Comparative Pharmacology
Head-to-head clinical analysis: KELNOR versus ORTHO NOVUM 7 7 7 21.
Peer-Reviewed Evidence
Head-to-head clinical analysis: KELNOR versus ORTHO NOVUM 7 7 7 21.
KELNOR vs ORTHO-NOVUM 7/7/7-21
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.
Combined hormonal contraceptive; primarily suppresses ovulation via inhibition of gonadotropin release (LH and FSH) from the pituitary. Also induces changes in cervical mucus and endometrium.
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 21 days, followed by 7 days of no tablets. Each tablet contains norethindrone 0.5 mg/0.75 mg/1 mg and ethinyl estradiol 35 mcg, with biphasic or triphasic dosing per cycle.
None Documented
None Documented
Terminal elimination half-life 12-15 hours; clinically relevant for once-daily dosing.
Ethinyl estradiol: 13-27 hours; norethindrone: 8-14 hours; with multiple dosing, steady state after 5-7 days.
Primarily renal excretion of unchanged drug (70-80%) and glucuronide conjugate (10-15%); biliary/fecal elimination accounts for <5%.
Renal: <10% unchanged; biliary/fecal: ~50% as metabolites; extensive enterohepatic recirculation.
Category C
Category C
Oral Contraceptive
Oral Contraceptive