Comparative Pharmacology
Head-to-head clinical analysis: KELNOR versus ORTHO NOVUM 7 14 21.
Peer-Reviewed Evidence
Head-to-head clinical analysis: KELNOR versus ORTHO NOVUM 7 14 21.
KELNOR vs ORTHO-NOVUM 7/14-21
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.
Combination estrogen-progestin contraceptive: suppresses gonadotropin release, inhibits ovulation, thickens cervical mucus, alters endometrial receptivity.
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 containing 0.5 mg norethindrone/0.035 mg ethinyl estradiol (white tablets) on days 1-14, then one tablet containing 1 mg norethindrone/0.035 mg ethinyl estradiol (peach tablets) on days 15-21, then no tablets for 7 days; repeated cycles.
None Documented
None Documented
Terminal elimination half-life 12-15 hours; clinically relevant for once-daily dosing.
Norethindrone: 10-12 hours (terminal), ethinyl estradiol: 13-27 hours (terminal); clinical context: 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: ~40% as glucuronide and sulfate conjugates; Fecal: ~20%; Biliary: minor
Category C
Category C
Oral Contraceptive
Oral Contraceptive