Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
LOW-OGESTREL-21 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 oral contraceptive. Suppresses gonadotropin release (FSH and LH) via estrogen (ethinyl estradiol) and progestin (norgestrel), inhibiting ovulation. Also increases cervical mucus viscosity and alters 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)
One tablet (norgestrel 0.3 mg/ethinyl estradiol 30 mcg) orally once daily for 21 days, followed by 7 pill-free days.
1 tablet (ethinyl estradiol 0.03 mg / levonorgestrel 0.15 mg) orally once daily for 21 days, followed by 7 placebo days.
Norgestrel: 18-28 hours; ethinyl estradiol: 13-27 hours. Steady-state achieved after 5-7 days.
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.
Hepatic via CYP3A4 isoenzymes (ethinyl estradiol and norgestrel undergo hydroxylation and conjugation). Enterohepatic circulation.
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.
Ethinyl estradiol and norgestrel are excreted primarily as glucuronide and sulfate conjugates in urine (50-60%) and feces (30-40%).
Renal excretion of metabolites and unchanged drug: ~30% (levonorgestrel) and ~20% (ethinyl estradiol) in urine; biliary/fecal elimination: ~40-50% as conjugates and metabolites.
Norgestrel: 93-95% (albumin, SHBG); ethinyl estradiol: 97-98% (albumin).
Levonorgestrel: 98-99% bound to sex hormone-binding globulin (SHBG) and albumin; ethinyl estradiol: 98% bound to albumin.
Norgestrel: 3.5-4.5 L/kg; ethinyl estradiol: 2.5-3.5 L/kg; indicates extensive tissue distribution.
Levonorgestrel: Vd ~1.8 L/kg (suggesting extensive tissue distribution). Ethinyl estradiol: Vd ~2.4 L/kg.
Oral: norgestrel >90%; ethinyl estradiol 40-50% (first-pass metabolism).
Oral bioavailability: levonorgestrel ~100% (nearly complete); ethinyl estradiol ~45-50% (first-pass hepatic metabolism).
No dosage adjustment required for mild to moderate renal impairment. Use is contraindicated in severe renal impairment or acute renal failure due to potential fluid retention.
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 acute or chronic hepatic dysfunction, including Child-Pugh class A, B, or C. Do not use.
Contraindicated in severe hepatic dysfunction (Child-Pugh class B or C). Use caution in mild to moderate impairment (Child-Pugh A); monitor liver enzymes.
Not indicated for use before menarche. For postmenarchal adolescents, use same dosing as adults: one tablet daily for 21 days, then 7 days off.
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 postmenopausal women. No specific geriatric dosing; contraindicated in women over 35 who smoke, and generally avoided in older women due to increased cardiovascular risk.
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 (e.g., myocardial infarction, thromboembolism, stroke). Risk increases with age (>35 years) and smoking severity. Women over 35 who smoke should not use this drug.
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.
Thromboembolic disorders (venous and arterial),Cerebrovascular disease,Myocardial infarction,Hypertension,Hepatic adenoma or carcinoma,Gallbladder disease,Carbohydrate/lipid metabolism effects,Ocular changes (e.g., retinal thrombosis),Headache/migraine exacerbation,Uterine bleeding irregularities,Fetal development (discontinue if pregnancy suspected),Depression,Contact lens intolerance,Fluid retention,Breast cancer risk (ongoing surveillance),Hereditary angioedema
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.
Known or suspected pregnancy,Current or history of thrombophlebitis or thromboembolic disorders,Current or history of cerebrovascular or coronary artery disease,Breast cancer or other estrogen-sensitive neoplasia (known or suspected),Undiagnosed abnormal genital bleeding,Cholestatic jaundice of pregnancy or jaundice with prior pill use,Hepatic adenoma or carcinoma,Known liver impairment,Major surgery with prolonged immobilization,Diabetes mellitus with vascular involvement,Uncontrolled hypertension,Hypertriglyceridemia,Smoking >15 cigarettes/day and age ≥35,Migraine with focal aura at any age
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 exposure but does not require avoidance. Alcohol does not impair contraceptive efficacy but may increase risk of nausea or missed doses.
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. Fetal risk includes cardiovascular anomalies, neural tube defects, and limb reduction defects if exposed during first trimester. Second and third trimester exposure may cause masculinization of female fetuses due to progestin component.
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 norgestrel are excreted in human milk. M/P ratio not established. May reduce milk production and composition. Use is generally not recommended during breastfeeding; alternative contraception advised.
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 indicated as drug should not be used. Pharmacokinetic changes in pregnancy (e.g., increased clearance) are not relevant due to contraindication.
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.
LOW-OGESTREL-21 is a low-dose estrogen-progestin combination oral contraceptive. Its effectiveness may be reduced by concomitant enzyme-inducing drugs (e.g., rifampin, carbamazepine, phenytoin, St. John's wort). Breakthrough bleeding and spotting are more common with low-dose formulations. Contraception is not reliable if two or more active pills are missed; backup contraception is required. Initiation on the first day of menstrual bleeding eliminates need for backup contraception. Advise patients to take pill at same time daily to maintain consistent hormone levels.
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 daily at the same time, even if you have spotting or bleeding between periods.,If you miss one pill, take it as soon as you remember and continue the next pill at the usual time; no backup is needed.,If you miss two consecutive active pills, take two pills daily for two days, then resume one daily; use backup contraception for 7 days.,Possible side effects include nausea, headache, breast tenderness, and irregular bleeding; these often improve after 3 cycles.,Smoking while using this pill increases risk of serious cardiovascular events; do not smoke if over 35 years old.,Use a backup method (e.g., condoms) until you have taken 7 consecutive active pills if starting for the first time after day 5 of menstrual cycle.,Store pills at room temperature away from moisture.
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 LOW-OGESTREL-21 vs ALTAVERA, answered by our medical review team.
LOW-OGESTREL-21 is a Oral Contraceptive that works by Combination oral contraceptive. Suppresses gonadotropin release (FSH and LH) via estrogen (ethinyl estradiol) and progestin (norgestrel), inhibiting ovulation. Also increases cervical mucus viscosity and alters 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 LOW-OGESTREL-21 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 LOW-OGESTREL-21 is: One tablet (norgestrel 0.3 mg/ethinyl estradiol 30 mcg) orally once daily for 21 days, followed by 7 pill-free days.. 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 LOW-OGESTREL-21 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. LOW-OGESTREL-21 is classified as Category C. Pregnancy category X. Contraindicated in pregnancy. Fetal risk includes cardiovascular anomalies, neural tube defects, and limb reduction defects if exposed during first trimester.. 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.