Comparative Pharmacology
Head-to-head clinical analysis: NORTREL 1 35 21 versus OVRAL.
Peer-Reviewed Evidence
Head-to-head clinical analysis: NORTREL 1 35 21 versus OVRAL.
NORTREL 1/35-21 vs OVRAL
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Combination of ethinyl estradiol (estrogen) and norethindrone (progestin) suppresses gonadotropin (FSH and LH) release from the pituitary, inhibiting ovulation, altering cervical mucus to impede sperm penetration, and inducing endometrial changes that reduce implantation likelihood.
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 orally once daily for 21 days, followed by 7 days off, then repeat.
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; Ethinyl estradiol: 17-24 hours. Steady-state achieved after 10 days.
Norgestrel: 24–32 hours; Ethinyl estradiol: 12–18 hours; steady-state achieved after 5–7 days
Renal 50-60% as metabolites, fecal 40-50% as conjugates, <1% unchanged
Renal (60% as metabolites, ~40% unchanged); biliary/fecal (40%)
Category C
Category C
Oral Contraceptive
Oral Contraceptive