Comparative Pharmacology
Head-to-head clinical analysis: KELNOR versus N E E 1 35 28.
Peer-Reviewed Evidence
Head-to-head clinical analysis: KELNOR versus N E E 1 35 28.
KELNOR vs N.E.E. 1/35 28
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Combined oral contraceptive; inhibits ovulation by suppressing gonadotropin release (FSH and LH) primarily via progestational activity; increases viscosity of cervical mucus to inhibit sperm penetration; alters endometrium.
Combination oral contraceptive; ethinyl estradiol and norethindrone suppress gonadotropin (FSH and LH) release, preventing ovulation. Also cause cervical mucus thickening and endometrial changes.
KELNOR (norethindrone acetate and ethinyl estradiol) is a combined oral contraceptive. Typical adult dose: 1 tablet (norethindrone acetate 1 mg/ethinyl estradiol 20 mcg) orally once daily for 21 days, followed by 7 placebo tablets, starting on day 1 of menstrual cycle.
One tablet orally once daily for 28 days; each tablet contains norethindrone 1 mg and ethinyl estradiol 35 mcg.
None Documented
None Documented
Terminal elimination half-life 12-15 hours; clinically relevant for once-daily dosing.
Ethinyl estradiol: ~15-19 hours (linear pharmacokinetics); Norethindrone: ~7-9 hours (terminal half-life; steady-state achieved within 5-7 days)
Primarily renal excretion of unchanged drug (70-80%) and glucuronide conjugate (10-15%); biliary/fecal elimination accounts for <5%.
Renal: ~50-60% (metabolites, primarily glucuronide conjugates); Fecal: ~30-40% (biliary excretion of metabolites); Unchanged drug: <5%
Category C
Category C
Oral Contraceptive
Oral Contraceptive