Comparative Pharmacology
Head-to-head clinical analysis: NORTREL 0 5 35 28 versus OVRAL.
Peer-Reviewed Evidence
Head-to-head clinical analysis: NORTREL 0 5 35 28 versus OVRAL.
NORTREL 0.5/35-28 vs OVRAL
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Norethindrone and ethinyl estradiol are a combination hormonal contraceptive. Norethindrone suppresses gonadotropin release (FSH and LH) from the pituitary, inhibiting ovulation. Ethinyl estradiol stabilizes the endometrium and enhances the contraceptive effect by inhibiting gonadotropin secretion.
OVRAL is a combination oral contraceptive containing ethinyl estradiol and norgestrel. It inhibits ovulation by suppressing gonadotropin-releasing hormone (GnRH) secretion from the hypothalamus, reducing follicle-stimulating hormone (FSH) and luteinizing hormone (LH) release from the pituitary. Additionally, it increases cervical mucus viscosity and alters endometrial receptivity, impeding sperm penetration and implantation.
1 tablet orally once daily for 28 days (21 active tablets containing 0.5 mg norethindrone and 35 mcg ethinyl estradiol, followed by 7 placebo tablets).
One tablet (norgestrel 0.3 mg with ethinyl estradiol 0.03 mg) orally once daily for 21 days followed by 7 days of placebo.
None Documented
None Documented
Norethindrone: 7.2-9.2 hours; Ethinyl estradiol: 13-27 hours. Clinical context: Steady state reached in 5-7 days; half-life supports once-daily dosing.
Norgestrel: 24–32 hours; Ethinyl estradiol: 12–18 hours; steady-state achieved after 5–7 days
Renal: ~40% as metabolites; Biliary/Fecal: ~60% as metabolites; <5% unchanged.
Renal (60% as metabolites, ~40% unchanged); biliary/fecal (40%)
Category C
Category C
Oral Contraceptive
Oral Contraceptive