Comparative Pharmacology
Head-to-head clinical analysis: LEVORA 0 15 30 21 versus NORQUEST FE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: LEVORA 0 15 30 21 versus NORQUEST FE.
LEVORA 0.15/30-21 vs NORQUEST FE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Combination oral contraceptive: ethinyl estradiol suppresses gonadotropin release via negative feedback on hypothalamic-pituitary axis; levonorgestrel inhibits ovulation and thickens cervical mucus, impairing sperm penetration. Also induces endometrial atrophy.
NORQUEST FE is a combination oral contraceptive containing ethinyl estradiol and norethindrone. Ethinyl estradiol suppresses gonadotropin release, inhibiting ovulation. Norethindrone induces progestational changes in the endometrium, increasing cervical mucus viscosity, and also inhibits ovulation.
One tablet orally once daily for 21 days, followed by 7 tablet-free days.
One tablet orally once daily, each tablet containing 1 mg norethindrone acetate and 20 mcg ethinyl estradiol (21 active tablets) followed by 7 ferrous fumarate tablets.
None Documented
None Documented
20-30 hours for ethinyl estradiol; 2-4 hours for levonorgestrel. Steady-state reached in 5-7 days
Terminal half-life: 6-8 hours. Clinical context: Supports once-daily dosing with sustained therapeutic effect.
Urine (50-60% as metabolites), feces (30-40% as glucuronides); <10% unchanged
Renal: 80% (50% unchanged, 30% as metabolites); Fecal: 19%; Biliary: <1%
Category C
Category C
Oral Contraceptive
Oral Contraceptive