Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
KARIVA vs ESTARYLLA
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Combination of ethinyl estradiol (estrogen) and levonorgestrel (progestin) that inhibits gonadotropin release, suppressing ovulation, altering cervical mucus to impede sperm penetration, and changing endometrial receptivity.
Estarylla is a combination oral contraceptive containing ethinyl estradiol and norgestimate. It suppresses gonadotropin release (FSH and LH) via estrogen and progestin, inhibiting ovulation. Additionally, it increases cervical mucus viscosity and alters endometrial receptivity, impeding sperm penetration and implantation.
Prevention of pregnancy,Management of heavy menstrual bleeding (off-label),Treatment of acne (off-label),Treatment of dysmenorrhea (off-label),Endometriosis pain relief (off-label)
FDA-approved: Prevention of pregnancy in women who elect to use oral contraceptives as a method of contraception.,Off-label: Acne vulgaris (for norgestimate-containing pills), management of menstrual disorders (e.g., dysmenorrhea, abnormal uterine bleeding), hormone therapy for transgender women (non-standardized).,Note: Off-label uses are not FDA-approved for this specific formulation.
One tablet (0.15 mg levonorgestrel/0.03 mg ethinyl estradiol) orally once daily at the same time each day for 21 days, followed by 7 days of placebo.
One tablet (0.02 mg ethinyl estradiol and 0.15 mg desogestrel) orally once daily for 21 days, followed by 7 days of placebo. Hormone-free interval of 7 days.
Terminal elimination half-life is 4.5 hours; in renal impairment (Cr Cl <30 m L/min), half-life may extend to 8-10 hours, requiring dose adjustment.
Terminal elimination half-life of ethinyl estradiol is approximately 13-16 hours; clinical context: steady-state achieved within 5-7 days
Hepatic via CYP3A4 for both ethinyl estradiol and levonorgestrel; undergoes conjugation (glucuronidation and sulfation). Ethinyl estradiol also undergoes oxidative metabolism. Levonorgestrel is reduced and conjugated.
Ethinyl estradiol is primarily metabolized by CYP3A4, with conjugation to glucuronides and sulfates. Norgestimate is rapidly metabolized to its active metabolite, norelgestromin, and further to levonorgestrel; involvement of CYP2C19 and CYP3A4 in norgestimate metabolism is noted.
Approximately 55% renal (30% as unchanged drug, 25% as metabolites) and 45% fecal (via biliary elimination).
Renal: ~55% as metabolites, ~27% unchanged; Fecal: ~45% as metabolites
99% bound to albumin; minor binding to alpha-1-acid glycoprotein.
Ethinyl estradiol: 97-98% bound to albumin, with minor binding to sex hormone-binding globulin
0.27 L/kg (range 0.2-0.5 L/kg); distribution into total body water and highly perfused tissues.
Ethinyl estradiol: approximately 2.8 L/kg; indicates extensive tissue distribution
Oral: 85-90% (complete absorption; first-pass metabolism reduces systemic availability to ~75% in elderly).
Oral: approximately 55% due to first-pass metabolism; consistent in healthy females
No dose adjustment required for mild to moderate renal impairment. Not studied in severe renal impairment or end-stage renal disease; use with caution and monitor for adverse effects.
No dose adjustment required for mild to moderate renal impairment. Not recommended for use in severe renal impairment or end-stage renal disease due to lack of data.
Contraindicated in acute hepatic disease or severe hepatic impairment (Child-Pugh class B or C). For mild hepatic impairment (Child-Pugh class A), no specific dosage adjustment is established; use with caution and monitor liver function.
Contraindicated in Child-Pugh class B and C (moderate to severe hepatic impairment). Use with caution in Child-Pugh class A; dose adjustment not specifically defined, but alternative contraception recommended.
Not indicated for use before menarche. For postmenarchal adolescents, same dosing as adults (one tablet daily as per 21/7 regimen).
Approved for use in postmenarchal adolescents: same dosing as adults (one tablet daily for 21 days, then 7 days placebo). No weight-based dosing required.
Not indicated for use after menopause. No specific elderly considerations as the drug is not used in this population.
Not indicated in postmenopausal women. No specific geriatric dosing; contraindicated in women over 60 years due to increased thromboembolic risk.
Cigarette smoking increases risk of serious cardiovascular events from combination hormonal contraceptive use. Risk increases with age (>35 years) and with number of cigarettes smoked. Women over 35 who smoke should not use Kariva.
Cigarette smoking increases the risk of serious cardiovascular side effects from combination oral contraceptives. This risk increases with age (especially in women over 35 years of age) and with the number of cigarettes smoked. Women who use combination hormonal contraceptives should be strongly advised not to smoke.
Increased risk of thromboembolic disorders (e.g., DVT, PE, MI, stroke),Hepatic neoplasia (benign and malignant) reported,Elevated blood pressure,Gallbladder disease,Carbohydrate and lipid metabolism effects,Retinal thrombosis (discontinue if vision loss or proptosis occurs),Depression,Bleeding irregularities (breakthrough bleeding, amenorrhea),Liver function abnormalities (discontinue if jaundice develops),Chloasma (may persist)
Thrombotic disorders: Increased risk of venous thromboembolism (VTE) and arterial thromboembolism (e.g., MI, stroke). Discontinue if thrombotic event occurs.,Cardiovascular disease: Avoid in women with uncontrolled hypertension, diabetes with vascular involvement, or history of thromboembolic disease.,Cigarette smoking: Strongly advise cessation, especially in women over 35.,Liver disease: Discontinue if jaundice or cholestasis develops; contraindicated in acute viral hepatitis or severe cirrhosis.,Hormone-dependent malignancies: Increased risk of breast cancer (current use) and cervical cancer; avoid if known or suspected breast cancer.,Gallbladder disease: Increased risk of gallstones.,Carbohydrate and lipid metabolism: Monitor glucose and lipids in predisposed patients; may impair glucose tolerance and increase triglycerides.,Headache: Evaluate if new-onset or worsening migraine, especially with focal neurological symptoms.,Uterine bleeding: Rule out pregnancy if amenorrhea occurs; irregular bleeding may require evaluation.,Depression: Monitor for mood changes; discontinue if severe depression recurs.,Angioedema: Risk in women with hereditary angioedema.
Thrombophlebitis or thromboembolic disorders (current or history),Cerebrovascular or coronary artery disease,Known or suspected breast carcinoma,Endometrial carcinoma or other estrogen-dependent neoplasia,Undiagnosed abnormal genital bleeding,Pregnancy (known or suspected),Active liver disease or benign/malignant liver tumors,Severe hypertension,Diabetes with vascular involvement,Migraine with focal aura (especially if over 35 years),Hypersensitivity to any component,Use with Hepatitis C drug combinations containing ombitasvir/paritaprevir/ritonavir ± dasabuvir
Known or suspected pregnancy,Current or past venous thrombosis (e.g., deep vein thrombosis, pulmonary embolism),Current or past arterial thrombosis (e.g., myocardial infarction, stroke) or prodromal conditions (e.g., angina, transient ischemic attack),Known thrombophilic disorders (e.g., Factor V Leiden, prothrombin mutation, antithrombin deficiency),History of cerebrovascular or coronary artery disease,Uncontrolled hypertension (sustained >160/100 mm Hg),Diabetes mellitus with nephropathy, retinopathy, neuropathy, or other vascular disease,Headaches with focal neurological symptoms (e.g., migraine with aura) in women over 35,Current or past breast cancer, or other estrogen- or progestin-sensitive cancer,Active liver disease (e.g., acute viral hepatitis, severe cirrhosis) or benign/malignant liver tumors,Undiagnosed abnormal uterine bleeding,Hypersensitivity to any component of Estarylla,Use of highly active antiretroviral therapy (HAART) containing ritonavir or direct-acting antivirals for hepatitis C (e.g., ombitasvir/paritaprevir/ritonavir) due to potential for hepatotoxicity
No specific food interactions; however, grapefruit juice may increase estrogen levels (theoretical). Avoid high-fat meals as they may affect absorption. Consistent intake with food can reduce nausea.
There are no known significant food interactions. Grapefruit juice may increase estrogen levels but clinical significance is unclear; consider moderate intake.
FDA Pregnancy Category X. Contraindicated in pregnancy due to known teratogenicity. First trimester exposure associated with cardiovascular defects, limb reduction defects, and neural tube defects. Second and third trimester use linked to fetal hepatic adenoma and female pseudohermaphroditism (due to progestogenic activity).
Estarylla (ethinyl estradiol/levonorgestrel) is a combined oral contraceptive. Use during pregnancy is contraindicated. First trimester: No strong evidence of major malformations from inadvertent exposure, but increased risk of cardiovascular and limb defects in some studies. Second and third trimesters: Associated with fetal harm, including cardiovascular effects (e.g., congenital heart defects) and possible estrogenic effects, though data are limited. Postnatal effects: Potential long-term developmental effects unknown. Overall risk is low but not zero; avoid use in pregnancy.
Excreted into breast milk. M/P ratio not established. Avoid breastfeeding due to potential adverse effects in nursing infants.
Estarylla is excreted in breast milk in small amounts (ethinyl estradiol: M/P ratio ~0.2; levonorgestrel: M/P ratio ~0.3-0.4). Combined hormonal contraceptives may reduce milk production and affect milk composition, especially in early postpartum. Use is generally not recommended until breastfeeding is well-established (at least 6 weeks postpartum). For later use, progestin-only methods are preferred. Monitor infant for jaundice and growth.
Not applicable; contraindicated in pregnancy. No dose adjustment recommended for use in non-pregnant women.
Estarylla is contraindicated in pregnancy. No dosing adjustments are recommended because it should not be used. Pregnancy alters pharmacokinetics of oral contraceptives (e.g., increased volume of distribution, altered hepatic metabolism), but no dose changes are indicated due to contraindication. If inadvertently taken, discontinue immediately.
Kariva (desogestrel/ethinyl estradiol) is a monophasic oral contraceptive. It is effective for contraception but also used for acne and menstrual regulation. Breakthrough bleeding is common in first 3 cycles. Counsel on missed pill protocol. Check for contraindications: smoking >35, history of DVT/PE, migraine with aura, liver disease, breast cancer. Note that antibiotics (rifampin, griseofulvin) and anticonvulsants may reduce efficacy.
Estarylla is a combination oral contraceptive containing ethinyl estradiol and norgestimate. It is indicated for prevention of pregnancy. Monitor for thromboembolic events, especially in smokers over 35. Counsel on missed dose management: take as soon as remembered, use backup contraception if more than 24 hours late. May reduce menstrual cramps and acne. Not recommended in patients with history of estrogen-dependent neoplasia, liver disease, or uncontrolled hypertension.
Take one pill daily at the same time, preferably after an evening meal.,If you miss one pill, take it as soon as remembered; if missed two or more, use backup contraception.,Common side effects include nausea, breast tenderness, and spotting; these usually improve after 3 months.,Avoid smoking while taking this medication, especially if over 35 years old.,Inform your doctor before starting any new medications, including antibiotics and herbal supplements.,Kariva may decrease milk supply; not recommended if breastfeeding.
Take one pill daily at the same time each day.,If you miss a pill, take it as soon as remembered; use backup contraception if more than 24 hours late.,Do not smoke while taking this medication, especially if over 35.,Report any signs of blood clots: leg pain, chest pain, shortness of breath, or sudden vision changes.,This medication does not protect against HIV or other STDs.
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 KARIVA vs ESTARYLLA, answered by our medical review team.
KARIVA is a Combined Oral Contraceptive that works by Combination of ethinyl estradiol (estrogen) and levonorgestrel (progestin) that inhibits gonadotropin release, suppressing ovulation, altering cervical mucus to impede sperm penetration, and changing endometrial receptivity.. ESTARYLLA is a Combined Oral Contraceptive that works by Estarylla is a combination oral contraceptive containing ethinyl estradiol and norgestimate. It suppresses gonadotropin release (FSH and LH) via estrogen and progestin, inhibiting ovulation. Additionally, it increases cervical mucus viscosity and alters endometrial receptivity, impeding sperm penetration and implantation.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between KARIVA and ESTARYLLA depend on the specific clinical indication. These are both Combined 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 KARIVA is: One tablet (0.15 mg levonorgestrel/0.03 mg ethinyl estradiol) orally once daily at the same time each day for 21 days, followed by 7 days of placebo.. The standard adult dose of ESTARYLLA is: One tablet (0.02 mg ethinyl estradiol and 0.15 mg desogestrel) orally once daily for 21 days, followed by 7 days of placebo. Hormone-free interval of 7 days.. 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 KARIVA and ESTARYLLA 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. KARIVA is classified as Category C. FDA Pregnancy Category X. Contraindicated in pregnancy due to known teratogenicity. First trimester exposure associated with cardiovascular defects, limb reduction defects, and neu. ESTARYLLA is classified as Category C. Estarylla (ethinyl estradiol/levonorgestrel) is a combined oral contraceptive. Use during pregnancy is contraindicated. First trimester: No strong evidence of major malformations f. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.