Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
OVCON-35 vs AFIRMELLE
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 contraceptive; suppresses gonadotropin release, inhibiting ovulation, and increases cervical mucus viscosity, impeding sperm penetration.
Combination oral contraceptive containing ethinyl estradiol and levonorgestrel. Inhibits ovulation by suppressing gonadotropin release (FSH and LH). Also increases cervical mucus viscosity and alters endometrial receptivity.
Prevention of pregnancy
Prevention of pregnancy (FDA-approved)
One tablet (35 mcg ethinyl estradiol and 0.4 mg norethindrone) orally once daily.
One tablet (0.1 mg levonorgestrel, 0.02 mg ethinyl estradiol) orally once daily for 21 days, followed by 7 days of placebo.
Ethinyl estradiol: 5-18 hours (mean ~12 hours, biphasic); norethindrone: 5-14 hours (mean ~8 hours). Terminal half-life relevant for once-daily dosing.
Terminal elimination half-life: 12–15 hours. Steady-state achieved within 5 days with Q12H dosing.
Ethinyl estradiol is primarily metabolized by CYP3A4; norethindrone is metabolized via reduction and sulfate conjugation, partly involving CYP3A4.
Ethinyl estradiol undergoes first-pass metabolism in gut and liver via CYP3A4, with conjugation to sulfate and glucuronide. Levonorgestrel is metabolized primarily by CYP3A4 to reduced and hydroxylated metabolites, then conjugated.
Renal 60% (metabolites, glucuronide conjugates), fecal 10%, biliary 5%, remainder via other pathways.
Renal: 50% as unchanged drug and metabolites; fecal: 40% as metabolites; biliary: ~10% as glucuronide conjugates.
Ethinyl estradiol: 97-98% (mainly albumin, SHBG); norethindrone: 90-95% (albumin, SHBG).
~99% bound to serum albumin and sex hormone-binding globulin.
Ethinyl estradiol: 2-4 L/kg; norethindrone: 4-6 L/kg. Large Vd indicates extensive tissue distribution.
2.8 L/kg (apparent Vd), indicating extensive tissue distribution.
Ethinyl estradiol: ~38-48% (first-pass metabolism); norethindrone: ~64% (range 47-73%).
Oral: ~70% due to first-pass metabolism.
No dose adjustment required for mild-to-moderate renal impairment. Contraindicated in severe renal impairment (GFR <30 m L/min) due to risk of hyperkalemia.
No dose adjustment required for mild to moderate renal impairment. Not recommended for use in end-stage renal disease.
Contraindicated in severe hepatic disease (Child-Pugh Class C) and active liver disease. Use with caution in Child-Pugh Class A or B; dose adjustment not established.
Contraindicated in acute hepatic disease or severe (Child-Pugh C) hepatic impairment. Use with caution in mild to moderate hepatic impairment; monitor liver function.
Safety and efficacy not established in children under 18 years. Postmenarchal adolescents: same as adult dosing, but weigh risks vs. benefits.
Not indicated for use before menarche. Post-menarche: same as adult dosing (one tablet daily) based on adult clinical trials.
Not typically used in postmenopausal women. Contraindicated in women over 60 due to increased risk of thromboembolic events and hypertension.
Not indicated for use in postmenopausal women; no specific dose adjustment required in healthy elderly, but limited data available.
Cigarette smoking increases risk of serious cardiovascular events from combination oral contraceptive use. This risk increases with age and with heavy smoking (≥15 cigarettes/day). Women over 35 who smoke should not use combination oral contraceptives.
Cigarette smoking increases risk of serious cardiovascular events from combination oral contraceptive use. Risk increases with age (especially in women over 35) and with heavy smoking (15+ cigarettes/day). Women who use combination hormonal contraceptives should be strongly advised not to smoke.
Increased risk of thromboembolic disorders, myocardial infarction, stroke, and hepatic neoplasia,Discontinue if jaundice, visual disturbances, or migraine headaches develop,May cause fluid retention; use with caution in conditions that might be aggravated by fluid retention,May decrease glucose tolerance; monitor diabetic patients,May cause elevation in blood pressure,Hereditary angioedema may be exacerbated
Thrombotic disorders (venous thromboembolism, stroke, myocardial infarction),Cigarette smoking (increases cardiovascular risk),Hypertension (especially in women with renal disease or migraines),Gallbladder disease,Hepatic neoplasia (benign and malignant),Carbohydrate and lipid metabolism effects,Ocular lesions (retinal thrombosis),Depressed mood or depression,Uterine bleeding irregularities,Reduced efficacy with hepatic enzyme inducers
Thrombophlebitis or thromboembolic disorders,Cerebrovascular or coronary artery disease,Known or suspected breast cancer,Estrogen-dependent neoplasia,Undiagnosed abnormal genital bleeding,Pregnancy,Active liver disease or benign/malignant liver tumors,Heavy smoking in women over 35
Thrombophlebitis or thromboembolic disorders (current or history),Cerebrovascular or coronary artery disease (current or history),Known or suspected breast cancer, endometrial cancer, or other estrogen-dependent neoplasia,Undiagnosed abnormal genital bleeding,Cholestatic jaundice of pregnancy or jaundice with prior oral contraceptive use,Hepatic adenoma or carcinoma (current or history),Known or suspected pregnancy,Hypersensitivity to any component of the product,Heavy smoking (≥15 cigarettes/day) in women over 35
No specific food interactions. However, grapefruit juice may increase ethinyl estradiol levels by inhibiting CYP3A4; avoid excessive consumption. Cranberry juice may increase warfarin effect if taken concurrently, but no direct interaction with OVCON-35. Take with food or milk to reduce nausea.
Grapefruit juice may increase ethinyl estradiol levels; avoid large quantities. No significant food restrictions. Administer with food if GI upset occurs.
FDA Pregnancy Category X. First trimester: increased risk of neural tube defects, congenital heart defects, and limb reduction defects. Second and third trimesters: fetal feminization in males, vaginal adenosis in females, and other urogenital anomalies. Postnatal: increased risk of neurodevelopmental issues.
Pregnancy category X. Contraindicated in pregnancy due to risk of fetal harm. First trimester: exposure associated with congenital anomalies (e.g., cardiovascular, neural tube defects). Second and third trimesters: increased risk of fetal growth restriction, preterm birth, and neonatal respiratory distress. Postnatal: possible long-term developmental effects.
Contraindicated in breastfeeding. Estrogens and progestins are excreted in breast milk. M/P ratio not established. May reduce milk production and quality.
Contraindicated during breastfeeding. Small amounts of ethinyl estradiol and norethindrone are excreted in breast milk; M/P ratio not well defined. Potential for adverse effects on infant (e.g., jaundice, breast enlargement). May reduce milk production and quality.
Contraindicated in pregnancy; no dose adjustment applies. Use is contraindicated once pregnancy is confirmed. Discontinue immediately.
Contraindicated in pregnancy; no dose adjustment recommended. If exposure occurs, immediate discontinuation is required. No pharmacokinetic data support safe use; avoid use entirely.
OVCON-35 is a combined oral contraceptive (COC) containing norethindrone 0.4 mg and ethinyl estradiol 35 mcg. It has higher progestin dose relative to estrogen, making it suitable for women with estrogen-related side effects. Monitor for breakthrough bleeding, particularly in early cycles. Contraindicated in women with BMI > 35 due to increased thromboembolic risk. Consider interaction with CYP450 inducers (e.g., rifampin) which may reduce contraceptive efficacy. Use with caution in migraine with aura due to stroke risk.
Afirmelle (levonorgestrel/ethinyl estradiol) is a combined oral contraceptive. Counsel patients to take at the same time daily to maintain consistent hormone levels. Use back-up contraception if a dose is missed. Monitor for signs of thromboembolism, especially in smokers over 35. Advise that certain antibiotics (e.g., rifampin) and anticonvulsants (e.g., phenytoin) may reduce efficacy. Consider progestin-only pill if contraindications to estrogen exist.
Take one tablet daily at the same time to maintain hormone levels and prevent pregnancy.,If you miss a pill, follow the instructions in the package insert or consult your healthcare provider. Missing pills increases pregnancy risk.,Common side effects include nausea, breast tenderness, headache, and breakthrough bleeding. These often improve after 2-3 cycles.,This medication does not protect against sexually transmitted infections (STIs). Use barrier protection.,Inform your doctor of all medications, especially antibiotics, anticonvulsants, or St. John's Wort, as they may reduce effectiveness.,Seek immediate medical attention if you experience severe leg pain, chest pain, sudden shortness of breath, or severe headache (signs of blood clots or stroke).,Do not smoke while using this medication, especially if over 35 years old; smoking increases risk of serious cardiovascular side effects.
Take one pill at the same time every day, even if you don't have sex.,If you miss a pill, follow the instructions in the package insert or ask your healthcare provider.,Use a backup method (like condoms) if you start late or miss pills.,This medication does not protect against HIV or other sexually transmitted infections.,Common side effects include nausea, breast tenderness, and breakthrough bleeding.,Seek medical help if you have symptoms of a blood clot: sudden chest pain, leg swelling, or shortness of breath.,Smoking while on this pill increases your risk of serious cardiovascular events.
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 OVCON-35 vs AFIRMELLE, answered by our medical review team.
OVCON-35 is a Oral Contraceptive that works by Combination estrogen-progestin contraceptive; suppresses gonadotropin release, inhibiting ovulation, and increases cervical mucus viscosity, impeding sperm penetration.. AFIRMELLE is a Combined Oral Contraceptive that works by Combination oral contraceptive containing ethinyl estradiol and levonorgestrel. Inhibits ovulation by suppressing gonadotropin release (FSH and LH). Also increases cervical mucus viscosity and alters endometrial receptivity.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between OVCON-35 and AFIRMELLE 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 OVCON-35 is: One tablet (35 mcg ethinyl estradiol and 0.4 mg norethindrone) orally once daily.. The standard adult dose of AFIRMELLE is: One tablet (0.1 mg levonorgestrel, 0.02 mg ethinyl estradiol) orally once daily for 21 days, followed by 7 days of placebo.. 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 OVCON-35 and AFIRMELLE 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. OVCON-35 is classified as Category C. FDA Pregnancy Category X. First trimester: increased risk of neural tube defects, congenital heart defects, and limb reduction defects. Second and third trimesters: fetal feminizat. AFIRMELLE is classified as Category C. Pregnancy category X. Contraindicated in pregnancy due to risk of fetal harm. First trimester: exposure associated with congenital anomalies (e.g., cardiovascular, neural tube defe. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.