Comparative Pharmacology
Head-to-head clinical analysis: LO LOESTRIN FE versus LO OVRAL.
Peer-Reviewed Evidence
Head-to-head clinical analysis: LO LOESTRIN FE versus LO OVRAL.
LO LOESTRIN FE vs LO/OVRAL
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Combination of ethinyl estradiol and norethindrone acetate suppresses gonadotropin-releasing hormone (GnRH) from the hypothalamus, reducing luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the pituitary, thereby inhibiting ovulation. The progestin component thickens cervical mucus, impeding sperm penetration, and alters endometrial receptivity. Ferrous fumarate provides supplemental iron.
Combination estrogen-progestin oral contraceptive; suppresses gonadotropin release, primarily FSH and LH, inhibiting ovulation; increases viscosity of cervical mucus, impeding sperm penetration; alters endometrial receptivity.
One tablet orally once daily. Each tablet contains norethindrone acetate 1 mg and ethinyl estradiol 10 mcg (24 active tablets) followed by ferrous fumarate 75 mg (2 inactive tablets).
One tablet (30 mcg ethinyl estradiol, 0.3 mg norgestrel) orally once daily for 28-day cycle (21 active, 7 placebo).
None Documented
None Documented
Norethindrone: ~8 hours (range 5–12 h); Ethinyl estradiol: ~14 hours (range 10–20 h). Terminal half-life supports once-daily dosing with steady-state reached within 7–14 days.
Norgestrel (levonorgestrel): 11-45 hours (mean ~24 hours); ethinyl estradiol: 7-21 hours (mean ~14 hours). Half-life increases slightly with repeated dosing due to saturable metabolism.
Renal (primarily as glucuronide conjugates of norethindrone and ethinyl estradiol): ~40% norethindrone metabolites, ~30% ethinyl estradiol metabolites; Fecal: ~30% norethindrone metabolites, ~40% ethinyl estradiol metabolites.
Urine (50-60% as conjugated metabolites), feces (30-40% as metabolites), enterohepatic recirculation present.
Category C
Category C
Combination Oral Contraceptive
Combination Oral Contraceptive