Comparative Pharmacology
Head-to-head clinical analysis: NORLESTRIN 21 1 50 versus ORTHO NOVUM 7 14 28.
Peer-Reviewed Evidence
Head-to-head clinical analysis: NORLESTRIN 21 1 50 versus ORTHO NOVUM 7 14 28.
NORLESTRIN 21 1/50 vs ORTHO-NOVUM 7/14-28
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Combination oral contraceptive containing norethindrone (progestin) and ethinyl estradiol (estrogen). Inhibits ovulation via suppression of gonadotropins (LH, FSH). Enhances cervical mucus viscosity, reducing sperm penetration. Thins endometrium, decreasing implantation likelihood.
Combination oral contraceptive containing ethinyl estradiol and norethindrone. Suppresses gonadotropin release (FSH, LH) via negative feedback, inhibiting ovulation. Also increases cervical mucus viscosity and alters endometrial receptivity.
One tablet (1 mg norethindrone acetate/50 mcg ethinyl estradiol) orally once daily for 21 days, followed by 7 days off therapy.
One tablet daily for 28 days; each tablet contains norethindrone 0.5 mg and ethinyl estradiol 0.035 mg (days 1-7), norethindrone 0.75 mg and ethinyl estradiol 0.035 mg (days 8-14), norethindrone 1 mg and ethinyl estradiol 0.035 mg (days 15-21), and placebo (days 22-28). Take at same time each day.
None Documented
None Documented
Norethindrone terminal half-life: 5-14 hours; ethinyl estradiol terminal half-life: 10-20 hours. Clinical context: steady-state reached within 5-7 days, clinically significant for missed dose management.
Ethinyl estradiol: ~13-27 h (mean 17 h); Norethindrone: ~5-14 h (mean 8 h). Clinical context: steady-state achieved after ~5 days; half-life supports daily dosing.
Norethindrone: renal (33% as metabolites), fecal (50%); ethinyl estradiol: renal (40% as glucuronide conjugates), fecal (60%)
Renal: ~50-60% (metabolites); biliary/fecal: ~30-40% (metabolites); unchanged drug <1% in urine.
Category C
Category C
Oral Contraceptive
Oral Contraceptive