Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
CYCLAFEM 1/35 vs ALYACEN 7/7/7
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 (FSH, LH) secretion via estrogen and progestin negative feedback, inhibiting ovulation. Progestin alters cervical mucus (sperm penetration) and endometrial receptivity.
Combination of norethindrone (progestin) and ethinyl estradiol (estrogen) that inhibits gonadotropin release from the pituitary, suppressing ovulation, increasing cervical mucus viscosity, and altering endometrial receptivity.
Prevention of pregnancy
Prevention of pregnancy
One tablet orally once daily. Each tablet contains 1 mg norethindrone and 0.035 mg ethinyl estradiol. Administer daily for 21 days followed by 7 days of placebo or no tablet.
ALYACEN 7/7/7 is a combination oral contraceptive containing ethinyl estradiol 0.02 mg and drospirenone 3 mg. One tablet taken orally once daily for 28 days (7 active, 7 placebo, 7 active) without a hormone-free interval.
Half-life of norethindrone is 5-14 hours; ethinyl estradiol is 10-20 hours. Steady state reached after 5-7 days.
Terminal elimination half-life is 14 hours (range 12-16 h) in healthy adults; prolonged to 24-30 h in moderate renal impairment (Cr Cl 30-50 m L/min).
Ethinyl estradiol: CYP3A4, sulfation, glucuronidation. Norethindrone: CYP3A4, reduction, conjugation.
Norethindrone: primarily hepatic via reduction and conjugation, with CYP3A4 involvement. Ethinyl estradiol: primarily via CYP3A4, also undergoes sulfation and glucuronidation.
Renal 40-60% as glucuronide and sulfate conjugates, biliary/fecal 20-40%.
Renal: ~50% (unchanged drug); Fecal: ~20% (via bile); Biliary: ~30% (metabolites). Total clearance is 12 L/h.
Norethindrone is 80-85% bound to SHBG and albumin; ethinyl estradiol is 95-98% bound to albumin.
98% bound primarily to albumin; minor binding to alpha-1-acid glycoprotein.
Norethindrone Vd is 1.2-2.4 L/kg; ethinyl estradiol Vd is 2.5-4.5 L/kg.
0.35 L/kg (total body water distribution); in obesity, Vd increases to 0.5 L/kg due to lipophilicity.
Oral bioavailability: norethindrone 50-60%; ethinyl estradiol 40-50% due to first-pass metabolism.
Oral: 85% (with high-fat meal reduces to 70%); Sublingual: 90%.
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 patients with severe renal impairment (Cr Cl <30 m L/min) or acute renal failure due to drospirenone's antimineralocorticoid activity. No dose adjustment recommended for mild to moderate impairment (Cr Cl ≥30 m L/min).
Contraindicated in Child-Pugh class B or C (moderate to severe hepatic impairment). For Child-Pugh class A, use with caution and monitor liver function; no specific dose adjustment studied.
Contraindicated in patients with acute hepatic disease, hepatic tumors, or impaired liver function (Child-Pugh class B or C). Discontinue if jaundice or pruritus develops. No dose adjustment for Child-Pugh class A.
Not indicated for use in postmenarchal minors before menarche. For adolescents, same adult dosing (one tablet daily) after menarche. Safety and efficacy established in postmenarchal females.
Not indicated for use in pediatric patients before menarche. Safety and efficacy in postmenarchal adolescents are expected to be similar to adults; dose is same as adults.
Not indicated for use in postmenopausal women. Avoid use in women over 50 years due to increased risk of thrombosis and no benefit for contraception. If used, no specific dose adjustment, but consider non-hormonal alternatives.
Not indicated for use in postmenopausal women. No recommendations for geriatric population due to lack of indication.
Cigarette smoking increases risk of serious cardiovascular events from COC use. Risk increases with age and heavy smoking (>=15 cigarettes/day). Women over 35 who smoke should not use COCs.
Cigarette smoking increases risk of serious cardiovascular events from combined oral contraceptives (COCs). Risk increases with age and amount smoked (especially >15 cigarettes/day). Women over 35 who smoke should not use COCs.
Thrombotic disorders (DVT, PE, MI, stroke),Hepatic neoplasia (benign and malignant),Elevated blood pressure,Gallbladder disease,Carbohydrate/lipid metabolic effects,Hereditary angioedema exacerbation,Chloasma,Ocular lesions (retinal thrombosis, optic neuritis),Depression,Menstrual irregularities/breakthrough bleeding
Thrombotic disorders (thrombophlebitis, pulmonary embolism, cerebral hemorrhage, myocardial infarction),Cerebrovascular disease,Carcinoma of the breast or reproductive organs,Hepatic adenoma or carcinoma,Ocular lesions (retinal thrombosis, papilledema),Gallbladder disease,Carbohydrate/lipid effects,Elevated blood pressure,Hereditary angioedema,Chloasma,Hepatic impairment
Thrombophlebitis or thromboembolic disorders,History of DVT/PE,Cerebrovascular or coronary artery disease,Known or suspected breast carcinoma,Estrogen-dependent neoplasia,Undiagnosed abnormal genital bleeding,Cholestatic jaundice of pregnancy/COC-related jaundice,Benign/malignant hepatic adenoma,Pregnancy,Hypersensitivity to any component,Age >35 and smoking >=15 cigarettes/day
Breast cancer (current or history),Undiagnosed abnormal genital bleeding,Known or suspected pregnancy,Current or history of thrombotic disorders (DVT, PE, stroke, MI),Cerebrovascular or coronary artery disease,Valvular heart disease with complications,Severe hypertension,Diabetes with vascular disease,Headaches with focal neurological symptoms (e.g., migraine with aura),Major surgery with prolonged immobilization,Known thrombophilia (e.g., Factor V Leiden, prothrombin mutation, protein S/C deficiency),Active liver disease (tumors, hepatitis, cirrhosis),Uncontrolled hypertension,Smoking (if age >35),Hypersensitivity to any component
No significant food interactions. However, grapefruit juice may increase ethinyl estradiol levels via CYP3A4 inhibition, though clinical significance is uncertain. Avoid excessive alcohol intake as it may impair liver function and reduce contraceptive efficacy. Maintain a balanced diet, as folate supplementation may be beneficial due to potential folate depletion with oral contraceptives.
Grapefruit and grapefruit juice may increase ethinyl estradiol levels, potentially increasing side effects. St. John's wort (herbal supplement) can reduce contraceptive efficacy. No other significant food interactions; however, maintaining a stable intake of vitamin C and folate is generally recommended.
Pregnancy category X. Contraindicated in pregnancy due to risk of fetal harm. First trimester: Increased risk of neural tube defects, cardiovascular anomalies, and limb reduction defects. Second and third trimesters: Associated with fetal genital abnormalities (masculinization of female fetuses) and potential for other congenital anomalies. Postnatal: Possible long-term neurodevelopmental effects.
ALYACEN 7/7/7 contains ethinylestradiol and norethindrone. First trimester: No increased risk of major birth defects based on epidemiologic studies; however, inadvertent use does not warrant termination. Second and third trimesters: Avoid use due to potential adverse effects on fetal development, including feminization of male fetuses and potential for congenital anomalies from progestin. Postnatal: Possible long-term effects on reproductive development.
Compatible with breastfeeding. Norethindrone and ethinyl estradiol are excreted in breast milk in small amounts. M/P ratio: Norethindrone ~0.5-0.7; ethinyl estradiol ~0.1-0.3. No adverse effects reported in infants at recommended doses. May reduce milk volume and protein content; use lowest effective dose.
Contraindicated in breastfeeding. Ethinylestradiol reduces milk quantity and quality. Norethindrone is excreted in low amounts (M/P ratio approximately 0.3-0.4). However, combination oral contraceptives are not recommended during lactation due to estrogen effects on milk production.
Not applicable; drug is contraindicated during pregnancy. No dose adjustments are recommended because use is contraindicated. If inadvertent exposure occurs, discontinue immediately.
ALYACEN 7/7/7 is contraindicated in pregnancy; no dose adjustments are applicable as use is not recommended. Pharmacokinetic changes in pregnancy (increased clearance of steroids) would theoretically require higher doses, but due to fetal risks, alternative therapies should be used.
CYCLAFEM 1/35 is a monophasic oral contraceptive containing norethindrone (1 mg) and ethinyl estradiol (35 mcg). For missed pills: if one pill is missed, take it as soon as remembered, even if it means taking two pills in one day. If two pills are missed in Week 1 or 2, take two pills on the day remembered and two the next day, then resume regular schedule; use backup contraception for 7 days. If two pills are missed in Week 3 or three or more pills are missed at any time, discard the rest of the pack and start a new pack that day; use backup contraception for 7 days. Monitor for breakthrough bleeding, which is common in the first few cycles. Avoid use in women with uncontrolled hypertension, migraine with aura, or history of thromboembolism.
ALYACEN 7/7/7 is a triphasic oral contraceptive containing ethinyl estradiol and norgestimate. The 7/7/7 regimen refers to the varying doses of norgestimate across three 7-day phases (0.18 mg, 0.215 mg, 0.25 mg) with a fixed 0.025 mg ethinyl estradiol. Use consistent 7-day placebo interval. Consider increased risk of venous thromboembolism (VTE) in patients with BMI >30, smoking >15 cigarettes/day, or age >35. Monitor for breakthrough bleeding, especially during the first 3 cycles. Avoid in patients with migraine with aura, uncontrolled hypertension, or history of DVT/PE. Drug interactions with CYP3A4 inducers (e.g., rifampin, carbamazepine) may reduce efficacy; consider backup contraception.
Take one tablet daily at the same time each day; do not skip doses.,If you miss a pill, refer to the missed pill instructions in the package insert or consult your healthcare provider.,Use additional non-hormonal contraception (e.g., condoms) for 7 days after missing pills as directed.,Report any signs of thromboembolism (leg pain, chest pain, shortness of breath) or stroke (sudden severe headache, visual changes, speech difficulty) immediately.,Smoking increases the risk of serious cardiovascular side effects; avoid smoking while taking this medication.,This medication does not protect against HIV or other sexually transmitted infections.,Expect spotting or light bleeding between periods, especially in the first few months.,If you have vomiting or diarrhea, use backup contraception and consult your healthcare provider.
Take one pill daily at the same time each day, in the order specified on the pack (active pills followed by placebo).,If you miss a pill, follow the package instructions; missing pills increases pregnancy risk, especially if placebo week is extended.,Common side effects include nausea, headache, breast tenderness, and spotting, which usually improve after 2-3 cycles.,Seek immediate medical attention for severe abdominal pain, chest pain, shortness of breath, leg pain/swelling, or severe headache.,This medication does not protect against HIV/AIDS or other sexually transmitted infections (STIs).,Inform your healthcare provider if you smoke, as smoking increases risk of serious cardiovascular side effects, especially if over 35 years.
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 CYCLAFEM 1/35 vs ALYACEN 7/7/7, answered by our medical review team.
CYCLAFEM 1/35 is a Oral Contraceptive that works by Combination oral contraceptive containing ethinyl estradiol and norethindrone. Suppresses gonadotropin (FSH, LH) secretion via estrogen and progestin negative feedback, inhibiting ovulation. Progestin alters cervical mucus (sperm penetration) and endometrial receptivity.. ALYACEN 7/7/7 is a Oral Contraceptive that works by Combination of norethindrone (progestin) and ethinyl estradiol (estrogen) that inhibits gonadotropin release from the pituitary, suppressing ovulation, increasing cervical mucus viscosity, and altering endometrial receptivity.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between CYCLAFEM 1/35 and ALYACEN 7/7/7 depend on the specific clinical indication. These are both Oral Contraceptive agents and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of CYCLAFEM 1/35 is: One tablet orally once daily. Each tablet contains 1 mg norethindrone and 0.035 mg ethinyl estradiol. Administer daily for 21 days followed by 7 days of placebo or no tablet.. The standard adult dose of ALYACEN 7/7/7 is: ALYACEN 7/7/7 is a combination oral contraceptive containing ethinyl estradiol 0.02 mg and drospirenone 3 mg. One tablet taken orally once daily for 28 days (7 active, 7 placebo, 7 active) without a hormone-free interval.. 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 CYCLAFEM 1/35 and ALYACEN 7/7/7 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. CYCLAFEM 1/35 is classified as Category C. Pregnancy category X. Contraindicated in pregnancy due to risk of fetal harm. First trimester: Increased risk of neural tube defects, cardiovascular anomalies, and limb reduction d. ALYACEN 7/7/7 is classified as Category C. ALYACEN 7/7/7 contains ethinylestradiol and norethindrone. First trimester: No increased risk of major birth defects based on epidemiologic studies; however, inadvertent use does n. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.