARYLLA
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. Ethinyl estradiol suppresses FSH and LH, preventing ovulation. Norethindrone alters cervical mucus and endometrial lining, inhibiting sperm penetration and implantation.
Estarylla is a combination oral contraceptive containing ethinyl estradiol and norgestimate. It suppresses gonadotropin release (FSH and LH) via estrogen and progestin, inhibiting ovulation. Additionally, it increases cervical mucus viscosity and alters endometrial receptivity, impeding sperm penetration and implantation.
Prevention of pregnancy
FDA-approved: Prevention of pregnancy in women who elect to use oral contraceptives as a method of contraception.,Off-label: Acne vulgaris (for norgestimate-containing pills), management of menstrual disorders (e.g., dysmenorrhea, abnormal uterine bleeding), hormone therapy for transgender women (non-standardized).,Note: Off-label uses are not FDA-approved for this specific formulation.
One tablet orally once daily for 28 days (21 active tablets containing norethindrone 1 mg and ethinyl estradiol 35 mcg, followed by 7 inert tablets).
One tablet (0.02 mg ethinyl estradiol and 0.15 mg desogestrel) orally once daily for 21 days, followed by 7 days of placebo. Hormone-free interval of 7 days.
Norethindrone: terminal elimination half-life approximately 8-11 hours. Ethinyl estradiol: terminal elimination half-life approximately 10-20 hours (mean ~13 hours). Clinical context: Steady-state achieved within 5 days; once-daily dosing maintains therapeutic levels.
Terminal elimination half-life of ethinyl estradiol is approximately 13-16 hours; clinical context: steady-state achieved within 5-7 days
Hepatic: ethinyl estradiol undergoes CYP3A4-mediated hydroxylation and glucuronidation; norethindrone metabolized via reduction and conjugation.
Ethinyl estradiol is primarily metabolized by CYP3A4, with conjugation to glucuronides and sulfates. Norgestimate is rapidly metabolized to its active metabolite, norelgestromin, and further to levonorgestrel; involvement of CYP2C19 and CYP3A4 in norgestimate metabolism is noted.
Norethindrone is excreted primarily in urine as glucuronide and sulfate conjugates, with about 50-60% excreted renally; approximately 20-30% is excreted in feces via biliary elimination. Ethinyl estradiol is excreted in urine (40-60%) and feces (20-40%) after enterohepatic recirculation.
Renal: ~55% as metabolites, ~27% unchanged; Fecal: ~45% as metabolites
Norethindrone: ~97% bound, primarily to serum albumin and sex hormone-binding globulin (SHBG). Ethinyl estradiol: ~98% bound, primarily to albumin, with slight binding to SHBG.
Ethinyl estradiol: 97-98% bound to albumin, with minor binding to sex hormone-binding globulin
Norethindrone: Vd approximately 3-4 L/kg (distributes widely into body tissues). Ethinyl estradiol: Vd approximately 1.5-2.5 L/kg (moderately distributed, concentrated in reproductive tissues).
Ethinyl estradiol: approximately 2.8 L/kg; indicates extensive tissue distribution
Oral: Norethindrone: ~64% (due to first-pass metabolism). Ethinyl estradiol: ~40-60% (due to first-pass metabolism and variable absorption).
Oral: approximately 55% due to first-pass metabolism; consistent in healthy females
No dose adjustment required for mild to moderate renal impairment. Not studied in severe renal impairment; consider alternative contraception.
No dose adjustment required for mild to moderate renal impairment. Not recommended for use in severe renal impairment or end-stage renal disease due to lack of data.
Contraindicated in Child-Pugh class B or C (moderate to severe hepatic impairment). Use with caution in Child-Pugh class A; monitor liver function.
Contraindicated in Child-Pugh class B and C (moderate to severe hepatic impairment). Use with caution in Child-Pugh class A; dose adjustment not specifically defined, but alternative contraception recommended.
Postmenarchal adolescents: same dosing as adults (one tablet daily for 28-day cycle). Use only after menarche; not indicated before.
Approved for use in postmenarchal adolescents: same dosing as adults (one tablet daily for 21 days, then 7 days placebo). No weight-based dosing required.
Not indicated for use in postmenopausal women. No specific geriatric dose; estrogen-containing contraceptives are not appropriate in this population due to increased risk of thromboembolism and cardiovascular events.
Not indicated in postmenopausal women. No specific geriatric dosing; contraindicated in women over 60 years due to increased thromboembolic risk.
Cigarette smoking increases risk of serious cardiovascular events. Women over 35 who smoke should not use combination oral contraceptives.
Cigarette smoking increases the risk of serious cardiovascular side effects from combination oral contraceptives. This risk increases with age (especially in women over 35 years of age) and with the number of cigarettes smoked. Women who use combination hormonal contraceptives should be strongly advised not to smoke.
Increased risk of thromboembolic disorders, stroke, MI, especially in smokers,Hepatic neoplasia,Gallbladder disease,Hypertension,Worsening of migraine,Depression,Fluid retention,Carbohydrate/lipid effects
Thrombotic disorders: Increased risk of venous thromboembolism (VTE) and arterial thromboembolism (e.g., MI, stroke). Discontinue if thrombotic event occurs.,Cardiovascular disease: Avoid in women with uncontrolled hypertension, diabetes with vascular involvement, or history of thromboembolic disease.,Cigarette smoking: Strongly advise cessation, especially in women over 35.,Liver disease: Discontinue if jaundice or cholestasis develops; contraindicated in acute viral hepatitis or severe cirrhosis.,Hormone-dependent malignancies: Increased risk of breast cancer (current use) and cervical cancer; avoid if known or suspected breast cancer.,Gallbladder disease: Increased risk of gallstones.,Carbohydrate and lipid metabolism: Monitor glucose and lipids in predisposed patients; may impair glucose tolerance and increase triglycerides.,Headache: Evaluate if new-onset or worsening migraine, especially with focal neurological symptoms.,Uterine bleeding: Rule out pregnancy if amenorrhea occurs; irregular bleeding may require evaluation.,Depression: Monitor for mood changes; discontinue if severe depression recurs.,Angioedema: Risk in women with hereditary angioedema.
Thrombophlebitis or thromboembolic disorders,Cerebrovascular or coronary artery disease,Known or suspected breast carcinoma,Estrogen-dependent neoplasia,Undiagnosed abnormal genital bleeding,Pregnancy,Known or suspected pregnancy,Hepatic adenoma or carcinoma,Active liver disease (if LFTs not returned to normal),Hypersensitivity to any component
Known or suspected pregnancy,Current or past venous thrombosis (e.g., deep vein thrombosis, pulmonary embolism),Current or past arterial thrombosis (e.g., myocardial infarction, stroke) or prodromal conditions (e.g., angina, transient ischemic attack),Known thrombophilic disorders (e.g., Factor V Leiden, prothrombin mutation, antithrombin deficiency),History of cerebrovascular or coronary artery disease,Uncontrolled hypertension (sustained >160/100 mm Hg),Diabetes mellitus with nephropathy, retinopathy, neuropathy, or other vascular disease,Headaches with focal neurological symptoms (e.g., migraine with aura) in women over 35,Current or past breast cancer, or other estrogen- or progestin-sensitive cancer,Active liver disease (e.g., acute viral hepatitis, severe cirrhosis) or benign/malignant liver tumors,Undiagnosed abnormal uterine bleeding,Hypersensitivity to any component of Estarylla,Use of highly active antiretroviral therapy (HAART) containing ritonavir or direct-acting antivirals for hepatitis C (e.g., ombitasvir/paritaprevir/ritonavir) due to potential for hepatotoxicity
No significant food interactions. Grapefruit juice may slightly increase ethinyl estradiol levels but not clinically relevant. Consistent intake recommended to maintain steady hormone levels.
There are no known significant food interactions. Grapefruit juice may increase estrogen levels but clinical significance is unclear; consider moderate intake.
Pregnancy category X. First trimester: major congenital anomalies including limb defects, neural tube defects, and cardiovascular anomalies. Second and third trimesters: increased risk of fetal genital abnormalities (e.g., clitoral hypertrophy, labial fusion in females, ambiguous genitalia in males), and potential long-term neurodevelopmental effects.
Estarylla (ethinyl estradiol/levonorgestrel) is a combined oral contraceptive. Use during pregnancy is contraindicated. First trimester: No strong evidence of major malformations from inadvertent exposure, but increased risk of cardiovascular and limb defects in some studies. Second and third trimesters: Associated with fetal harm, including cardiovascular effects (e.g., congenital heart defects) and possible estrogenic effects, though data are limited. Postnatal effects: Potential long-term developmental effects unknown. Overall risk is low but not zero; avoid use in pregnancy.
Excreted in human breast milk; can reduce milk production and affect infant development. M/P ratio not established. Contraindicated in breastfeeding.
Estarylla is excreted in breast milk in small amounts (ethinyl estradiol: M/P ratio ~0.2; levonorgestrel: M/P ratio ~0.3-0.4). Combined hormonal contraceptives may reduce milk production and affect milk composition, especially in early postpartum. Use is generally not recommended until breastfeeding is well-established (at least 6 weeks postpartum). For later use, progestin-only methods are preferred. Monitor infant for jaundice and growth.
No established safe dose; contraindicated in pregnancy. Pharmacokinetic changes during pregnancy (e.g., increased clearance, volume of distribution) do not permit any therapeutic use; alternative agents recommended.
Estarylla is contraindicated in pregnancy. No dosing adjustments are recommended because it should not be used. Pregnancy alters pharmacokinetics of oral contraceptives (e.g., increased volume of distribution, altered hepatic metabolism), but no dose changes are indicated due to contraindication. If inadvertently taken, discontinue immediately.
Norethindrone 1 mg/ethinyl estradiol 35 mcg is a monophasic oral contraceptive. Counsel patients that breakthrough bleeding is common in first 3 cycles. If pregnancy occurs, exclude ectopic pregnancy as progestins may slow tubal motility. Monitor for hypertension and hyperkalemia in patients on spironolactone or ACE inhibitors.
Estarylla is a combination oral contraceptive containing ethinyl estradiol and norgestimate. It is indicated for prevention of pregnancy. Monitor for thromboembolic events, especially in smokers over 35. Counsel on missed dose management: take as soon as remembered, use backup contraception if more than 24 hours late. May reduce menstrual cramps and acne. Not recommended in patients with history of estrogen-dependent neoplasia, liver disease, or uncontrolled hypertension.
Take one tablet daily at the same time, even if no bleeding expected.,Missed dose: if within 12 hours, take immediately; if >12 hours, take and use backup contraception for 7 days.,Common side effects include nausea, breast tenderness, breakthrough bleeding, and headaches.,Do not smoke while on this medication due to increased risk of blood clots.,Seek medical help for sudden leg pain, chest pain, vision changes, or severe headache.
Take one pill daily at the same time each day.,If you miss a pill, take it as soon as remembered; use backup contraception if more than 24 hours late.,Do not smoke while taking this medication, especially if over 35.,Report any signs of blood clots: leg pain, chest pain, shortness of breath, or sudden vision changes.,This medication does not protect against HIV or other STDs.
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 NORETHIN 1/35E-28 vs ESTARYLLA, answered by our medical review team.
NORETHIN 1/35E-28 is a Combined Oral Contraceptive that works by Combination estrogen-progestin oral contraceptive. Ethinyl estradiol suppresses FSH and LH, preventing ovulation. Norethindrone alters cervical mucus and endometrial lining, inhibiting sperm penetration and implantation.. ESTARYLLA is a Combined Oral Contraceptive that works by Estarylla is a combination oral contraceptive containing ethinyl estradiol and norgestimate. It suppresses gonadotropin release (FSH and LH) via estrogen and progestin, inhibiting ovulation. Additionally, it increases cervical mucus viscosity and alters endometrial receptivity, impeding sperm penetration and implantation.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between NORETHIN 1/35E-28 and ESTARYLLA 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 NORETHIN 1/35E-28 is: One tablet orally once daily for 28 days (21 active tablets containing norethindrone 1 mg and ethinyl estradiol 35 mcg, followed by 7 inert tablets).. The standard adult dose of ESTARYLLA is: One tablet (0.02 mg ethinyl estradiol and 0.15 mg desogestrel) orally once daily for 21 days, followed by 7 days of placebo. Hormone-free interval of 7 days.. 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 NORETHIN 1/35E-28 and ESTARYLLA 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. NORETHIN 1/35E-28 is classified as Category C. Pregnancy category X. First trimester: major congenital anomalies including limb defects, neural tube defects, and cardiovascular anomalies. Second and third trimesters: increased . ESTARYLLA is classified as Category C. Estarylla (ethinyl estradiol/levonorgestrel) is a combined oral contraceptive. Use during pregnancy is contraindicated. First trimester: No strong evidence of major malformations f. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.