Comparative Pharmacology
Head-to-head clinical analysis: NORINYL 1 80 21 DAY versus TRI LO MILI.
Peer-Reviewed Evidence
Head-to-head clinical analysis: NORINYL 1 80 21 DAY versus TRI LO MILI.
NORINYL 1+80 21-DAY vs TRI-LO-MILI
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: ethinyl estradiol suppresses gonadotropin release via negative feedback on the hypothalamic-pituitary axis; norgestimate binds to progesterone receptors, inhibiting ovulation and altering cervical mucus and 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 of placebo.
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.
Terminal elimination half-life: 20-24 hours; allows once-daily dosing for contraceptive efficacy.
Renal (40-60% as metabolites), fecal (20-30%)
Renal: approximately 50% as metabolites; biliary/fecal: approximately 40% as metabolites; 10% unchanged in urine.
Category C
Category C
Oral Contraceptive
Oral Contraceptive