Comparative Pharmacology
Head-to-head clinical analysis: N E E 1 35 21 versus NORTREL 1 35 21.
Peer-Reviewed Evidence
Head-to-head clinical analysis: N E E 1 35 21 versus NORTREL 1 35 21.
N.E.E. 1/35 21 vs NORTREL 1/35-21
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Combination estrogen-progestin contraceptive: ethinyl estradiol (estrogen) and norethindrone (progestin). Suppresses gonadotropin (FSH, LH) release via negative feedback, inhibiting ovulation; increases cervical mucus viscosity to impede sperm penetration; alters endometrial development to reduce implantation likelihood.
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.
One tablet orally once daily for 21 days, followed by 7 days off.
One tablet orally once daily for 21 days, followed by 7 days off, then repeat.
None Documented
None Documented
Norethindrone: terminal half-life 7-8 hours; Ethinyl estradiol: terminal half-life 12-14 hours (with enterohepatic recycling). Clinically, steady state achieved after 5-7 days.
Norethindrone: 5-14 hours; Ethinyl estradiol: 17-24 hours. Steady-state achieved after 10 days.
Norethindrone (NET) and ethinyl estradiol (EE) are excreted primarily in urine (~50-60% as metabolites) and feces (~30-40% as metabolites); less than 1% excreted unchanged.
Renal 50-60% as metabolites, fecal 40-50% as conjugates, <1% unchanged
Category C
Category C
Oral Contraceptive
Oral Contraceptive