Comparative Pharmacology
Head-to-head clinical analysis: LOESTRIN 21 1 5 30 versus LOESTRIN FE 1 20.
Peer-Reviewed Evidence
Head-to-head clinical analysis: LOESTRIN 21 1 5 30 versus LOESTRIN FE 1 20.
LOESTRIN 21 1.5/30 vs LOESTRIN FE 1/20
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Combination estrogen-progestin contraceptive: suppresses gonadotropin release, inhibiting ovulation; increases viscosity of cervical mucus, impeding sperm penetration; alters endometrial morphology.
Combination oral contraceptive consisting of ethinyl estradiol and norethindrone acetate. Inhibits gonadotropin secretion (FSH, LH) via negative feedback on the hypothalamic-pituitary-ovarian axis, suppressing ovulation. Increases cervical mucus viscosity and alters endometrial structure, impeding sperm penetration and implantation.
One tablet (norethindrone acetate 1.5 mg/ethinyl estradiol 30 mcg) orally once daily for 21 consecutive days, followed by 7 days off therapy.
One tablet (norethindrone acetate 1 mg and ethinyl estradiol 20 mcg) orally once daily for 21 consecutive days, followed by one ferrous fumarate tablet (75 mg) orally once daily for 7 days.
None Documented
None Documented
Ethinyl estradiol: ~12-14 h; Norethindrone: ~5-12 h. Steady-state achieved in ~5-10 days.
Norethindrone: 6-9 hours (terminal). Ethinyl estradiol: 13-27 hours (terminal, mean 16 hours). Steady-state reached within 5-7 days.
Primarily hepatic metabolism; ~40-60% renal, 20-30% biliary/fecal.
Norethindrone: 50-60% renal (as metabolites), 20-30% fecal. Ethinyl estradiol: 40-50% renal (as glucuronide conjugates), 30-40% fecal (as sulfate conjugates).
Category C
Category C
Combined Oral Contraceptive
Combined Oral Contraceptive