Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
LEVLITE vs AFIRMELLE
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Levonorgestrel is a progestin that suppresses ovulation by inhibiting gonadotropin release (LH and FSH) and alters cervical mucus, endometrial thickness, and tubal motility.
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.
Emergency contraception,Contraception (as part of combination oral contraceptives or intrauterine system),Off-label: menstrual disorders, endometriosis
Prevention of pregnancy (FDA-approved)
One tablet (levonorgestrel 0.1 mg, ethinyl estradiol 0.02 mg) orally once daily for 21 days, followed by 7 placebo tablets.
One tablet (0.1 mg levonorgestrel, 0.02 mg ethinyl estradiol) orally once daily for 21 days, followed by 7 days of placebo.
Terminal elimination half-life: 21-28 hours; clinical context: permits once-daily dosing
Terminal elimination half-life: 12–15 hours. Steady-state achieved within 5 days with Q12H dosing.
Hepatic via CYP3A4; reduced to inactive metabolites; excreted in urine and feces.
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: ~50% (30% as unchanged drug, 20% as metabolites); Fecal: ~40%; Biliary: minor
Renal: 50% as unchanged drug and metabolites; fecal: 40% as metabolites; biliary: ~10% as glucuronide conjugates.
Levonorgestrel: ~99% bound to sex hormone-binding globulin (SHBG) and albumin; Ethinyl estradiol: ~98% bound to albumin
~99% bound to serum albumin and sex hormone-binding globulin.
Levonorgestrel: 1.8 L/kg; Ethinyl estradiol: 2.5 L/kg; clinical meaning: extensive tissue distribution
2.8 L/kg (apparent Vd), indicating extensive tissue distribution.
Oral: ~100% for both levonorgestrel and ethinyl estradiol (high bioavailability due to minimal first-pass metabolism)
Oral: ~70% due to first-pass metabolism.
No dose adjustment required for mild to moderate renal impairment. Not studied in severe renal impairment (GFR <30 m L/min); use with caution.
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). For mild to moderate impairment (Child-Pugh A/B), use with caution and monitor liver function.
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 in postmenarchal pediatric patients; safety and efficacy not established in prepubertal children.
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 studies available.
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. Women over 35 who smoke should not use combination hormonal 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.
Thrombotic disorders,Hepatic disease,Hypertension,Diabetes,Gallbladder disease,Depression,Ectopic pregnancy risk (emergency contraception),Reduced efficacy with CYP3A4 inducers
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,Undiagnosed abnormal genital bleeding,Severe hepatic disease,Known or suspected breast cancer,History of thromboembolic disorders,Hypersensitivity to levonorgestrel
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 known significant food interactions. Grapefruit and grapefruit juice do not interact with ethinyl estradiol or levonorgestrel. However, a high-fat meal may increase absorption of some oral contraceptives; consistency in taking with or without food is recommended.
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. Ethinyl estradiol and levonorgestrel are contraindicated in pregnancy due to risk of fetal harm, including cardiovascular defects and limb reduction defects from first-trimester exposure. Second and third trimester exposure may be associated with genitourinary abnormalities and masculinization of female fetuses.
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.
Excreted in breast milk in small amounts. Ethinyl estradiol concentration in milk ~0.02-0.1 ng/m L; levonorgestrel M/P ratio ~0.35-1.0. No adverse effects reported at typical doses. May reduce milk production; use caution in lactating women, especially with high doses.
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.
No dose adjustment applicable as use is contraindicated in pregnancy. Pharmacokinetic changes in pregnancy (increased clearance, decreased binding protein) are irrelevant due to contraindication.
Contraindicated in pregnancy; no dose adjustment recommended. If exposure occurs, immediate discontinuation is required. No pharmacokinetic data support safe use; avoid use entirely.
LEVLITE is a combination oral contraceptive containing ethinyl estradiol and levonorgestrel. Use with caution in women with migraines with aura due to increased stroke risk. Smoking increases cardiovascular risk, especially in women over 35. Monitor blood pressure at baseline and periodically. Consider alternative contraception in women with uncontrolled hypertension or history of venous thromboembolism.
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 pill daily at the same time each day.,If you miss a pill, follow the package instructions or consult your healthcare provider.,Do not smoke while taking this medication, as it increases the risk of blood clots and heart problems.,Use barrier contraception if you also take certain antibiotics or anticonvulsants.,Common side effects include nausea, headache, and breast tenderness, which often improve after a few months.,Seek immediate medical help for symptoms of a blood clot: leg pain/swelling, sudden chest pain, or trouble breathing.
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 LEVLITE vs AFIRMELLE, answered by our medical review team.
LEVLITE is a Oral Contraceptive that works by Levonorgestrel is a progestin that suppresses ovulation by inhibiting gonadotropin release (LH and FSH) and alters cervical mucus, endometrial thickness, and tubal motility.. 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 LEVLITE 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 LEVLITE is: One tablet (levonorgestrel 0.1 mg, ethinyl estradiol 0.02 mg) orally once daily for 21 days, followed by 7 placebo tablets.. 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 LEVLITE 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. LEVLITE is classified as Category C. FDA Pregnancy Category X. Ethinyl estradiol and levonorgestrel are contraindicated in pregnancy due to risk of fetal harm, including cardiovascular defects and limb reduction defec. 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.