Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
OVRAL vs AFIRMELLE
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
OVRAL is a combination oral contraceptive containing ethinyl estradiol and norgestrel. It inhibits ovulation by suppressing gonadotropin-releasing hormone (Gn RH) secretion from the hypothalamus, reducing follicle-stimulating hormone (FSH) and luteinizing hormone (LH) release from the pituitary. Additionally, it increases cervical mucus viscosity and alters endometrial receptivity, impeding sperm penetration and implantation.
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,Treatment of moderate acne vulgaris in females at least 15 years of age who have achieved menarche and are unresponsive to topical therapies
Prevention of pregnancy (FDA-approved)
One tablet (norgestrel 0.3 mg with ethinyl estradiol 0.03 mg) orally once daily for 21 days followed by 7 days of placebo.
One tablet (0.1 mg levonorgestrel, 0.02 mg ethinyl estradiol) orally once daily for 21 days, followed by 7 days of placebo.
Norgestrel: 24–32 hours; Ethinyl estradiol: 12–18 hours; steady-state achieved after 5–7 days
Terminal elimination half-life: 12–15 hours. Steady-state achieved within 5 days with Q12H dosing.
Ethinyl estradiol is primarily metabolized by CYP3A4, with sulfation and glucuronidation pathways. Norgestrel is hydroxylated via CYP3A4 and undergoes reduction and conjugation.
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% as metabolites, ~40% unchanged); biliary/fecal (40%)
Renal: 50% as unchanged drug and metabolites; fecal: 40% as metabolites; biliary: ~10% as glucuronide conjugates.
Norgestrel: 93–97% bound to SHBG; Ethinyl estradiol: 97–98% bound to albumin and SHBG
~99% bound to serum albumin and sex hormone-binding globulin.
Norgestrel: 1.5–2.5 L/kg; Ethinyl estradiol: 2.5–4.0 L/kg; extensive tissue distribution
2.8 L/kg (apparent Vd), indicating extensive tissue distribution.
Norgestrel: ~90%; Ethinyl estradiol: ~45–50% due to first-pass metabolism
Oral: ~70% due to first-pass metabolism.
No specific dose adjustment is required for mild to moderate renal impairment. Use with caution in severe renal impairment or end-stage renal disease due to potential for hormonal accumulation and adverse effects.
No dose adjustment required for mild to moderate renal impairment. Not recommended for use in end-stage renal disease.
Contraindicated in patients with acute or chronic hepatic disease or history of hepatic tumors (benign or malignant). In Child-Pugh class A (mild impairment), use with caution; in Child-Pugh class B or C (moderate to severe impairment), contraindicated.
Contraindicated in acute hepatic disease or severe (Child-Pugh C) hepatic impairment. Use with caution in mild to moderate hepatic impairment; monitor liver function.
Not indicated for use before menarche. For postmenarchal adolescents, same dosing as adults: one tablet orally daily for 21 days followed by 7 days of placebo.
Not indicated for use before menarche. Post-menarche: same as adult dosing (one tablet daily) based on adult clinical trials.
Not indicated for use in postmenopausal women. No specific geriatric dosing adjustments; consider increased risk of thrombosis and cardiovascular events in older women of reproductive age.
Not indicated for use in postmenopausal women; no specific dose adjustment required in healthy elderly, but limited data available.
Cigarette smoking increases the risk of serious cardiovascular events from combination oral contraceptive use. This risk increases with age and with the number of cigarettes smoked, and is particularly marked in women over 35 years of age. Women who use combination oral contraceptives should be strongly advised not to smoke.
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.
Thrombotic disorders: venous thromboembolism, arterial thromboembolism, stroke, myocardial infarction,Hepatic neoplasia: liver tumors (benign and malignant),Cervical cancer: increased risk with long-term use,Hypertension,Gallbladder disease,Carbohydrate and lipid metabolic effects,Headache (including migraine),Bleeding irregularities (breakthrough bleeding, spotting, amenorrhea),Depression,Ocular lesions (e.g., retinal thrombosis),Contact lens intolerance
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
Known or suspected pregnancy,Current or past history of thrombophlebitis or thromboembolic disorders,Cerebrovascular or coronary artery disease,Known or suspected breast cancer or other estrogen-sensitive neoplasia,Undiagnosed abnormal genital bleeding,Cholestatic jaundice of pregnancy or jaundice with prior pill use,Hepatic adenoma or carcinoma,Major surgery with prolonged immobilization,Heavy smoking (≥15 cigarettes/day) in women over 35 years of age,Known hypertriglyceridemia,Hypersensitivity to any component
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
Avoid grapefruit juice as it may increase estrogen levels and side effect risk. St. John's wort (herbal supplement) reduces contraceptive efficacy by inducing CYP3A4. No specific food restrictions; maintain consistent intake to minimize GI upset.
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: Known teratogen; associated with cardiovascular defects, neural tube defects, and limb reduction defects. Second trimester: Risk of fetal masculinization with progestins. Third trimester: Potential for feminization of male fetuses and virilization of female fetuses; increased risk of fetal adrenal suppression.
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 during breastfeeding. M/P ratio not established. Estrogens and progestins are excreted in human milk and may reduce milk production and quality. Potential adverse effects on infant include jaundice, breast enlargement, and hormonal disruption.
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 adjustments applicable as use is contraindicated.
Contraindicated in pregnancy; no dose adjustment recommended. If exposure occurs, immediate discontinuation is required. No pharmacokinetic data support safe use; avoid use entirely.
Ovral (norgestrel/ethinyl estradiol) is a combined oral contraceptive with high progestin potency, increasing the risk of venous thromboembolism. Consider for patients needing reliable contraception but avoid in those with migraine with aura, history of thromboembolic disorders, or liver disease. Breakthrough bleeding is common; manage by adjusting pill schedule or switching to a higher estrogen dose. Drug interactions with cytochrome P-450 inducers (e.g., rifampin, anticonvulsants) may reduce efficacy; consider backup contraception.
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 at the same time daily; missed pills require backup contraception.,Common side effects include nausea, headache, and breast tenderness; these often improve after a few cycles.,Report symptoms of thromboembolism (leg pain/swelling, sudden chest pain or dyspnea) or stroke (severe headache, vision changes).,Do not smoke while on Ovral; smoking increases risk of serious cardiovascular side effects, especially if over 35 years old.,Antibiotics (except rifampin) do not reduce efficacy; but certain anticonvulsants and St. John's wort do; use backup method with these.
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 OVRAL vs AFIRMELLE, answered by our medical review team.
OVRAL is a Oral Contraceptive that works by OVRAL is a combination oral contraceptive containing ethinyl estradiol and norgestrel. It inhibits ovulation by suppressing gonadotropin-releasing hormone (Gn RH) secretion from the hypothalamus, reducing follicle-stimulating hormone (FSH) and luteinizing hormone (LH) release from the pituitary. Additionally, it increases cervical mucus viscosity and alters endometrial receptivity, impeding sperm penetration and implantation.. 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 OVRAL 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 OVRAL is: One tablet (norgestrel 0.3 mg with ethinyl estradiol 0.03 mg) orally once daily for 21 days followed by 7 days of placebo.. 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 OVRAL 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. OVRAL is classified as Category C. FDA Pregnancy Category X. First trimester: Known teratogen; associated with cardiovascular defects, neural tube defects, and limb reduction defects. Second trimester: Risk of fetal. 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.