Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
NORQUEST FE vs ALTAVERA
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
NORQUEST FE is a combination oral contraceptive containing ethinyl estradiol and norethindrone. Ethinyl estradiol suppresses gonadotropin release, inhibiting ovulation. Norethindrone induces progestational changes in the endometrium, increasing cervical mucus viscosity, and also inhibits ovulation.
Combination of ethinyl estradiol and desogestrel: ethinyl estradiol suppresses gonadotropin release, inhibiting ovulation; desogestrel (progestin) causes cervical mucus thickening and endometrial atrophy, preventing implantation.
Prevention of pregnancy
Prevention of pregnancy,Treatment of moderate acne vulgaris (in females ≥15 years with no contraindications)
One tablet orally once daily, each tablet containing 1 mg norethindrone acetate and 20 mcg ethinyl estradiol (21 active tablets) followed by 7 ferrous fumarate tablets.
1 tablet (ethinyl estradiol 0.03 mg / levonorgestrel 0.15 mg) orally once daily for 21 days, followed by 7 placebo days.
Terminal half-life: 6-8 hours. Clinical context: Supports once-daily dosing with sustained therapeutic effect.
Levonorgestrel: terminal elimination half-life 25±10 hours; ethinyl estradiol: 13±7 hours. Clinical context: steady-state concentrations achieved within 5-7 days; contraceptive efficacy requires consistent daily dosing.
Ethinyl estradiol is metabolized via CYP3A4, with phase II conjugation (glucuronidation and sulfation). Norethindrone is metabolized via reduction and conjugation, primarily as sulfate and glucuronide conjugates.
Ethinyl estradiol: primarily metabolized by CYP3A4; undergoes sulfation and glucuronidation. Desogestrel: rapidly converted to active metabolite etonogestrel via CYP2C9 and CYP2C19; further metabolism by CYP3A4.
Renal: 80% (50% unchanged, 30% as metabolites); Fecal: 19%; Biliary: <1%
Renal excretion of metabolites and unchanged drug: ~30% (levonorgestrel) and ~20% (ethinyl estradiol) in urine; biliary/fecal elimination: ~40-50% as conjugates and metabolites.
97% bound to albumin and α1-acid glycoprotein.
Levonorgestrel: 98-99% bound to sex hormone-binding globulin (SHBG) and albumin; ethinyl estradiol: 98% bound to albumin.
Vd: 3.5 L/kg (~245 L for 70 kg adult). Indicates extensive tissue distribution.
Levonorgestrel: Vd ~1.8 L/kg (suggesting extensive tissue distribution). Ethinyl estradiol: Vd ~2.4 L/kg.
Oral: 92% (range 88-96%)
Oral bioavailability: levonorgestrel ~100% (nearly complete); ethinyl estradiol ~45-50% (first-pass hepatic metabolism).
No dose adjustment required for mild to moderate renal impairment. Not recommended for use in severe renal impairment (GFR <30 m L/min) due to lack of data.
No dose adjustment required for mild to moderate renal impairment. Contraindicated in severe renal disease or acute renal failure due to potential fluid retention.
Contraindicated in patients with hepatic impairment (Child-Pugh Class B or C). No specific dose adjustment for mild impairment; use with caution.
Contraindicated in severe hepatic dysfunction (Child-Pugh class B or C). Use caution in mild to moderate impairment (Child-Pugh A); monitor liver enzymes.
Safety and efficacy not established in postmenarchal patients; dosing follows adult regimen if indicated.
Not indicated for use before menarche. For postmenarchal adolescents, same dosing as adults (1 tablet daily, 21/7 regimen) after evaluation of risks.
Not indicated for use in postmenopausal women; no specific dose adjustment recommended due to lack of data.
Not indicated for postmenopausal women. No specific geriatric dosing; consider increased risk of thromboembolism, cardiovascular disease, and metabolic effects in older women of reproductive age.
Cigarette smoking increases the risk of serious cardiovascular events from combination oral contraceptive use. Women over 35 years old who smoke should not use this product.
Cigarette smoking increases risk of serious cardiovascular events from combined oral contraceptives. Risk increases with age (especially >35 years) and with number of cigarettes smoked. Women who use combined hormonal contraceptives should be strongly advised not to smoke.
Increased risk of thromboembolic disorders, cardiovascular disease (especially in smokers over 35), hepatic neoplasia, gallbladder disease, hypertension, and glucose intolerance. Use with caution in women with risk factors for these conditions.
Thrombotic disorders: risk of venous thromboembolism (VTE), stroke, myocardial infarction; discontinue if thrombotic event occurs.,Hepatic disease: discontinue if jaundice or liver function abnormalities develop.,Hypertension: monitor blood pressure; discontinue if uncontrolled.,Carbohydrate metabolism: may affect glucose tolerance; monitor diabetic patients.,Depression: discontinue if significant depression occurs.,Gallbladder disease: increased risk of cholelithiasis.
History of thrombophlebitis or thromboembolic disorders, cerebrovascular or coronary artery disease, known or suspected pregnancy, carcinoma of the breast, estrogen-dependent neoplasia, undiagnosed abnormal genital bleeding, jaundice with prior OCs, liver adenoma or carcinoma, hepatic impairment, and hypersensitivity to any component.
Thrombophlebitis or thromboembolic disorders (current or history),Cerebrovascular or coronary artery disease (current or history),Known or suspected breast carcinoma,Estrogen-dependent neoplasia (known or suspected),Undiagnosed abnormal genital bleeding,Cholestatic jaundice of pregnancy or jaundice with prior pill use,Hepatic adenoma or carcinoma (known or suspected),Pregnancy (known or suspected),Hypersensitivity to any component
Avoid calcium-rich foods (milk, yogurt, cheese) within 2 hours of dose. Vitamin C (citrus fruits, tomatoes) enhances iron absorption. Coffee, tea, and red wine reduce iron absorption; avoid within 1 hour of dosing.
No significant food interactions. Alcohol does not affect efficacy but may increase risk of adverse effects such as nausea. Grapefruit juice has no known interaction. Avoid excessive alcohol consumption due to potential hepatotoxicity.
Pregnancy category X. Contraindicated in pregnancy due to risk of fetal harm. First trimester: estrogen exposure associated with congenital anomalies including cardiovascular and neural tube defects. Second/third trimesters: linked to vaginal adenosis and cervical dysplasia in female offspring, potential for genitourinary abnormalities. Use of iron and calcium components generally safe, but hormonal components (estrogen/norethindrone) pose teratogenic risk.
ALTAVERA contains ethinyl estradiol and levonorgestrel. First trimester: Inadvertent exposure during organogenesis is associated with a very low absolute risk of cardiovascular defects (relative risk 1.2-1.4) and no consistent increase in other major malformations. Second and third trimesters: No known teratogenic effects, but theoretical risks from estrogenic effects (e.g., feminization of male fetus). Postnatal: No increased risk of long-term developmental effects from pregnancy exposure.
Not recommended during breastfeeding. Estrogen and progestin may reduce milk production and quality. Small amounts of steroids and iron are excreted in breast milk; M/P ratio not established for combined hormonal contraceptives. No specific data for NORQUEST FE; avoid use.
Combined oral contraceptives may reduce milk production and quality, especially in early lactation. Ethinyl estradiol transfers into breast milk at low levels (M/P ratio approximately 0.1-0.2), excluding clinical effects in term infants. Levonorgestrel transfer is minimal (M/P ratio ~0.2-0.4). Use is generally avoided in breastfeeding women, especially during the first 6 weeks postpartum. Progestin-only methods are preferred.
Contraindicated in pregnancy; no dose adjustments recommended as drug should be discontinued. Pharmacokinetic changes in pregnancy (increased volume of distribution, altered hepatic metabolism) would necessitate dose increase if used, but use is contraindicated.
Contraindicated in pregnancy. No dose adjustment recommended because use is discontinued upon confirmed or suspected pregnancy. Pharmacokinetic changes in pregnancy (e.g., increased hepatic clearance, altered binding proteins) are not relevant for this indication.
Contains norethindrone acetate and ethinyl estradiol. Use for iron deficiency anemia due to menstrual blood loss; iron absorption enhanced with vitamin C. Monitor for thromboembolic events, especially in smokers over 35. May reduce menstrual flow and improve iron stores over 3-6 months.
ALTAVERA is a combined oral contraceptive (COC) containing ethinylestradiol and levonorgestrel. It inhibits ovulation via suppression of gonadotropins. Counsel patients to take at the same time daily to maintain efficacy. Missed pill management: if missed within 12 hours, take immediately; if >12 hours, take last missed pill and use backup contraception for 7 days. Be aware of increased VTE risk, especially in smokers over 35. May reduce effectiveness of lamotrigine; monitor seizure control. Initiate on the first day of menses or first Sunday after onset.
Take one tablet daily at the same time with food to reduce nausea.,Iron may cause dark stools; this is harmless.,Avoid taking with dairy, calcium supplements, or antacids within 2 hours.,Report signs of blood clots: leg pain, chest pain, shortness of breath.,Continue for full course even if bleeding improves to prevent recurrence.
Take one tablet daily at the same time each day, with or without food.,If you miss a pill by less than 12 hours, take it as soon as you remember. If more than 12 hours, take the missed pill and use a backup method (e.g., condoms) for the next 7 days.,Smoking increases your risk of serious cardiovascular side effects, especially if you are over 35 years old. Do not smoke while taking this medication.,Seek immediate medical attention if you experience sudden severe headache, chest pain, leg pain/swelling, or vision changes (symptoms of blood clots).,This medication does not protect against HIV or other sexually transmitted infections.,If you are taking lamotrigine or other anticonvulsants, tell your doctor; your seizure medication may be less effective.,Store at room temperature away from moisture and heat.
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 NORQUEST FE vs ALTAVERA, answered by our medical review team.
NORQUEST FE is a Oral Contraceptive that works by NORQUEST FE is a combination oral contraceptive containing ethinyl estradiol and norethindrone. Ethinyl estradiol suppresses gonadotropin release, inhibiting ovulation. Norethindrone induces progestational changes in the endometrium, increasing cervical mucus viscosity, and also inhibits ovulation.. ALTAVERA is a Combined Oral Contraceptive that works by Combination of ethinyl estradiol and desogestrel: ethinyl estradiol suppresses gonadotropin release, inhibiting ovulation; desogestrel (progestin) causes cervical mucus thickening and endometrial atrophy, preventing implantation.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between NORQUEST FE and ALTAVERA 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 NORQUEST FE is: One tablet orally once daily, each tablet containing 1 mg norethindrone acetate and 20 mcg ethinyl estradiol (21 active tablets) followed by 7 ferrous fumarate tablets.. The standard adult dose of ALTAVERA is: 1 tablet (ethinyl estradiol 0.03 mg / levonorgestrel 0.15 mg) orally once daily for 21 days, followed by 7 placebo 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 NORQUEST FE and ALTAVERA 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. NORQUEST FE is classified as Category C. Pregnancy category X. Contraindicated in pregnancy due to risk of fetal harm. First trimester: estrogen exposure associated with congenital anomalies including cardiovascular and n. ALTAVERA is classified as Category C. ALTAVERA contains ethinyl estradiol and levonorgestrel. First trimester: Inadvertent exposure during organogenesis is associated with a very low absolute risk of cardiovascular def. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.