Comparative Pharmacology
Head-to-head clinical analysis: ENOVID E versus KELNOR.
Peer-Reviewed Evidence
Head-to-head clinical analysis: ENOVID E versus KELNOR.
ENOVID-E vs KELNOR
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Combination estrogen-progestin contraceptive. Suppresses gonadotropin release, inhibits ovulation, increases cervical mucus viscosity, and alters endometrial morphology.
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.
5 mg orally once daily for 20 days starting on day 5 of menstrual cycle
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.
None Documented
None Documented
Norethynodrel: 5-10 hours; mestranol: 2-5 hours (metabolized to ethinyl estradiol, half-life 10-20 hours). Steady-state reached in 5-7 days.
Terminal elimination half-life 12-15 hours; clinically relevant for once-daily dosing.
Renal (50-60% as metabolites, <1% unchanged); fecal (40-50%)
Primarily renal excretion of unchanged drug (70-80%) and glucuronide conjugate (10-15%); biliary/fecal elimination accounts for <5%.
Category C
Category C
Oral Contraceptive
Oral Contraceptive