Comparative Pharmacology
Head-to-head clinical analysis: N E E 1 35 28 versus NORTREL 0 5 35 21.
Peer-Reviewed Evidence
Head-to-head clinical analysis: N E E 1 35 28 versus NORTREL 0 5 35 21.
N.E.E. 1/35 28 vs NORTREL 0.5/35-21
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Combination oral contraceptive; ethinyl estradiol and norethindrone suppress gonadotropin (FSH and LH) release, preventing ovulation. Also cause cervical mucus thickening and endometrial changes.
Combination hormonal contraceptive containing norethindrone (a progestin) and ethinyl estradiol (an estrogen). Norethindrone inhibits ovulation by suppressing gonadotropin release (LH and FSH) and alters cervical mucus and endometrial receptivity. Ethinyl estradiol provides negative feedback on the hypothalamic-pituitary-ovarian axis, further suppressing ovulation.
One tablet orally once daily for 28 days; each tablet contains norethindrone 1 mg and ethinyl estradiol 35 mcg.
1 tablet orally once daily for 21 days, followed by 7 days off. Each tablet contains 0.5 mg norethindrone and 35 mcg ethinyl estradiol.
None Documented
None Documented
Ethinyl estradiol: ~15-19 hours (linear pharmacokinetics); Norethindrone: ~7-9 hours (terminal half-life; steady-state achieved within 5-7 days)
Norethindrone: terminal half-life approximately 7-8 hours. Ethinyl estradiol: terminal half-life approximately 13-27 hours, mean about 17 hours. Ethinyl estradiol exhibits a longer half-life due to enterohepatic recirculation and extensive tissue distribution.
Renal: ~50-60% (metabolites, primarily glucuronide conjugates); Fecal: ~30-40% (biliary excretion of metabolites); Unchanged drug: <5%
Norethindrone is primarily excreted renally (approximately 60-80% as metabolites) and approximately 20-40% fecally. Ethinyl estradiol is excreted renally (about 40%) and fecally (about 60%) as glucuronide and sulfate conjugates.
Category C
Category C
Oral Contraceptive
Oral Contraceptive