Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
LARIN 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
Combination estrogen-progestin contraceptive; suppresses gonadotropins (FSH, LH) via negative feedback on hypothalamic-pituitary axis, inhibiting ovulation; increases cervical mucus viscosity, inhibiting sperm penetration; 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,Oral contraceptive
Prevention of pregnancy
One tablet (0.1 mg levonorgestrel/20 mcg ethinyl estradiol) orally once daily for 21 days followed by 7 placebo days.
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.
Norethindrone: 7.6 hours (range 5-14); Ethinyl estradiol: 13.2 hours (range 8-20). Clinical context: Steady-state achieved within 5-10 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: primarily metabolized by CYP3A4; undergoes first-pass metabolism in gut and liver. Norethindrone: primarily metabolized by reduction and conjugation; substrate of CYP3A4.
Ethinylestradiol undergoes hepatic metabolism via CYP3A4; norethindrone undergoes reduction and conjugation in the liver.
Approximately 60% renal (30% norethindrone, 30% ethinyl estradiol metabolites) and 40% fecal (biliary excretion of conjugates).
Renal 50% (metabolites), fecal 50% (biliary elimination of conjugates).
Norethindrone: 61% (albumin, SHBG); Ethinyl estradiol: 97% (albumin).
Ethinyl estradiol: 97-98% bound to albumin; norethindrone: 93% bound to albumin and SHBG.
Norethindrone: 3.8 L/kg; Ethinyl estradiol: 2.8 L/kg. Indicates extensive tissue distribution.
Ethinyl estradiol: 2.3-4.3 L/kg; norethindrone: 4.4 L/kg; indicates extensive tissue distribution.
Oral: Norethindrone 64% (first-pass metabolism); Ethinyl estradiol 38-48% (first-pass metabolism).
Ethinyl estradiol: 40-45% (oral; first-pass metabolism); norethindrone: 64-67% (oral).
No dose adjustment required for mild to moderate renal impairment. Contraindicated in severe renal impairment (GFR <30 m L/min) due to potential fluid retention and metabolic acidosis.
No dose adjustment required for mild to moderate renal impairment. Contraindicated in severe renal impairment or acute renal failure.
Contraindicated in acute hepatic disease, hepatic adenomas, or severe cirrhosis (Child-Pugh class C). No specific dose adjustments provided for mild to moderate impairment; use caution.
Contraindicated in acute or chronic hepatic dysfunction, including Child-Pugh class A, B, or C. Avoid use if liver function tests are abnormal.
Not indicated for use before menarche. For postmenarchal adolescents, same dosing as adults: one tablet orally once daily for 21 days followed by 7 placebo days.
Not indicated for use before menarche. For postmenarchal adolescents, use same dosing as adults (one tablet orally once daily).
Not indicated for use after menopause. No specific dose adjustments in elderly; increased risk of thrombosis and hypoglycemia warrants caution.
Not indicated for use in postmenopausal women.
Cigarette smoking increases risk of serious cardiovascular events from combination oral contraceptives. Risk increases with age (especially >35 years) and with heavy smoking (≥15 cigarettes/day). Women who use combination hormonal contraceptives should not 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: discontinue if thrombophlebitis, thromboembolic, or vascular events occur,Carcinoma risk: increased risk of breast cancer; cervical cancer association,Hepatic effects: acute liver disease, liver tumors,Elevated blood pressure,Gallbladder disease,Carbohydrate/lipid metabolic effects,Ocular lesions: retinal thrombosis; discontinue if unexplained vision loss,Hereditary angioedema exacerbation,Chloasma,Pregnancy: discontinue if pregnancy occurs
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,History of deep vein thrombosis or pulmonary embolism,Cerebrovascular or coronary artery disease,Known or suspected breast cancer,Endometrial or other estrogen-dependent neoplasia,Undiagnosed abnormal genital bleeding,Cholestatic jaundice of pregnancy or jaundice with prior pill use,Hepatic adenoma or carcinoma,Known or suspected pregnancy,Hypersensitivity to any component,Heavy smoking (≥15 cigarettes/day) in women >35 years
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
Grapefruit and grapefruit juice may increase estrogen levels; limit intake. No other significant food interactions. Avoid St. John's wort (herbal supplement) as it reduces contraceptive efficacy. Alcohol may increase risk of liver toxicity; moderate consumption is generally acceptable.
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.
LARIN 1/20 (norethindrone acetate/ethinyl estradiol) is contraindicated in pregnancy. First trimester: No increased risk of major birth defects from low-dose OCs in cohort studies, but an increased risk of cardiovascular malformations (e.g., VSD, TGA) and neural tube defects has been suggested in some studies; risk of oral cleft is not increased. Second/third trimesters: Use may increase risk of fetal hepatic adenoma, fetal feminization with androgenic progestins (norethindrone has minimal androgenicity), and potential for neonatal withdrawal bleeding or hormonal effects; no clear risk of pregnancy loss beyond baseline.
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.
Small amounts of ethinyl estradiol and norethindrone pass into breast milk; combined OCs are generally not recommended during breastfeeding, especially in early lactation, as they may reduce milk quantity and quality. M/P ratio: Not established for LARIN 1/20; ethinyl estradiol M/P ratio is ~0.2-0.4, norethindrone M/P ratio ~0.1. Infants exposed via milk show no significant adverse effects, but theoretical risks include jaundice, breast enlargement, and long-term carcinogenicity. Use of progestin-only contraceptives is preferred.
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.
LARIN 1/20 is contraindicated in pregnancy; no dose adjustment recommended because drug should be discontinued immediately if pregnancy is detected. Pharmacokinetic changes in pregnancy (e.g., increased clearance, decreased SHBG, increased volume of distribution) would theoretically require higher doses if used, but use is not indicated. No standard dosing for use during gestation.
Contraindicated in pregnancy; no dose adjustment applicable. If inadvertently used, discontinue immediately.
LARIN 1/20 (norethindrone acetate 1 mg/ethinyl estradiol 20 mcg) has a low estrogen dose, which may reduce estrogen-related side effects but can increase breakthrough bleeding. It is a monophasic pill. Starting on the first day of menses provides immediate contraceptive protection. Caution in patients with migraine with aura or uncontrolled hypertension. Check for drug interactions with CYP3A4 inducers (e.g., rifampin, St. John's wort).
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; missing pills increases pregnancy risk.,If you miss a pill, follow the package instructions; use backup contraception if needed.,Common side effects include nausea, breast tenderness, and breakthrough bleeding, especially in the first few months.,Do not smoke while taking this medication, especially if over 35; smoking increases risk of serious cardiovascular events.,This pill does not protect against STIs; use condoms for protection.,Inform your healthcare provider of all medications and supplements you take, especially St. John's wort, antibiotics, and anticonvulsants.,Contact your doctor if you experience severe headache, chest pain, leg pain or swelling, sudden shortness of breath, or vision changes.
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 1/20 vs DEMULEN 1/35-28, answered by our medical review team.
LARIN 1/20 is a Combination Oral Contraceptive that works by Combination estrogen-progestin contraceptive; suppresses gonadotropins (FSH, LH) via negative feedback on hypothalamic-pituitary axis, inhibiting ovulation; increases cervical mucus viscosity, inhibiting sperm penetration; 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 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 1/20 is: One tablet (0.1 mg levonorgestrel/20 mcg ethinyl estradiol) orally once daily for 21 days followed by 7 placebo days.. 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 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 1/20 is classified as Category C. LARIN 1/20 (norethindrone acetate/ethinyl estradiol) is contraindicated in pregnancy. First trimester: No increased risk of major birth defects from low-dose OCs in cohort studies,. 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.