Comparative Pharmacology
Head-to-head clinical analysis: NORTREL 0 5 35 21 versus TRI LEGEST 21.
Peer-Reviewed Evidence
Head-to-head clinical analysis: NORTREL 0 5 35 21 versus TRI LEGEST 21.
NORTREL 0.5/35-21 vs TRI-LEGEST 21
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
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.
Combination estrogen-progestin contraceptive; suppresses gonadotropins (FSH, LH), inhibits ovulation, alters cervical mucus and endometrium.
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.
One tablet orally once daily for 21 days, followed by 7 tablet-free days. Each tablet contains norgestimate 0.18 mg/ethinyl estradiol 0.025 mg (days 1-7), norgestimate 0.215 mg/ethinyl estradiol 0.025 mg (days 8-14), norgestimate 0.25 mg/ethinyl estradiol 0.025 mg (days 15-21).
None Documented
None Documented
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.
Ethinyl estradiol: 13-27 hours (mean ~17 hours); norgestimate active metabolite (norelgestromin): 22-36 hours (mean ~28 hours). Steady-state achieved within 5-10 days.
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.
Renal: approximately 50-60% as metabolites; fecal: approximately 40-50% (ethinyl estradiol and norgestimate metabolites excreted in bile and feces); less than 1% unchanged in urine.
Category C
Category C
Oral Contraceptive
Oral Contraceptive