Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
LARIN FE 1/20 vs DEMULEN 1/35-28
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
LARIN FE 1/20 is a combination oral contraceptive containing ethinyl estradiol and norethindrone. It inhibits ovulation by suppressing gonadotropin release (FSH and LH) from the pituitary, increases viscosity of cervical mucus, and alters endometrial receptivity.
Combination estrogen-progestin contraceptive; suppresses gonadotropin release, inhibiting ovulation; increases cervical mucus viscosity, impeding sperm penetration; alters endometrial receptivity.
Prevention of pregnancy in women who elect to use an oral contraceptive
Prevention of pregnancy
One tablet orally once daily for 21 consecutive days, followed by 7 days of placebo (ferrous fumarate) tablets per cycle.
One tablet (contains 1 mg ethynodiol diacetate and 35 mcg ethinyl estradiol) orally once daily at the same time each day for 21 days, followed by 7 days of placebo or no tablets.
Ethinyl estradiol: ~13 hours (range 7-20); norethindrone: ~8-11 hours. Steady-state reached in 5-7 days.
Ethinyl estradiol: 17.4 ± 5.6 h (terminal); norethindrone: 10.9 ± 1.6 h (terminal); clinically, steady-state achieved within 5-7 days.
Ethinyl estradiol is metabolized primarily via CYP3A4, with sulfation and glucuronidation. Norethindrone is reduced and conjugated, primarily via CYP3A4 and other CYP450 enzymes.
Ethinylestradiol undergoes hepatic metabolism via CYP3A4; norethindrone undergoes reduction and conjugation in the liver.
Renal (60% as metabolites, <10% unchanged); biliary/fecal (40%)
Renal 50% (metabolites), fecal 50% (biliary elimination of conjugates).
Ethinyl estradiol: 97-98% (albumin, SHBG); norethindrone: 80-85% (albumin, SHBG)
Ethinyl estradiol: 97-98% bound to albumin; norethindrone: 93% bound to albumin and SHBG.
Ethinyl estradiol: 2.5-5 L/kg; norethindrone: 2-4 L/kg. Indicates extensive tissue distribution.
Ethinyl estradiol: 2.3-4.3 L/kg; norethindrone: 4.4 L/kg; indicates extensive tissue distribution.
Oral: ~40% for ethinyl estradiol (first-pass metabolism); ~64% for norethindrone (range 50-75%)
Ethinyl estradiol: 40-45% (oral; first-pass metabolism); norethindrone: 64-67% (oral).
No dose adjustment required for mild to moderate renal impairment. Severe renal impairment (GFR <30 m L/min) may require monitoring due to potential fluid retention; use lowest effective dose.
No dose adjustment required for mild to moderate renal impairment. Contraindicated in severe renal impairment or acute renal failure.
Contraindicated in Child-Pugh class C cirrhosis. For Child-Pugh class B, use with caution and only if benefits outweigh risks; consider alternative methods of contraception. Child-Pugh class A: no adjustment necessary.
Contraindicated in acute or chronic hepatic dysfunction, including Child-Pugh class A, B, or C. Avoid use if liver function tests are abnormal.
Approved for post-menarcheal adolescents. Same dosing as adults: one active tablet daily for 21 days, then placebo for 7 days. Weight-based adjustments not required.
Not indicated for use before menarche. For postmenarchal adolescents, use same dosing as adults (one tablet orally once daily).
Not indicated for postmenopausal women. No specific geriatric dose adjustments, but consider increased risk of thrombotic events and manage cardiovascular risk factors.
Not indicated for use in postmenopausal women.
Cigarette smoking increases the risk of serious cardiovascular side effects from oral contraceptive use. The risk increases with age and with heavy smoking (≥15 cigarettes per day) and is quite marked in women >35 years of age. Women who use oral contraceptives should be strongly advised not to smoke.
Cigarette smoking increases risk of serious cardiovascular events. Risk increases with age and smoking intensity. Women over 35 who smoke should not use this product.
Thrombotic disorders: Risk of venous thromboembolism, arterial thrombosis, stroke, myocardial infarction.,Hepatic disease: Discontinue if jaundice or cholestasis develops.,Hypertension: Monitor blood pressure; may cause new-onset or worsening hypertension.,Gallbladder disease: Increased risk of gallstones.,Carbohydrate metabolism: May impair glucose tolerance.,Hypertriglyceridemia: May cause pancreatitis if elevated.,Uterine bleeding: Discontinue if unexplained amenorrhea or irregular bleeding persists.,Ocular disorders: Retinal thrombosis; discontinue if sudden partial or complete vision loss.,Depression: May recur or worsen.,Toxic shock syndrome: Associated with use of vaginal rings, but not specifically with this pill.
Increased risk of thromboembolic disorders,Cerebrovascular disease,Myocardial infarction,Hepatic neoplasia,Gallbladder disease,Hypertension,Carbohydrate/lipid effects,Headache,Uterine bleeding,Ocular lesions,Depression
Thrombophlebitis or thromboembolic disorders (current or history),Cerebrovascular or coronary artery disease (current or history),Known or suspected breast carcinoma,Endometrial carcinoma or other estrogen-dependent neoplasia,Undiagnosed abnormal genital bleeding,Pregnancy (known or suspected),Benign or malignant liver tumors (current or history),Active liver disease (e.g., acute hepatitis, decompensated cirrhosis),Hypersensitivity to any component of the product
Known or suspected pregnancy,Current or past thrombosis,Cerebrovascular or coronary artery disease,Valvular heart disease with complications,Severe hypertension,Diabetes with vascular involvement,Headaches with focal neurological symptoms,Major surgery with prolonged immobilization,Known or suspected breast cancer,Endometrial cancer or other estrogen-dependent neoplasia,Undiagnosed abnormal genital bleeding,Cholestatic jaundice of pregnancy or jaundice with prior pill use,Hepatic adenomas or carcinomas,Active liver disease,Known hypersensitivity to any component
No significant food interactions. However, grapefruit juice may slightly increase ethinyl estradiol levels; avoid large amounts. The ferrous fumarate in placebo pills may cause gastrointestinal upset; take with food if needed.
No significant food interactions. Grapefruit juice has minimal effect on ethinyl estradiol; no restriction needed. Avoid excessive alcohol, which may impair adherence or increase liver enzymes. St. John's wort reduces contraceptive efficacy and should be avoided.
Pregnancy category X. Use contraindicated in pregnancy due to known teratogenicity. First-trimester exposure associated with cardiovascular defects and limb reduction defects. Second and third trimesters: no increased risk of malformations but potential for adverse effects from progestational agents and estrogen. Risk of fetal genital abnormalities with prolonged exposure.
First trimester: Increased risk of neural tube defects, cardiovascular anomalies, and oral clefts (OR ~1.3-1.6). Second/third trimester: Androgenization of female fetus (clitoromegaly, labial fusion) due to progestin component; possible association with hypospadias in males with first-trimester exposure. Avoid use in pregnancy.
Contraindicated in breastfeeding. Small amounts of estrogen and progestin (norethindrone) pass into breast milk. M/P ratio: not established for this combination. May reduce milk production and quality. Use alternative contraception if breastfeeding.
Excreted in breast milk; estimated infant dose <1% of maternal dose. M/P ratio not available for ethinyl estradiol/ethynodiol diacetate. May reduce milk production and quality. Use only if benefits outweigh risks; lowest effective dose recommended.
Contraindicated in pregnancy; no dose adjustments recommended as use is prohibited. No pharmacokinetic studies during pregnancy due to contraindication.
Contraindicated in pregnancy; no dose adjustment applicable. If inadvertently used, discontinue immediately.
LARIN FE 1/20 is a combination oral contraceptive containing norethindrone acetate (1 mg) and ethinyl estradiol (20 mcg). It uses a 24/4 regimen with 24 active pills and 4 ferrous fumarate placebo pills. The iron supplements in the placebo pills help reduce the risk of iron deficiency anemia. Advise patients that spotting or breakthrough bleeding is common in the first few cycles. Monitor for hypertension, migraines, and thrombotic events. Smoking increases cardiovascular risk, especially in women over 35. LARIN FE 1/20 may decrease milk production in breastfeeding women.
DEMULEN 1/35-28 (ethinyl estradiol 35 mcg + ethynodiol diacetate 1 mg) is a monophasic combined oral contraceptive. Its progestin has mild androgenic activity, which may be less favorable for acne-prone patients compared to third-generation pills. The 28-day pack includes 21 active pills and 7 inert pills. Counsel patients to take at the same time daily; missed pills increase breakthrough bleeding and pregnancy risk. It may be used off-label for cycle control in patients without contraindications.
Take one pill daily at the same time each day. Swallow the pill whole; do not crush or chew.,Start the pack on the first Sunday after your period starts (unless instructed otherwise).,Use backup contraception (like condoms) for the first 7 days if you start taking the pill for the first time.,If you miss a pill, refer to the package insert for instructions. Missing pills increases pregnancy risk.,Common side effects include nausea, breast tenderness, and breakthrough bleeding. These often improve after a few months.,Contact your healthcare provider if you experience severe abdominal pain, chest pain, sudden shortness of breath, severe headaches, vision changes, or leg pain/swelling (possible blood clots).,Talk to your doctor before starting if you smoke, are over 35, have high blood pressure, migraines with aura, or a history of blood clots.,The iron pills (brown tablets) are not active birth control; they are taken during the fourth week to help prevent anemia.,Do not stop taking the pill without consulting your doctor.
Take one pill daily at the same time, preferably after dinner to reduce nausea.,If you miss one pill, take it as soon as remembered; if missed more than one, use backup contraception for 7 days.,Smoking increases risk of blood clots; especially dangerous if over 35 and smokes.,Some antibiotics (e.g., rifampin) and antiseizure medications may reduce effectiveness.,Report any signs of blood clot: sudden leg pain/swelling, chest pain, shortness of breath, or sudden severe headache.,Breakthrough bleeding is common in first 3 cycles; if persistent, contact your healthcare provider.,Do not use if pregnant; if pregnancy occurs, stop immediately.
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 LARIN FE 1/20 vs DEMULEN 1/35-28, answered by our medical review team.
LARIN FE 1/20 is a Combination Oral Contraceptive that works by LARIN FE 1/20 is a combination oral contraceptive containing ethinyl estradiol and norethindrone. It inhibits ovulation by suppressing gonadotropin release (FSH and LH) from the pituitary, increases viscosity of cervical mucus, and alters endometrial receptivity.. DEMULEN 1/35-28 is a Combination Oral Contraceptive that works by Combination estrogen-progestin contraceptive; suppresses gonadotropin release, inhibiting ovulation; increases cervical mucus viscosity, impeding sperm penetration; alters endometrial receptivity.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between LARIN FE 1/20 and DEMULEN 1/35-28 depend on the specific clinical indication. These are both Combination 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 LARIN FE 1/20 is: One tablet orally once daily for 21 consecutive days, followed by 7 days of placebo (ferrous fumarate) tablets per cycle.. The standard adult dose of DEMULEN 1/35-28 is: One tablet (contains 1 mg ethynodiol diacetate and 35 mcg ethinyl estradiol) orally once daily at the same time each day for 21 days, followed by 7 days of placebo or no tablets.. 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 LARIN FE 1/20 and DEMULEN 1/35-28 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. LARIN FE 1/20 is classified as Category C. Pregnancy category X. Use contraindicated in pregnancy due to known teratogenicity. First-trimester exposure associated with cardiovascular defects and limb reduction defects. Seco. DEMULEN 1/35-28 is classified as Category C. First trimester: Increased risk of neural tube defects, cardiovascular anomalies, and oral clefts (OR ~1.3-1.6). Second/third trimester: Androgenization of female fetus (clitoromeg. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.