Comparative Pharmacology
Head-to-head clinical analysis: LOESTRIN FE 1 5 30 versus NORINYL 1 35 21 DAY.
Peer-Reviewed Evidence
Head-to-head clinical analysis: LOESTRIN FE 1 5 30 versus NORINYL 1 35 21 DAY.
LOESTRIN FE 1.5/30 vs NORINYL 1+35 21-DAY
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Suppresses gonadotropin (FSH and LH) release via estrogen and progestin feedback inhibition, preventing ovulation; increases cervical mucus viscosity and alters endometrial lining.
Combination oral contraceptive containing norethindrone (progestin) and ethinyl estradiol (estrogen). Suppresses gonadotropin release (FSH, LH) via negative feedback on hypothalamic-pituitary-ovarian axis, inhibiting ovulation. Increases cervical mucus viscosity and alters endometrial structure to impair sperm penetration and implantation.
One tablet orally once daily at the same time each day for 21 consecutive days, followed by 7 days of placebo (ferrous fumarate) tablets, then restart.
One tablet orally once daily for 21 consecutive days, followed by 7 days off therapy.
None Documented
None Documented
Norethindrone: ~5-14 hours (terminal); Ethinyl estradiol: ~13-27 hours (terminal). Clinically, steady-state achieved within 5-7 days.
Norethindrone: 7-8 hours; Ethinyl estradiol: 13-27 hours (mean ~17 hours). Steady state achieved by day 10-14.
Renal: ~50-60% (norethindrone metabolites); Fecal: ~20-30% (norethindrone); Ethinyl estradiol: primarily renal (~40-50%) and fecal (~20-50%) as glucuronide and sulfate conjugates.
Renal (50-60% as metabolites, primarily glucuronide and sulfate conjugates) and fecal (30-40% as metabolites). Less than 1% excreted unchanged.
Category C
Category C
Combined Oral Contraceptive
Combined Oral Contraceptive