Comparative Pharmacology
Head-to-head clinical analysis: NORTREL 1 35 28 versus OVRAL.
Peer-Reviewed Evidence
Head-to-head clinical analysis: NORTREL 1 35 28 versus OVRAL.
NORTREL 1/35-28 vs OVRAL
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Combination of ethinyl estradiol and norethindrone inhibits gonadotropin secretion via negative feedback on the hypothalamic-pituitary-ovarian axis, suppressing ovulation. Additionally, increases cervical mucus viscosity and alters endometrial receptivity.
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.
One tablet (norethindrone 1 mg + ethinyl estradiol 35 mcg) orally once daily for 28 days, followed by a 7-day placebo period (if using 28-day pack) or continuous if using 21-day pack with 7-day off. Start on first day of menstrual period.
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: 5-14 hours (terminal); ethinyl estradiol: 13-27 hours (terminal). Context: steady-state after 5-7 days; dose adjustment in hepatic impairment.
Norgestrel: 24–32 hours; Ethinyl estradiol: 12–18 hours; steady-state achieved after 5–7 days
Renal 60-70% (as glucuronide and sulfate conjugates), fecal 20-30% (via biliary excretion).
Renal (60% as metabolites, ~40% unchanged); biliary/fecal (40%)
Category C
Category C
Oral Contraceptive
Oral Contraceptive