Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
LYBREL 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 and ethinyl estradiol: suppression of gonadotropins (FSH and LH) via negative feedback, inhibiting ovulation; thickening of cervical mucus to impede sperm penetration; alteration of endometrium to reduce implantation likelihood.
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 (levonorgestrel 0.1 mg/ethinyl estradiol 0.02 mg) orally once daily for 21 days, followed by 7 placebo tablets for 28-day cycle.
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: 27 ± 8 hours; requires ~5 days to reach steady-state; clinical significance: missed doses lead to rapid loss of contraceptive efficacy.
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: primarily metabolized via reduction, hydroxylation, and conjugation; CYP3A4 involvement. Ethinyl estradiol: metabolized by CYP3A4 and undergoes glucuronidation and sulfation.
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: 50-60% as metabolites, ~20% as parent drug; fecal: 30-40%; biliary: 10-20%.
Renal excretion of metabolites and unchanged drug: ~30% (levonorgestrel) and ~20% (ethinyl estradiol) in urine; biliary/fecal elimination: ~40-50% as conjugates and metabolites.
99% bound to 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.
Vd: 1.7 ± 0.3 L/kg; indicates extensive tissue distribution (e.g., reproductive organs, liver).
Levonorgestrel: Vd ~1.8 L/kg (suggesting extensive tissue distribution). Ethinyl estradiol: Vd ~2.4 L/kg.
Oral: 88% (range 80-95%); first-pass metabolism reduces systemic exposure by ~12%.
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 studied in severe renal impairment (GFR <30 m L/min); use not recommended.
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 Child-Pugh class B and C hepatic impairment. Use with caution in Child-Pugh class A; monitor liver function.
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 pediatric patients for oral contraception. Use same dosing as adults for appropriate indications.
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 age-specific 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 risk of serious cardiovascular events from combination oral contraceptive use. Risk increases with age (especially in women >35 years) and with number of cigarettes smoked. Women who use oral contraceptives should be strongly advised not to smoke.
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.
Thrombotic disorders and cardiovascular events (especially in smokers >35 years),Elevated blood pressure,Gallbladder disease,Hepatic neoplasia,Glucose intolerance,Hereditary angioedema,Chloasma,Ocular changes (e.g., retinal thrombosis) requiring discontinuation
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.
Renal or hepatic impairment,Known or suspected pregnancy,Undiagnosed abnormal uterine bleeding,History of or current thromboembolic disorders (e.g., DVT, PE),Cerebrovascular or coronary artery disease,Known or suspected breast carcinoma,Estrogen-dependent neoplasia,Active liver disease (e.g., acute viral hepatitis),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
No specific foods are known to interact with Lybrel. Grapefruit juice may slightly increase ethinyl estradiol levels but effect is not clinically significant. Avoid St. John's wort as it may reduce contraceptive efficacy.
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.
Combined hormonal contraceptives (CHCs) like Lybrel (levonorgestrel/ethinyl estradiol) are contraindicated in pregnancy due to potential fetal harm. First trimester exposure is associated with a slightly increased risk of congenital anomalies, particularly cardiovascular and limb defects, though absolute risk is low. Second and third trimester exposure may lead to adverse outcomes including fetal growth restriction, preterm birth, and neonatal withdrawal symptoms. Data from observational studies suggest no major teratogenic risk at typical contraceptive doses, but use is not recommended once pregnancy is confirmed.
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.
Small amounts of ethinyl estradiol and levonorgestrel are excreted in breast milk. The M/P ratio for ethinyl estradiol is approximately 0.05-0.1; for levonorgestrel, it is about 0.1-0.3. Combined hormonal contraceptives may reduce milk production and composition, especially in early postpartum period. Lybrel is not recommended during breastfeeding until weaning, or for at least 6 months postpartum if breastfeeding is established. Progestin-only contraceptives are preferred.
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.
Lybrel is contraindicated in pregnancy; no dose adjustment is indicated as it should be discontinued immediately upon pregnancy diagnosis. Pharmacokinetic changes in pregnancy (e.g., increased clearance of ethinyl estradiol and levonorgestrel) are not relevant as the drug is not used therapeutically during pregnancy.
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.
Lybrel is a continuous combined oral contraceptive (COC) containing levonorgestrel 90 mcg and ethinyl estradiol 20 mcg, designed to eliminate monthly withdrawal bleeding. It is taken daily without placebo pills. Breakthrough bleeding and spotting are common in the first 6–12 months. Patients should be counseled that amenorrhea may take up to a year to achieve. Lybrel does not protect against STIs. It is contraindicated in smokers over 35, hypertension (≥160/100 mm Hg), migraine with aura, and thromboembolic disorders. Drug interactions with CYP3A4 inducers (e.g., rifampin, carbamazepine, St. John's wort) may reduce efficacy.
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 pill every day at the same time, with or without food. There are no placebo pills, so you will take an active pill daily.,You may experience irregular bleeding or spotting, especially during the first 6–12 months. This is normal and usually decreases over time.,Do not expect a regular menstrual period. Most women will have no bleeding after one year of use.,If you miss pills, follow the package instructions. Missing pills increases the risk of pregnancy and may cause bleeding.,Use a backup method of contraception (like condoms) if you miss two or more pills or start a new pack late.,This medication does not protect against HIV or other sexually transmitted infections.,Tell your healthcare provider if you have new or severe headaches, chest pain, leg pain, vision changes, or jaundice.,Do not smoke while taking this medication, as smoking increases the risk of serious cardiovascular side effects.,Inform all healthcare providers that you are taking Lybrel, especially before surgery or blood tests.,Store at room temperature away from moisture and heat.
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 LYBREL vs ALTAVERA, answered by our medical review team.
LYBREL is a Oral Contraceptive that works by Combination of levonorgestrel and ethinyl estradiol: suppression of gonadotropins (FSH and LH) via negative feedback, inhibiting ovulation; thickening of cervical mucus to impede sperm penetration; alteration of endometrium to reduce implantation likelihood.. 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 LYBREL 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 LYBREL is: One tablet (levonorgestrel 0.1 mg/ethinyl estradiol 0.02 mg) orally once daily for 21 days, followed by 7 placebo tablets for 28-day cycle.. 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 LYBREL 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. LYBREL is classified as Category C. Combined hormonal contraceptives (CHCs) like Lybrel (levonorgestrel/ethinyl estradiol) are contraindicated in pregnancy due to potential fetal harm. First trimester exposure is ass. 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.