Comparative Pharmacology
Head-to-head clinical analysis: NORTREL 7 7 7 versus TRI LEGEST FE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: NORTREL 7 7 7 versus TRI LEGEST FE.
NORTREL 7/7/7 vs TRI-LEGEST FE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Combination estrogen-progestin oral contraceptive. Suppresses gonadotropin release, inhibiting ovulation. Increases cervical mucus viscosity and alters endometrial receptivity.
Tri-Legest FE is a combination oral contraceptive containing ethinyl estradiol and norethindrone acetate. It prevents ovulation by inhibiting gonadotropin release (FSH and LH) and alters cervical mucus and endometrial lining to impede sperm penetration and implantation.
One tablet orally once daily, taken at the same time each day. Each tablet contains norethindrone 0.5 mg/ethinyl estradiol 35 mcg for days 1-7, norethindrone 0.75 mg/ethinyl estradiol 35 mcg for days 8-14, and norethindrone 1 mg/ethinyl estradiol 35 mcg for days 15-21, followed by 7 placebo tablets.
One tablet orally once daily for 28-day cycle: 21 days active tablets (norethindrone/ethinyl estradiol) followed by 7 days placebo. For contraception only.
None Documented
None Documented
Norelgestromin terminal half-life is approximately 28 hours; ethinyl estradiol terminal half-life is approximately 17 hours. The extended half-life supports once-weekly dosing.
Norethindrone: 7-8 hours; Ethinyl estradiol: 18 hours (terminal). Steady-state reached after 7 days; clinical contraceptive efficacy requires consistent dosing.
Renal excretion of metabolites (primarily ethinyl estradiol and norelgestromin conjugates) accounts for approximately 50% of elimination; fecal/biliary excretion accounts for the remainder (about 35-40% fecal, 10-15% biliary).
Renal: ~60% (metabolites), Fecal: ~30% (metabolites), Biliary: minor (~5% as conjugates)
Category C
Category C
Oral Contraceptive
Oral Contraceptive