Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
ORTHO-NOVUM 7/14-28 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 oral contraceptive containing ethinyl estradiol and norethindrone. Suppresses gonadotropin release (FSH, LH) via negative feedback, inhibiting ovulation. Also increases cervical mucus viscosity and alters endometrial receptivity.
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 women ≥15 years of age who have no known contraindications and have achieved menarche,Off-label: menstrual cycle regulation, dysmenorrhea, endometriosis-associated pain
Prevention of pregnancy (FDA-approved)
One tablet daily for 28 days; each tablet contains norethindrone 0.5 mg and ethinyl estradiol 0.035 mg (days 1-7), norethindrone 0.75 mg and ethinyl estradiol 0.035 mg (days 8-14), norethindrone 1 mg and ethinyl estradiol 0.035 mg (days 15-21), and placebo (days 22-28). Take at same time each day.
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: ~13-27 h (mean 17 h); Norethindrone: ~5-14 h (mean 8 h). Clinical context: steady-state achieved after ~5 days; half-life supports daily dosing.
Terminal elimination half-life: 12–15 hours. Steady-state achieved within 5 days with Q12H dosing.
Ethinyl estradiol: primarily metabolized via CYP3A4, undergoes first-pass metabolism and enterohepatic circulation. Norethindrone: reduced to metabolites, conjugated (glucuronidation and sulfation), and 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: ~50-60% (metabolites); biliary/fecal: ~30-40% (metabolites); unchanged drug <1% in urine.
Renal: 50% as unchanged drug and metabolites; fecal: 40% as metabolites; biliary: ~10% as glucuronide conjugates.
Ethinyl estradiol: 97-98% bound to serum albumin; Norethindrone: 97-99% bound to albumin (major) and SHBG (minor).
~99% bound to serum albumin and sex hormone-binding globulin.
Ethinyl estradiol: 2.3-4.2 L/kg (mean 3.5 L/kg); Norethindrone: 2.5-5.0 L/kg (mean 3.8 L/kg). Clinical meaning: extensive distribution into tissues, including reproductive organs.
2.8 L/kg (apparent Vd), indicating extensive tissue distribution.
Oral: Ethinyl estradiol ~40-48% (first-pass metabolism); Norethindrone ~50-70% (first-pass metabolism). Food may slightly increase bioavailability.
Oral: ~70% due to first-pass metabolism.
No specific dose adjustment recommended in published literature; however, use with caution in patients with severe renal impairment (e GFR <30 m L/min) due to potential fluid retention and electrolyte disturbances. No data for specific GFR-based modifications.
No dose adjustment required for mild to moderate renal impairment. Not recommended for use in end-stage renal disease.
Contraindicated in patients with severe hepatic disease (Child-Pugh class C) or hepatic tumors. For Child-Pugh class A or B, use with caution; no specific dose adjustment guidelines exist. Discontinue if jaundice or signs of hepatic dysfunction develop.
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 post-menarcheal adolescents, same dosing as adults: one tablet daily for 28 days. Use only after appropriate evaluation and counseling.
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. Elderly-specific dosing not applicable.
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 this product.
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 (DVT, PE, stroke, MI),Cigarette smoking increases cardiovascular risk,Increased risk of cervical cancer (HPV-related),Hepatic neoplasia (benign/malignant) associated with long-term use,Exacerbation of migraine,Depression,Gallbladder disease,Impaired glucose tolerance,Elevated blood pressure,Hereditary angioedema
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 thromboembolic disorders (e.g., DVT, PE),Cerebrovascular or coronary artery disease,Known or suspected breast cancer,Active liver disease or benign/malignant liver tumors,Undiagnosed abnormal genital bleeding,Hypersensitivity to any component,Age >35 and smoking cigarettes,Uncontrolled hypertension,Diabetes with vascular involvement,Migraine with focal aura at any age,Major surgery with prolonged immobilization
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
Grapefruit juice may increase ethinyl estradiol levels and risk of adverse effects; consider avoiding. No other significant food interactions.
Grapefruit juice may increase ethinyl estradiol levels; avoid large quantities. No significant food restrictions. Administer with food if GI upset occurs.
First trimester: Post-marketing studies have not shown an increased risk of birth defects with combined oral contraceptives. However, inadvertent use during early pregnancy is not associated with teratogenicity. Second and third trimesters: Use is contraindicated due to potential adverse effects on fetal development, including estrogenic effects on female fetuses and androgenic effects on male fetuses. There is a risk of fetal genital abnormalities if exposed in utero, though absolute risk is low. Overall, category X designation for use during pregnancy.
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.
Combined oral contraceptives, including Ortho-Novum, are generally not recommended during breastfeeding, especially in the early postpartum period, due to estrogen-induced reduction in milk production and quality. Small amounts of ethinylestradiol and norethindrone are excreted in breast milk. M/P ratio for ethinylestradiol is approximately 0.15–0.3; for norethindrone, approximately 0.5–1.2. Progestin-only methods are preferred. Use only when no alternative and with caution.
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.
Ortho-Novum is contraindicated in pregnancy. No dose adjustments are recommended because use during pregnancy is not indicated. Pharmacokinetic changes in pregnancy (e.g., increased volume of distribution, altered hepatic metabolism) would theoretically require dose modifications, but since the drug is contraindicated, no adjustment is applicable.
Contraindicated in pregnancy; no dose adjustment recommended. If exposure occurs, immediate discontinuation is required. No pharmacokinetic data support safe use; avoid use entirely.
ORTHO-NOVUM 7/14-28 is a triphasic oral contraceptive with variable doses of norethindrone and ethinyl estradiol. Bleeding irregularities are common, especially in the first few cycles; reassure patients if pregnancy is ruled out. Missed pills increase risk of breakthrough ovulation; refer to package instructions for missed doses. Concomitant use of CYP3A4 inducers (e.g., rifampin, certain anticonvulsants) may reduce contraceptive efficacy.
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, starting on the first Sunday after your period begins.,Use backup contraception (e.g., condoms) for the first 7 days of the first cycle.,If you miss a pill, follow the specific instructions in the package insert based on how many you missed and the week of the cycle.,Common side effects include nausea, breast tenderness, and spotting; these often improve after 2-3 cycles.,Smoking increases the risk of serious cardiovascular side effects, especially if you are over 35 years old.,This medication does not protect against HIV or other sexually transmitted infections.
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 ORTHO-NOVUM 7/14-28 vs AFIRMELLE, answered by our medical review team.
ORTHO-NOVUM 7/14-28 is a Oral Contraceptive that works by Combination oral contraceptive containing ethinyl estradiol and norethindrone. Suppresses gonadotropin release (FSH, LH) via negative feedback, inhibiting ovulation. Also increases cervical mucus viscosity and alters endometrial receptivity.. 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 ORTHO-NOVUM 7/14-28 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 ORTHO-NOVUM 7/14-28 is: One tablet daily for 28 days; each tablet contains norethindrone 0.5 mg and ethinyl estradiol 0.035 mg (days 1-7), norethindrone 0.75 mg and ethinyl estradiol 0.035 mg (days 8-14), norethindrone 1 mg and ethinyl estradiol 0.035 mg (days 15-21), and placebo (days 22-28). Take at same time each day.. 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 ORTHO-NOVUM 7/14-28 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. ORTHO-NOVUM 7/14-28 is classified as Category C. First trimester: Post-marketing studies have not shown an increased risk of birth defects with combined oral contraceptives. However, inadvertent use during early pregnancy is not . 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.