Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
FEMLYV vs ALTAVERA
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Combination of levonorgestrel, a progestin, and ethinyl estradiol, an estrogen; suppresses gonadotropins, inhibits ovulation, alters cervical mucus and endometrium.
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)
FEMLYV (norethindrone acetate/ethinyl estradiol) is administered as one tablet (1 mg norethindrone acetate/20 mcg ethinyl estradiol) orally once daily for 21 days, followed by 7 days of placebo tablets. The dosing regimen is continuous cyclic.
1 tablet (ethinyl estradiol 0.03 mg / levonorgestrel 0.15 mg) orally once daily for 21 days, followed by 7 placebo days.
Terminal elimination half-life is approximately 24-30 hours, supporting once-daily dosing in most patients.
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.
Levonorgestrel: CYP3A4; ethinyl estradiol: CYP3A4, CYP2C9, conjugation.
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.
Primarily renal (approximately 60-70% as metabolites, less than 10% as unchanged drug); fecal excretion accounts for about 20-30%.
Renal excretion of metabolites and unchanged drug: ~30% (levonorgestrel) and ~20% (ethinyl estradiol) in urine; biliary/fecal elimination: ~40-50% as conjugates and metabolites.
Approximately 97-99% bound to plasma proteins, mainly albumin and sex hormone-binding globulin (SHBG).
Levonorgestrel: 98-99% bound to sex hormone-binding globulin (SHBG) and albumin; ethinyl estradiol: 98% bound to albumin.
Apparent volume of distribution is approximately 0.5-1.4 L/kg, suggesting distribution into total body water and some tissue binding.
Levonorgestrel: Vd ~1.8 L/kg (suggesting extensive tissue distribution). Ethinyl estradiol: Vd ~2.4 L/kg.
Oral bioavailability is approximately 50-70% due to first-pass metabolism.
Oral bioavailability: levonorgestrel ~100% (nearly complete); ethinyl estradiol ~45-50% (first-pass hepatic metabolism).
No specific dosing adjustment is recommended based on GFR, as pharmacokinetics are not significantly altered. However, use with caution in patients with renal impairment, especially if fluid retention is a concern.
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 A, B, or C). No dose modification is recommended; alternative contraceptive methods should be considered in patients with hepatic disease.
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 have not been established in pediatric patients below 16 years of age. In postmenarchal adolescents, dosing is the same as adults: one tablet daily for 21 days, then 7 days of placebo.
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 dosing recommendations for elderly patients, as FEMLYV is a contraceptive for women of reproductive age.
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 risk of serious cardiovascular events from COC use. Women over 35 who smoke should not use COCs.
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.
Cardiovascular disorders,Carcinoma of the breast and reproductive organs,Liver disease,Risk of thromboembolism,Elevated blood pressure,Gallbladder disease,Carbohydrate and lipid metabolic effects,Headache,Bleeding irregularities
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.
Breast cancer or other estrogen/progestin-sensitive cancer,Liver tumors or active liver disease,Undiagnosed abnormal uterine bleeding,Pregnancy,Current or history of thrombosis,Cerebrovascular or coronary artery disease,Migraine with aura (if over 35),Cigarette smoking (if over 35)
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
No significant food interactions. Grapefruit juice may slightly increase estrogen levels but not clinically relevant. Avoid high-fat meals if experiencing nausea.
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.
FEMLYV (drospirenone and ethinyl estradiol) is contraindicated in pregnancy due to known risks. First trimester exposure is associated with a small increased risk of neural tube defects and cardiovascular anomalies from the estrogen component. Second and third trimester exposure may lead to fetal harm including feminization of male fetuses, urogenital sinus abnormalities, and potential long-term reproductive tract effects. Postnatal effects such as vaginal adenosis and clear cell adenocarcinoma have been reported with in utero diethylstilbestrol exposure, though relevance to FEMLYV is extrapolated.
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.
FEMLYV components are excreted in human milk. Ethinyl estradiol milk concentration is approximately 1% of maternal serum; drospirenone M/P ratio is not established. Use during lactation may reduce milk production and quality. No data on infant effects; caution advised. Alternative contraception recommended for breastfeeding women.
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.
No dosing adjustments apply as FEMLYV is contraindicated in pregnancy. Pharmacokinetic changes in pregnancy (e.g., increased hepatic clearance, volume of distribution) would theoretically reduce efficacy, but use is not recommended.
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.
FEMLYV is a combined oral contraceptive containing ethinyl estradiol and norgestimate. Monitor for thromboembolic events, especially in smokers over 35. Counsel patients to take at same time daily and to use backup contraception if doses are missed. Efficacy may be reduced with enzyme-inducing drugs.
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 each day.,If you miss a dose, follow the package instructions and use backup contraception.,Smoking increases risk of serious cardiovascular side effects, especially if over 35.,Common side effects include nausea, headache, and breast tenderness; these often improve.,Contact your healthcare provider if you experience leg swelling, chest pain, or severe headache.
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 FEMLYV vs ALTAVERA, answered by our medical review team.
FEMLYV is a Oral Contraceptive that works by Combination of levonorgestrel, a progestin, and ethinyl estradiol, an estrogen; suppresses gonadotropins, inhibits ovulation, alters cervical mucus and endometrium.. 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 FEMLYV 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 FEMLYV is: FEMLYV (norethindrone acetate/ethinyl estradiol) is administered as one tablet (1 mg norethindrone acetate/20 mcg ethinyl estradiol) orally once daily for 21 days, followed by 7 days of placebo tablets. The dosing regimen is continuous cyclic.. 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 FEMLYV 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. FEMLYV is classified as Category C. FEMLYV (drospirenone and ethinyl estradiol) is contraindicated in pregnancy due to known risks. First trimester exposure is associated with a small increased risk of neural tube de. 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.