Comparative Pharmacology
Head-to-head clinical analysis: NORINYL 1 80 21 DAY versus NORLESTRIN 21 2 5 50.
Peer-Reviewed Evidence
Head-to-head clinical analysis: NORINYL 1 80 21 DAY versus NORLESTRIN 21 2 5 50.
NORINYL 1+80 21-DAY vs NORLESTRIN 21 2.5/50
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Combination oral contraceptive containing norethindrone (a progestin) and ethinyl estradiol (an estrogen). Inhibits ovulation by suppressing gonadotropin release (FSH and LH). Also increases cervical mucus viscosity and alters endometrial morphology.
Combination oral contraceptive containing an estrogen (ethinyl estradiol) and a progestin (norethindrone acetate). Inhibits ovulation by suppressing gonadotropin release. Increases viscosity of cervical mucus, impeding sperm penetration, and alters endometrial receptivity.
One tablet orally once daily for 21 days, followed by 7 days of no active treatment.
One tablet orally once daily for 21 days, followed by 7 days off, then repeat.
None Documented
None Documented
Norethindrone: 8-11 hours; Mestranol: 12-24 hours (metabolized to ethinyl estradiol with half-life 20-27 hours). Steady-state after 5-7 days.
Norethindrone: 8 hours (terminal); Ethinyl estradiol: 13 hours (terminal). Clinical context: Steady-state achieved after 3-5 days; dosing interval based on once-daily administration.
Renal (40-60% as metabolites), fecal (20-30%)
Renal: 50-60% as metabolites (glucuronide and sulfate conjugates of norethindrone and ethinyl estradiol); fecal: 30-40% via biliary elimination; <1% unchanged.
Category C
Category C
Oral Contraceptive
Oral Contraceptive